The Johns Hopkins University Applied Physics Laboratory (APL) is to send a space probe closer to the sun than any probe has ever gone - and what he finds could revolutionize what we know about our Star and the solar wind influenced by the fact that everything our solar system.
NASA has developed APL develop the ambitious mission Solar Probe, will study the streams of charged particles of the sun hurls into space from a vantage point within the Sun's corona - its outer atmosphere - where the processes that produce heat, corona and solar wind. The next solar sample approach would zip past the sun at 125 miles per second, protected by a carbon composite heat shield, the weight of up to 2600 ° F and survive blasts of radiation energy and dust not on a level with which any previous spacecraft .
Experts in the U.S. and abroad have grappled with this mission concept for more than 30 years run in seemingly insurmountable technological and budgetary policy restrictions. But in February an APL-led team a sample of solar engineering and design study mission to the NASA request to detail how the robot mission could be. The study uses a team APL study in 2005 as a baseline, but then clearly changed the concept to meet demanding cost and technical conditions set by NASA.
"We knew we were on the right track," said Andrew Dantzler, Solar Probe project manager at Apl. "Now we have it all together in an innovative package, the technology is within reach, the concept is feasible and the entire mission can be done for less than $ 750 million [in fiscal year 2007 U.S. dollars] or on the Cost of a medium - Class planetary mission. NASA decided it was time. "
APL designed and built the spacecraft on a timetable for the introduction in 2015. The compact, solar-powered probe would weigh about 1000 pounds; preliminary designs include a 9-foot-diameter, 6-inch-thick carbon-filled foam solar shield summit of the spacecraft body. Two sets of solar arrays would retract or extend, as the spacecraft swings in direction or away from the sun while several loops around the inner solar system, so sure that the plates remain in the correct temperatures and performance levels. At its closest pass the spacecraft must survive solar intensity more than 500 times what spacecraft experiences during an orbit of the earth.
Solar Probe turning seven Venus flybys in the course of almost 7 years gradually shrink its orbit around the sun, come as close as 4.1 million miles (6.6 million kilometers) to the sun, even within the orbit of Mercury and about eight times closer than any spacecraft has before.
Solar Probe is a combination of in-place and remote measurements to achieve the mission is primarily scientific objectives: determining the structure and dynamics of the magnetic fields on the sources of solar wind; track the flow of energy, heats the corona and accelerates the solar wind system to determine what mechanisms to accelerate and transport energetic particles and explore dusty plasma in the vicinity of the sun and its influence on the solar wind and energetic particle formation. Details are set out in a solar probe for science and technology definition study team that NASA version will later this year. NASA version is also a separate announcement of opportunity for the spacecraft's science payload.
"Solar Probe is a true mission of exploration," says Dr. Robert Decker, Solar Probe project scientist at Apl. "For example, the spacecraft will go close enough to the sun to observe the solar wind speed from subsonic to supersonic, and it will fly even though the cradle of the highest solar-energy particles. And, as with all of the missions of discovery, solar Sample is likely that more questions than it answers. "
APL's experience in developing spacecraft to explore the Sun-Earth relationship - or work near the sun - ACE, which recently marked its 10th Year of sampling energetic particles between Earth and sun; time setting, is currently examining solar effects on the Earth's upper atmosphere, the two STEREO probes, which have snapped the first 3-D images of explosive solar events called coronal mass ejections, and the radiation Belt Storm probes, consider the regions of energetic particles trapped by Earth's magnetic field.
Solar sample is fortified with heat-resistant technologies developed for APL MESSENGER spacecraft, which completed its first flyby of Mercury in January and will begin orbiting the planet and that in 2011. Solar Probe solar shield concept was partly influenced by the designs of the Messenger Sonnensegel
Rabu, 25 Juni 2008
Small Planet, Small Star
Astronomers discovered an extrasolar planet only three times more massive than our own, nor the smallest observed orbiting a normal star. The star itself is not large, perhaps as little as one twentieth of the mass of our sun, suggesting that the research team that often relatively low-mass stars can be good candidates for hosting Earth-like planets.
Does Ange by David Bennett of the University of Notre Dame, the international research team presented its findings at a press conference Monday, 2 June 2008, at 11:30 CDT clock at the American Astronomical Society Meeting in St. Louis, Missouri.
"Our discovery shows that even the lowest mass stars may host planets," says Bennett. "No planet yet found orbiting stars with masses less than 20 percent higher than that of the sun, but this finding suggests that even the smallest stars can host planet."
The astronomers used a technique called micro-lensing effect to find the planets, a method that can potentially planet, one tenth the mass of our own.
The gravitational constant Microlensing system, which came from Einstein's general theory of relativity, based on observations of stars, brighten when an object such as another star passing directly in front of them (relative to an observer, in this case the earth). The gravity of the passing star acts as a lens, much like a huge magnifying glass. If a planet orbiting the star gone, his presence is evident in the way of the background star brightens. A complete explanation of the art follows this release.
"This discovery shows the sensitivity of the Microlensing method to find low-mass planets, and we hope to discover the first Earth-mass planet in the near future," said Bennett.
Use of standard nomenclature, the Star-hosting of the newly discovered planet is synchronized MOA-2007-BLG-192L with MOA indication of the observatory, 2007 has been designated the Year of Microlensing event occurred, BLG stands for "Bulge, 192, indicating the Microlensing observation of the 192nd MOA this year and the L-lens with an indication of the stars in contrast to the background of other star in the distance. The planet has the name, but adds a provision letter it as an additional item in the star's solar system, says MOA-2007-BLG-192Lb.
MOA-2007-BLG-192L lives 3000 light years away and is available as a low-mass star burning hydrogen, an enabling nuclear reactions in its core business as our sun does, or a brown dwarf, an object like a star even without the mass to get Nuclear reactions in its core. The researchers were unable to confirm the category of the star fits in the nature of the observations and the margin of error.
With support from the National Science Foundation (NSF), Bennett was one of the pioneers in the use of micro-lens effect to demonstrate low mass planets. He has worked with employees around the world to find a number of planets, the increasingly closer in size to our own.
For the latest discovery, the research staff took advantage of two international cooperation Telescope: Microlensing Observations in Astrophysics (MOA), which includes Bennett, and the Optical Gravitational Lensing Experiment (OGLE).
Researchers in New Zealand from the first measurements of the new planet and its star with the new MOA-II telescope on Mt. John Observatory. The observatory is MOA-CAM3 camera, in an observation, can capture an image of the sky 13 times larger than the area of the full moon. Researchers in Chile made follow-up observations with high angular resolution adaptive optics images at the Very Large Telescope of the European Southern Observatory. The data from the observations was analysed by scientists around the world hailing from five continents.
"This discovery is very exciting because it means, Earth-mass planets can form around low-mass stars, are very common," said Michael Briley, astronomer and NSF officer who supervises the Bennett's. "It is a further important step in the search for Earth-like planets in the habitable zones of other stars, and it would not have been possible without the international cooperation between professional and amateur astronomers dedicated to measure these signals.
Does Ange by David Bennett of the University of Notre Dame, the international research team presented its findings at a press conference Monday, 2 June 2008, at 11:30 CDT clock at the American Astronomical Society Meeting in St. Louis, Missouri.
"Our discovery shows that even the lowest mass stars may host planets," says Bennett. "No planet yet found orbiting stars with masses less than 20 percent higher than that of the sun, but this finding suggests that even the smallest stars can host planet."
The astronomers used a technique called micro-lensing effect to find the planets, a method that can potentially planet, one tenth the mass of our own.
The gravitational constant Microlensing system, which came from Einstein's general theory of relativity, based on observations of stars, brighten when an object such as another star passing directly in front of them (relative to an observer, in this case the earth). The gravity of the passing star acts as a lens, much like a huge magnifying glass. If a planet orbiting the star gone, his presence is evident in the way of the background star brightens. A complete explanation of the art follows this release.
"This discovery shows the sensitivity of the Microlensing method to find low-mass planets, and we hope to discover the first Earth-mass planet in the near future," said Bennett.
Use of standard nomenclature, the Star-hosting of the newly discovered planet is synchronized MOA-2007-BLG-192L with MOA indication of the observatory, 2007 has been designated the Year of Microlensing event occurred, BLG stands for "Bulge, 192, indicating the Microlensing observation of the 192nd MOA this year and the L-lens with an indication of the stars in contrast to the background of other star in the distance. The planet has the name, but adds a provision letter it as an additional item in the star's solar system, says MOA-2007-BLG-192Lb.
MOA-2007-BLG-192L lives 3000 light years away and is available as a low-mass star burning hydrogen, an enabling nuclear reactions in its core business as our sun does, or a brown dwarf, an object like a star even without the mass to get Nuclear reactions in its core. The researchers were unable to confirm the category of the star fits in the nature of the observations and the margin of error.
With support from the National Science Foundation (NSF), Bennett was one of the pioneers in the use of micro-lens effect to demonstrate low mass planets. He has worked with employees around the world to find a number of planets, the increasingly closer in size to our own.
For the latest discovery, the research staff took advantage of two international cooperation Telescope: Microlensing Observations in Astrophysics (MOA), which includes Bennett, and the Optical Gravitational Lensing Experiment (OGLE).
Researchers in New Zealand from the first measurements of the new planet and its star with the new MOA-II telescope on Mt. John Observatory. The observatory is MOA-CAM3 camera, in an observation, can capture an image of the sky 13 times larger than the area of the full moon. Researchers in Chile made follow-up observations with high angular resolution adaptive optics images at the Very Large Telescope of the European Southern Observatory. The data from the observations was analysed by scientists around the world hailing from five continents.
"This discovery is very exciting because it means, Earth-mass planets can form around low-mass stars, are very common," said Michael Briley, astronomer and NSF officer who supervises the Bennett's. "It is a further important step in the search for Earth-like planets in the habitable zones of other stars, and it would not have been possible without the international cooperation between professional and amateur astronomers dedicated to measure these signals.
Black Hole Light Show
It is known that black holes can be slow time for a crawl and tidally stretch large objects in spaghetti-like strands. However, according to new theoretical research of two NASA astrophysicist, the wrenching gravity just outside the outer limit of a black hole is yet another bizarre effect: light echoes.
"The light echoes come because of the severe warping of space-time predicted by Einstein," says KEIGO Fukumura of NASA's Goddard Space Flight Center. "If the black hole spins quickly, it can literally drag the surrounding space, and this may take some wild special effects."
Many black holes are surrounded by disks searing hot gas, swirl around to almost the speed of light. Hot spots within these sheets sometimes encounter random bursts of X-rays, which have been identified by an orbiting X-ray observatories. But after Fukumura and his colleague, Demosthenes Kazanas, things get interesting if they take account of Einstein's general theory of relativity, which describes how extremely massive objects like black holes actually chain and drag the surrounding space-time.
Many of these X-ray photons travel to Earth by different paths around the black hole. Because the black hole of the extreme gravity warps the surrounding space-time, it prevents the flight paths of the photons so that they come here with a lag, depending on the relative positions of the X-ray flare, the black hole, and the earth.
But if the black hole rotates very fast, then Fukumura and Kazanas calculations, the delay between the photons is constant, regardless of the source position. They discovered that the rapidly spinning black holes, about 75 percent of the X-ray photons arrive in the Observer after completing a fraction of an orbit around the black hole, while the remaining photons travel the exact same fraction of plus one or more full - Railways.
"For every X-ray burst from a hot spot, the observers will be two or more flashes, separated by a constant distance, so that a signal from a totally random collection of bursts of hot spots in various positions itself contains an echo" Kazanas says.
Although difficult to see the raw data, astronomers can a Fourier analysis or other statistical methods to collect these hidden echoes. Among other things, a Fourier analysis is a mathematical tool for extracting periodic behavior on a signal that would otherwise seem totally random. The echoes seems as quasi-periodic oscillations (QPOs). An example of a QPO with a period of 10 seconds could exhibit peaks at 9, 21, 30, 39, 51 and 61 seconds.
If you consider a 10-solar-mass black hole, that a dying star, and if the black hole spins more than 95 percent of the maximum possible speed, the period of his QPOs would be about 0.7 milliseconds, which corresponds to about 1400 peaks per second, three times higher than any QPOs that have been observed around black holes. NASA's Rossi X-ray Timing Explorer satellite could such a measure high-frequency QPOs, but the signal would have to be very strong.
Detecting these high-frequency QPOs would do more than just another confirmation of the prediction of Einstein's theory. It would be a real treasure trove of information about the Black Hole. The frequency of QPOs depends on the black hole mass, so that the recognition of this echo effect would give astronomers an accurate way to measure the mass of black holes. In addition, notes Kazanas, "This echoes only occur if a black hole is spinning near their maximum speed possible so that it now say that the astronomers the black hole spins really fast."
"The light echoes come because of the severe warping of space-time predicted by Einstein," says KEIGO Fukumura of NASA's Goddard Space Flight Center. "If the black hole spins quickly, it can literally drag the surrounding space, and this may take some wild special effects."
Many black holes are surrounded by disks searing hot gas, swirl around to almost the speed of light. Hot spots within these sheets sometimes encounter random bursts of X-rays, which have been identified by an orbiting X-ray observatories. But after Fukumura and his colleague, Demosthenes Kazanas, things get interesting if they take account of Einstein's general theory of relativity, which describes how extremely massive objects like black holes actually chain and drag the surrounding space-time.
Many of these X-ray photons travel to Earth by different paths around the black hole. Because the black hole of the extreme gravity warps the surrounding space-time, it prevents the flight paths of the photons so that they come here with a lag, depending on the relative positions of the X-ray flare, the black hole, and the earth.
But if the black hole rotates very fast, then Fukumura and Kazanas calculations, the delay between the photons is constant, regardless of the source position. They discovered that the rapidly spinning black holes, about 75 percent of the X-ray photons arrive in the Observer after completing a fraction of an orbit around the black hole, while the remaining photons travel the exact same fraction of plus one or more full - Railways.
"For every X-ray burst from a hot spot, the observers will be two or more flashes, separated by a constant distance, so that a signal from a totally random collection of bursts of hot spots in various positions itself contains an echo" Kazanas says.
Although difficult to see the raw data, astronomers can a Fourier analysis or other statistical methods to collect these hidden echoes. Among other things, a Fourier analysis is a mathematical tool for extracting periodic behavior on a signal that would otherwise seem totally random. The echoes seems as quasi-periodic oscillations (QPOs). An example of a QPO with a period of 10 seconds could exhibit peaks at 9, 21, 30, 39, 51 and 61 seconds.
If you consider a 10-solar-mass black hole, that a dying star, and if the black hole spins more than 95 percent of the maximum possible speed, the period of his QPOs would be about 0.7 milliseconds, which corresponds to about 1400 peaks per second, three times higher than any QPOs that have been observed around black holes. NASA's Rossi X-ray Timing Explorer satellite could such a measure high-frequency QPOs, but the signal would have to be very strong.
Detecting these high-frequency QPOs would do more than just another confirmation of the prediction of Einstein's theory. It would be a real treasure trove of information about the Black Hole. The frequency of QPOs depends on the black hole mass, so that the recognition of this echo effect would give astronomers an accurate way to measure the mass of black holes. In addition, notes Kazanas, "This echoes only occur if a black hole is spinning near their maximum speed possible so that it now say that the astronomers the black hole spins really fast."
Old Galaxies Discovered
Astronomers at Rutgers and Penn State universities have discovered galaxies in the distant universe, the ancestors of spiral galaxies like our Milky Way. This ancient objects, some of the first galaxies depending on the shape, is to see how they looked when the universe was only 2 billion years old. Today, researchers peg the age of the universe at 13.7 billion years, so that the light from these galaxies travelled almost 12 billion years on Earth. The newly discovered galaxies are quite small, one-tenth of the size and one-twentieth of the mass of our Milky Way. They also have fewer stars, only a fortieth as many as in the Milky Way. From ground-based telescopes, they look like single stars in size. Latest images from the Hubble Space Telescope, but they show as regions of active star formation. "Finding these objects and discover that they are a step in the development of our galaxy is akin to the search for a fossil key on the path of human evolution," says Eric Gawiser, Assistant Professor in the Department of Physics and Astronomy at Rutgers School of Arts and Sciences. The researchers found that these galaxies have been fertile ground for new stars, which burned hot and bright. These stars ionized the hydrogen atoms around them, stripping them of their electrons and that they emit a fairy tale to tell of hot-band ultraviolet light known as Lyman-alpha. The researchers also noted that several of these galaxies, sometimes 10 or more, pulled together over the ensuing few billion years into a single spiral galaxy. "The Hubble Space Telescope has striking images of these early galaxies, where 10 times the resolution of ground-based telescopes," says Caryl Gronwall, Senior Research Associate at the Penn State's Department of Astronomy & Astrophysics. "They come in a variety of shapes, round, oblong, and even somewhat linear, and we will begin to precise measurements of their size." The astronomers discovered these galaxies as part of a 5-year census of galaxies in the early universe, a project called MUSYC (multi-wavelength survey by Yale and Chile). Gawiser, while a National Science Foundation (NSF) Astronomy and Astrophysics Postdoctoral Fellow at Yale, launched a search for different types of galaxies could be a precursor of the Milky Way-spirals; Gronwall led an investigation into the luminosity, density and distribution of the distinctive Lyman Alpha-emitters. Their statistical analysis and computer simulations of galaxies, such as clusters led to the conclusion reported for the first time in December 2007: Lyman-alpha emitters are the ancestors of spiral galaxies. "We knew from our understanding of the cosmological theory that spiral galaxies had a low mass galaxies like this," said Gawiser. "The challenge is that they actually find. We'd seen other galaxies early universe, but they were bigger and, in elliptical galaxies, not spirals." The astronomers undertook four types of observations to find and characterize the objects they were looking for. It takes the first step, in fact, the Lyman-alpha-emitting galaxies midst of all visible objects of Deep Space, with the 4-meter Blanco telescope at the NSF Cerro Tololo Inter-American Observatory in Chile. To measure their distance, they used the Magellan Telescope at Las Camp Anas Observatory in Chile, for measuring the redshift, an effect that shows how fast an object from the look back on a rapidly expanding universe. (The redshift in which they studied these galaxies is 3.1.) To determine how many stars are in the galaxies, they used the NASA Spitzer Space Telescope infrared array camera. And to determine how large the galaxies, they used the NASA Hubble Space Telescope's Advanced Camera for Surveys. "Astronomy has long been a model, where large surveys, followed by detailed studies of the interesting objects they find," says Nigel Sharp, program officer in NSF's division of astronomical sciences. "This beautiful couples the large area, wide-angle field of view of our ground-based telescope with the sharp focus of the Hubble that the probe in pale light. This team has the closest yet to find young galaxies that are similar to our own Milky Way in the Infancy. " | ||
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A Trio Of Super-Earths
Today, in an international conference, a team of European astronomers announced a remarkable breakthrough in the field of extrasolar planets. With the HARPS instrument on the ESO La Silla observatory, they've found a system of triple super-earth around the star HD 40307th In addition, searches of their total sample and harps, the astronomers are a total of 45 candidates planet with a mass below 30 Earth masses and an orbital period of less than 50 days. This means that a solar-star of three ports such planets.
"Does every single star port planet, and if so, how many?"
Miracle planet hunter Michel Mayor of Geneva Observatory. "We can not yet know the answer, but we make great progress towards."
Since the discovery in 1995 of a planet around the star 51 Pegasi by Mayor and Didier Queloz, more than 270 exoplanets have been found, mostly around solar-like stars. Most of these planets are giants, like Jupiter or Saturn, and current statistics show that about 1 of
Stars 14 ports this kind of planet.
"With the advent of much more precise instruments such as the HARPS spectrograph on the ESO 3.6-m telescope at La Silla, we can now discover smaller planets with masses 2 to 10 times the mass of the earth,"
Says Stephane Udry, the mayor colleagues. Such planets are called super-earth, because they are more massive than the Earth, but less massive than Uranus and Neptune (about 15 Earth masses).
The group of astronomers have now discovered a system of three "super-earth to a more normal star, which is slightly less massive than our sun and located 42 light years away in the direction of the southern constellation Doradus and Pictor.
"We have very precise measurements of the speed of the star HD
40307 in the last five years, which clearly show the presence of three planets, "says Mayor.
The planet, with 4.2, 6.7 and 9.4 times the mass of Earth orbit the star with periods of 4.3, 9.6 and 20.4 days, respectively.
"The interference by the planets are really small - the mass of the smallest planet is a hundred thousand times smaller than the star - and only the high sensitivity of the HARPS made it possible to detect," says co-author Francois Bouchy, from the Institute Astrophysique de Paris, France.
Because each planet induces a movement of the star of only a few meters per second.
At the same conference, the team of astronomers announced the discovery of two other planetary systems, even with the HARPS spectrograph. In one, a super-Earth (7.5 masses) orbiting the star HD 181433 to 9.5 days. This star has a Jupiter-like planet with a period of close to 3 years. The second system includes a 22-mass of the planet earth with a duration of 4 days and a Saturn-like planets with a 3-year period as well.
"Of course these planets are only the tip of the iceberg," says Mayor.
"The analysis of all the stars studied with HARPS shows that around one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital data shorter periods than 50 days."
A planet in a narrow, short-period orbit is in fact easier to find than a in a broad, long-period orbit.
"It is very likely that there are many other planet: not only super-Earth and Neptune-like planets with longer periods, but also Earth-like planets, we can not recognize it yet. Add it to the Jupiter-like Planets already known, and you may well arrive at the conclusion that planets are everywhere, "concludes Udry.
"Does every single star port planet, and if so, how many?"
Miracle planet hunter Michel Mayor of Geneva Observatory. "We can not yet know the answer, but we make great progress towards."
Since the discovery in 1995 of a planet around the star 51 Pegasi by Mayor and Didier Queloz, more than 270 exoplanets have been found, mostly around solar-like stars. Most of these planets are giants, like Jupiter or Saturn, and current statistics show that about 1 of
Stars 14 ports this kind of planet.
"With the advent of much more precise instruments such as the HARPS spectrograph on the ESO 3.6-m telescope at La Silla, we can now discover smaller planets with masses 2 to 10 times the mass of the earth,"
Says Stephane Udry, the mayor colleagues. Such planets are called super-earth, because they are more massive than the Earth, but less massive than Uranus and Neptune (about 15 Earth masses).
The group of astronomers have now discovered a system of three "super-earth to a more normal star, which is slightly less massive than our sun and located 42 light years away in the direction of the southern constellation Doradus and Pictor.
"We have very precise measurements of the speed of the star HD
40307 in the last five years, which clearly show the presence of three planets, "says Mayor.
The planet, with 4.2, 6.7 and 9.4 times the mass of Earth orbit the star with periods of 4.3, 9.6 and 20.4 days, respectively.
"The interference by the planets are really small - the mass of the smallest planet is a hundred thousand times smaller than the star - and only the high sensitivity of the HARPS made it possible to detect," says co-author Francois Bouchy, from the Institute Astrophysique de Paris, France.
Because each planet induces a movement of the star of only a few meters per second.
At the same conference, the team of astronomers announced the discovery of two other planetary systems, even with the HARPS spectrograph. In one, a super-Earth (7.5 masses) orbiting the star HD 181433 to 9.5 days. This star has a Jupiter-like planet with a period of close to 3 years. The second system includes a 22-mass of the planet earth with a duration of 4 days and a Saturn-like planets with a 3-year period as well.
"Of course these planets are only the tip of the iceberg," says Mayor.
"The analysis of all the stars studied with HARPS shows that around one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital data shorter periods than 50 days."
A planet in a narrow, short-period orbit is in fact easier to find than a in a broad, long-period orbit.
"It is very likely that there are many other planet: not only super-Earth and Neptune-like planets with longer periods, but also Earth-like planets, we can not recognize it yet. Add it to the Jupiter-like Planets already known, and you may well arrive at the conclusion that planets are everywhere, "concludes Udry.
Phoenix Makes First Trench In Science Reserve
NASA's Phoenix Mars Lander began digging in an area called Wonderland early Tuesday, taking his first ground ball from a polygonal surface feature within the national park region, the mission scientists were for the preservation of science.
The lander's robot arm created the new test trench called Snow White, 17 On June 22nd Martian day, or Sol, after the Phoenix spacecraft landed on 25 May. New planned academic activities will resume no earlier than 24 Sol as engineers examine how the spacecraft handling is greater than expected amounts of data.
During the dig Tuesday, the arm may not reach the hard white material, possibly ice, that Phoenix suspended earlier in the first trench dug into the Martian soil.
That is exactly what the scientists expected, and both wanted. The Snow White trench is located near the middle of a relatively flat hummock or polygon, the name Cheshire Cat, where scientists predict it will take more or thick layers of soil above ground possible white material.
The Snow White trench is about two centimeters deep and 30 centimetres long. The Phoenix-team plans at least another day of digging deeper into the ditch Snow White.
It will examine the soil structure in the Snow White trench to decide at what depth they collect samples from a trench future, around the middle of the polygon.
Meanwhile, the Thermal and Evolved Gas Analyzer (TEGA) instrument will continue its ongoing experiment in the first of its eight furnaces.
TEGA has eight separate small ovens to bake and sniff the earth to seek volatile components, such as water. The baking takes place in three different temperature areas.
The lander's robot arm created the new test trench called Snow White, 17 On June 22nd Martian day, or Sol, after the Phoenix spacecraft landed on 25 May. New planned academic activities will resume no earlier than 24 Sol as engineers examine how the spacecraft handling is greater than expected amounts of data.
During the dig Tuesday, the arm may not reach the hard white material, possibly ice, that Phoenix suspended earlier in the first trench dug into the Martian soil.
That is exactly what the scientists expected, and both wanted. The Snow White trench is located near the middle of a relatively flat hummock or polygon, the name Cheshire Cat, where scientists predict it will take more or thick layers of soil above ground possible white material.
The Snow White trench is about two centimeters deep and 30 centimetres long. The Phoenix-team plans at least another day of digging deeper into the ditch Snow White.
It will examine the soil structure in the Snow White trench to decide at what depth they collect samples from a trench future, around the middle of the polygon.
Meanwhile, the Thermal and Evolved Gas Analyzer (TEGA) instrument will continue its ongoing experiment in the first of its eight furnaces.
TEGA has eight separate small ovens to bake and sniff the earth to seek volatile components, such as water. The baking takes place in three different temperature areas.
Newly Born Twin Stars Show Surprising Differences
A new study, published in the 19th June issue of the journal Nature, suggests that a star in a series of identical twin stars, formed much earlier than the others. Because astrophysicists have assumed that the binary stars form the discovery represents an important new test for a successful star formation theories, forcing theorists back to the drawing board to determine whether their models can produce binary files with stars, taken at different times .
The twins were in the Orion Nebula, a well-known stellar nursery, which is 1500 light years away. The newly formed stars are about 1 million years old. With a full life of about 50 billion years, making it equivalent to 1-day-old human baby.
"Very young superpower binary files from it are the Rosetta stone to us about the history of life newly formed stars," says Keivan Stassun, Associate Professor of Astronomy at the University of Vanderbilt. He and Robert D. Mathieu from the University of Wisconsin-Madison initiated the project.
Superpower binaries are pairs of stars that revolve around an axis perpendicular to the direction to Earth. This orientation allows astronomers to determine the rate that the two stars orbit around each other-even if they can not resolve individual stars by measuring the periodic fluctuations in brightness, if the star pass against each other. With this information, the astronomers determine the masses of the two stars with Newton's laws of motion.
In this fashion, the astronomers calculate that the newly discovered twins have nearly identical masses that 41 percent of the sun. According to current theories, mass and composition are the two factors that determine a star of the physical properties and dictate the entire life cycle. Since the two stars condensed from the same cloud of gas and dust they should have the same composition. With the same mass and composition, they should be identical in every respect. Thus, the astronomers surprised when they discovered that the twins showed significant differences in the brightness, surface temperature and possibly size.
The astronomers the first measurements of the eclipses of the two stars of sifting through almost 15 years worth of observations of several thousand stars with a telescope at the Kitt Peak National Observatory in Arizona and the SMARTS telescopes at the Cerro Tololo Inter-American Observatory in Chile. For more information about the two stars, they made additional measurements using the Hobby-Eberly Telescope in Texas. By measuring the difference in the amount that the light during the darkness, the astronomers were able to find that one of the stars is two times brighter than the others, calculated that the bright star has a surface temperature of 300 ° higher than its twin . An additional analysis of the light spectrum from the couple also pointed out that one of the stars is about 10 percent larger than the others, but further observations are needed to confirm.
"The easiest way to explain these differences is when a star was about 500000 years before his twin," says Stassun. "This is a human birth order difference of about half a day."
In addition to causing theorists to re-examine star formation models, the new discovery can lead to the astronomers to readjust their estimates of the masses and the age of thousands of young stars less than a few million years old. Current estimates are based on models that are calibrated with measurements of young stars that binary were presumed to have simultaneously. The recalibration may be required as much as 20 percent for the mass of a typical young stars and as much as 50 percent for very low-mass stars like brown dwarfs, Stassun estimates.
Other participants in the study are doctoral Phillip Cargile and Alicia Aarnio from Vanderbilt and Aaron Geller from the University of Wisconsin-Madison, together with Eric stamp at the University of St. Andrews in Scotland.
The twins were in the Orion Nebula, a well-known stellar nursery, which is 1500 light years away. The newly formed stars are about 1 million years old. With a full life of about 50 billion years, making it equivalent to 1-day-old human baby.
"Very young superpower binary files from it are the Rosetta stone to us about the history of life newly formed stars," says Keivan Stassun, Associate Professor of Astronomy at the University of Vanderbilt. He and Robert D. Mathieu from the University of Wisconsin-Madison initiated the project.
Superpower binaries are pairs of stars that revolve around an axis perpendicular to the direction to Earth. This orientation allows astronomers to determine the rate that the two stars orbit around each other-even if they can not resolve individual stars by measuring the periodic fluctuations in brightness, if the star pass against each other. With this information, the astronomers determine the masses of the two stars with Newton's laws of motion.
In this fashion, the astronomers calculate that the newly discovered twins have nearly identical masses that 41 percent of the sun. According to current theories, mass and composition are the two factors that determine a star of the physical properties and dictate the entire life cycle. Since the two stars condensed from the same cloud of gas and dust they should have the same composition. With the same mass and composition, they should be identical in every respect. Thus, the astronomers surprised when they discovered that the twins showed significant differences in the brightness, surface temperature and possibly size.
The astronomers the first measurements of the eclipses of the two stars of sifting through almost 15 years worth of observations of several thousand stars with a telescope at the Kitt Peak National Observatory in Arizona and the SMARTS telescopes at the Cerro Tololo Inter-American Observatory in Chile. For more information about the two stars, they made additional measurements using the Hobby-Eberly Telescope in Texas. By measuring the difference in the amount that the light during the darkness, the astronomers were able to find that one of the stars is two times brighter than the others, calculated that the bright star has a surface temperature of 300 ° higher than its twin . An additional analysis of the light spectrum from the couple also pointed out that one of the stars is about 10 percent larger than the others, but further observations are needed to confirm.
"The easiest way to explain these differences is when a star was about 500000 years before his twin," says Stassun. "This is a human birth order difference of about half a day."
In addition to causing theorists to re-examine star formation models, the new discovery can lead to the astronomers to readjust their estimates of the masses and the age of thousands of young stars less than a few million years old. Current estimates are based on models that are calibrated with measurements of young stars that binary were presumed to have simultaneously. The recalibration may be required as much as 20 percent for the mass of a typical young stars and as much as 50 percent for very low-mass stars like brown dwarfs, Stassun estimates.
Other participants in the study are doctoral Phillip Cargile and Alicia Aarnio from Vanderbilt and Aaron Geller from the University of Wisconsin-Madison, together with Eric stamp at the University of St. Andrews in Scotland.
Hungry Black Holes
The largest black holes could eat as well as the small ones, according to NASA's Chandra X-Ray Observatory and ground-based telescopes. This discovery supports the impact of Einstein's relativity theory that black holes of all sizes with similar characteristics, and will be useful for predicting the properties of a suspected new class of black holes.
The conclusion comes from a large campaign of observation of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that over 70 million times more massive than the sun, and generates energy and radiation as it moves gas in the central region of the galaxy to the inside at high speeds.
In contrast, the so-called stellar mass black holes, which is more than 10 times more massive than the sun, have a different food source. These smaller black holes acquire new material by drawing gas from the companion orbiting stars. Due to the large and small black holes exist in different environments with different sources of material to feed, a question remained whether they feed in the same way.
With these new observations and a detailed theoretical model, a team of researchers compared the characteristics of M81's black hole with the mass stellar black holes. The results show that either large or small, black holes indeed appear to eat like any other, and a similar distribution of X-rays, optical light and radio.
One of the effects of Einstein's theory of general relativity theory is that black holes are simply objects and their masses and spins determine their impact on the space-time. The latest research results suggest that this simplicity manifests itself despite complicated effects on the environment.
"This confirms that the feeding patterns for black holes of different sizes can be very similar," says Sera Markoff of the Astronomical Institute of the University of Amsterdam in the Netherlands, led the study. "We thought that was the case, but until now we have not been able to nail."
The model that Markoff and her colleagues used to the black holes includes a silent disk of material spinning around the black hole. This structure would mainly produce X-rays and optical light. A region of hot gas around the black hole would be seen largely UV and X-ray light. A major contribution to the radio and X-ray light comes from jets, by the black hole. Multi-wavelength data is necessary to separate these overlapping light sources.
"If we look at the data, it appears that our model works equally well for the huge black hole in M81 as for the smaller guys," said Michael Nowak, a co-author from the Massachusetts Institute of Technology. "Everything about this huge black hole looks the same unless it is almost 10 million times greater."
Among actively feeding the black hole in M81 is one of the dimmest, probably because it is "undernourished". However, it is one of the brightest as seen from Earth because of the relative proximity, so that high-quality observations.
"It seems as if the undernourished Black holes are the easiest in practice, perhaps because we can see, closer to the black hole," says Andrew Young from the University of Bristol in England. "They seem not to care too much get where their food."
This work should be useful for predicting the properties of a third, unconfirmed class called intermediate mass black holes with masses lie between those of the stellar and supermassive black holes. Some possible members of this class have been identified, but the evidence is controversial, so that specific forecasts for the properties of these black holes should be very helpful.
In addition to Chandra, three radio arrays (the Giant Meter Wave Radio Telescope, the Very Large Array and the Very Long Baseline Array), two millimeter telescopes (the Plateau de Bure interferometer and the Submillimeter Array) and Lick Observatory in the optics used to Monitoring of the M81. These observations were at the same time to ensure that brightness fluctuations due to changes in feeding rates are not confuse the results. Chandra X-ray is the only satellite able to isolate the soft X-rays of the black hole from the issuance of the rest of the galaxy.
This result confirmed earlier less detailed work by Andrea Merloni from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and colleagues that suggested that the basic characteristics of larger black holes are similar to the small ones. Their study was not to simultaneous multi-wavelength observations nor the application of a detailed physical model.
The conclusion comes from a large campaign of observation of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that over 70 million times more massive than the sun, and generates energy and radiation as it moves gas in the central region of the galaxy to the inside at high speeds.
In contrast, the so-called stellar mass black holes, which is more than 10 times more massive than the sun, have a different food source. These smaller black holes acquire new material by drawing gas from the companion orbiting stars. Due to the large and small black holes exist in different environments with different sources of material to feed, a question remained whether they feed in the same way.
With these new observations and a detailed theoretical model, a team of researchers compared the characteristics of M81's black hole with the mass stellar black holes. The results show that either large or small, black holes indeed appear to eat like any other, and a similar distribution of X-rays, optical light and radio.
One of the effects of Einstein's theory of general relativity theory is that black holes are simply objects and their masses and spins determine their impact on the space-time. The latest research results suggest that this simplicity manifests itself despite complicated effects on the environment.
"This confirms that the feeding patterns for black holes of different sizes can be very similar," says Sera Markoff of the Astronomical Institute of the University of Amsterdam in the Netherlands, led the study. "We thought that was the case, but until now we have not been able to nail."
The model that Markoff and her colleagues used to the black holes includes a silent disk of material spinning around the black hole. This structure would mainly produce X-rays and optical light. A region of hot gas around the black hole would be seen largely UV and X-ray light. A major contribution to the radio and X-ray light comes from jets, by the black hole. Multi-wavelength data is necessary to separate these overlapping light sources.
"If we look at the data, it appears that our model works equally well for the huge black hole in M81 as for the smaller guys," said Michael Nowak, a co-author from the Massachusetts Institute of Technology. "Everything about this huge black hole looks the same unless it is almost 10 million times greater."
Among actively feeding the black hole in M81 is one of the dimmest, probably because it is "undernourished". However, it is one of the brightest as seen from Earth because of the relative proximity, so that high-quality observations.
"It seems as if the undernourished Black holes are the easiest in practice, perhaps because we can see, closer to the black hole," says Andrew Young from the University of Bristol in England. "They seem not to care too much get where their food."
This work should be useful for predicting the properties of a third, unconfirmed class called intermediate mass black holes with masses lie between those of the stellar and supermassive black holes. Some possible members of this class have been identified, but the evidence is controversial, so that specific forecasts for the properties of these black holes should be very helpful.
In addition to Chandra, three radio arrays (the Giant Meter Wave Radio Telescope, the Very Large Array and the Very Long Baseline Array), two millimeter telescopes (the Plateau de Bure interferometer and the Submillimeter Array) and Lick Observatory in the optics used to Monitoring of the M81. These observations were at the same time to ensure that brightness fluctuations due to changes in feeding rates are not confuse the results. Chandra X-ray is the only satellite able to isolate the soft X-rays of the black hole from the issuance of the rest of the galaxy.
This result confirmed earlier less detailed work by Andrea Merloni from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and colleagues that suggested that the basic characteristics of larger black holes are similar to the small ones. Their study was not to simultaneous multi-wavelength observations nor the application of a detailed physical model.
Selasa, 24 Juni 2008
Quantum Gravity - Revealed By Gamma Ray Bursts?
Gamma-ray bursts - the grand and mysterious flashes of high energy light now as probes for the most ranges from the earliest moments of the universe and time - may be another secret to reveal: quantum gravity.
Not yet observed in nature, the quantum gravity is the long sought missing link between Einstein's general theory of relativity and quantum mechanics, the two pillars of modern physics inappropriate. NASA's Gamma-ray Large Area Space Telescope (GLAST), scheduled for a 2005 start may be able to identify for the first time the effects of quantum gravity in the speed of gamma-ray burst photons, after two NASA scientists.
The main message is that the gamma-ray bursts that GLAST are discovered and removed sufficiently strong enough to see the highest of the high energy photons travel a little slower than at lower-energy photons, weighted by the effect of quantum gravity.
Drs Jay Norris and Jerry Bonnell of the NASA Goddard Space Flight Center, the math. The two observed, astronomers said that only time will tell whether this delay GLAST is the time to quantum gravity (and the figures, go with it) is still very speculative.
A gamma-ray burst is the largest outpouring of energy the universe has ever seen, apart from the "Big Bang". Each burst is as powerful as a billion trillion suns and satellite recognize burst or two per day. As usual the burst, but nobody is sure about what it means. They are only in the gamma-ray wave range, although their afterglows abate slowly into the x-ray and optical realm.
Gamma-ray bursts were discovered in the late 1960s, decades after the concepts of the general theory of relativity and quantum physics spiced the first lexicon.
General Relativity accounts for gravity, the force that acts in large scales. Quantum mechanics, part of the standard model, describes the behavior of the other three fundamental forces: electromagnetism and weak forces (in radioactive decay) and strong forces (holding subatomic particles together). These three forces act on small scales, and each has a particle, which transmits power: namely, photons (electromagnetism), gluons (for strong forces) and W and Z particles (for strong forces).
The hypothesis that the particles would provide for the force of gravity, the graviton. Well, a graviton is not something that you're looking for in a huge particle accelerator, as opposed to a Higgs boson or other exotic particles. The scientists are looking for, rather than the impact of Graviton, as in gravitational waves rocking chair objects in space or in the case of the Gamma-Ray Burst, gravitons slowing of a passing photon.
In quantum mechanics, the vacuum of space is no vacuum, but it is on the spot by virtual particles, such as the graviton. Light through this field of virtual particles is broken, just as it is, if the water or through any medium.
The Graviton that the nature of gravitational force, would interact with (or slow down) the particles with a greater gravitational potential. With mass directly proportional to the energy, as in E = mc2, higher energy photons have a greater gravitational potential than to lower energy photons - as if they weigh more.
The highest energy photons would therefore travel through space more slowly than lower-energy photons. (This does not violate the constancy of the speed of light, for light travels in the same speed only in an absolute vacuum.) To demonstrate the very slight difference in the photons speed, you need a very distant source emitting very high energy photons: that is , The gamma ray burst.
Last year, Dr. Bradley Schaefer of the University of Texas tested the consistency of the speed of light to great accuracy, with both high-and low-photons, and found no change in time. The photons in the main proceedings in question Norris and Bonnell analysis, though, are of higher energy than anything previously studied.
When it comes to burst photons, GLAST will determine the highest of the high. The instrument would be able to detect photons of gamma-ray bursts with energy thousands of times higher than those in Burst acknowledged that the missions before GLAST, as HETE-2 and SWIFT. Also, with the source of the gamma ray burst probably billions of light years away, GLAST might be a delay in photon arrival times as they travel through the endless soup of gravitons.
Such a scenario would be a strong evidence for the presence of the graviton and thus, the concept of quantum gravity. Of course, the quantum gravity is as speculative as it is, obviously delays in photons speed might have some astronomers zuzubilligen that this is the dynamics of the explosion and not the medium of space. However, the discovery of the LAG times is a deep revelation.
Several groups of scientists working on the issue of quantum gravity and how to recognize. A team led by Dr. John Ellis of CERN is looking at low-energy gamma-ray bursts, Dr. Karl Mannheim university observatory and his group are seeking high energy photons detected earlier burst, and a group headed by Dr .. TC Weekes the Whipple Observatory in Arizona is pouring through the data of the highest detected gamma-ray photons, from relatively nearby galaxies with active black holes.
Eindeutigen evidence of quantum gravity would ultimately open up new avenues for physicists' ultimate goal the unification of all four fundamental forces in the framework of a Grand Unified Theory - a theory states that the behavior of all matter and energy in all situations.
Not yet observed in nature, the quantum gravity is the long sought missing link between Einstein's general theory of relativity and quantum mechanics, the two pillars of modern physics inappropriate. NASA's Gamma-ray Large Area Space Telescope (GLAST), scheduled for a 2005 start may be able to identify for the first time the effects of quantum gravity in the speed of gamma-ray burst photons, after two NASA scientists.
The main message is that the gamma-ray bursts that GLAST are discovered and removed sufficiently strong enough to see the highest of the high energy photons travel a little slower than at lower-energy photons, weighted by the effect of quantum gravity.
Drs Jay Norris and Jerry Bonnell of the NASA Goddard Space Flight Center, the math. The two observed, astronomers said that only time will tell whether this delay GLAST is the time to quantum gravity (and the figures, go with it) is still very speculative.
A gamma-ray burst is the largest outpouring of energy the universe has ever seen, apart from the "Big Bang". Each burst is as powerful as a billion trillion suns and satellite recognize burst or two per day. As usual the burst, but nobody is sure about what it means. They are only in the gamma-ray wave range, although their afterglows abate slowly into the x-ray and optical realm.
Gamma-ray bursts were discovered in the late 1960s, decades after the concepts of the general theory of relativity and quantum physics spiced the first lexicon.
General Relativity accounts for gravity, the force that acts in large scales. Quantum mechanics, part of the standard model, describes the behavior of the other three fundamental forces: electromagnetism and weak forces (in radioactive decay) and strong forces (holding subatomic particles together). These three forces act on small scales, and each has a particle, which transmits power: namely, photons (electromagnetism), gluons (for strong forces) and W and Z particles (for strong forces).
The hypothesis that the particles would provide for the force of gravity, the graviton. Well, a graviton is not something that you're looking for in a huge particle accelerator, as opposed to a Higgs boson or other exotic particles. The scientists are looking for, rather than the impact of Graviton, as in gravitational waves rocking chair objects in space or in the case of the Gamma-Ray Burst, gravitons slowing of a passing photon.
In quantum mechanics, the vacuum of space is no vacuum, but it is on the spot by virtual particles, such as the graviton. Light through this field of virtual particles is broken, just as it is, if the water or through any medium.
The Graviton that the nature of gravitational force, would interact with (or slow down) the particles with a greater gravitational potential. With mass directly proportional to the energy, as in E = mc2, higher energy photons have a greater gravitational potential than to lower energy photons - as if they weigh more.
The highest energy photons would therefore travel through space more slowly than lower-energy photons. (This does not violate the constancy of the speed of light, for light travels in the same speed only in an absolute vacuum.) To demonstrate the very slight difference in the photons speed, you need a very distant source emitting very high energy photons: that is , The gamma ray burst.
Last year, Dr. Bradley Schaefer of the University of Texas tested the consistency of the speed of light to great accuracy, with both high-and low-photons, and found no change in time. The photons in the main proceedings in question Norris and Bonnell analysis, though, are of higher energy than anything previously studied.
When it comes to burst photons, GLAST will determine the highest of the high. The instrument would be able to detect photons of gamma-ray bursts with energy thousands of times higher than those in Burst acknowledged that the missions before GLAST, as HETE-2 and SWIFT. Also, with the source of the gamma ray burst probably billions of light years away, GLAST might be a delay in photon arrival times as they travel through the endless soup of gravitons.
Such a scenario would be a strong evidence for the presence of the graviton and thus, the concept of quantum gravity. Of course, the quantum gravity is as speculative as it is, obviously delays in photons speed might have some astronomers zuzubilligen that this is the dynamics of the explosion and not the medium of space. However, the discovery of the LAG times is a deep revelation.
Several groups of scientists working on the issue of quantum gravity and how to recognize. A team led by Dr. John Ellis of CERN is looking at low-energy gamma-ray bursts, Dr. Karl Mannheim university observatory and his group are seeking high energy photons detected earlier burst, and a group headed by Dr .. TC Weekes the Whipple Observatory in Arizona is pouring through the data of the highest detected gamma-ray photons, from relatively nearby galaxies with active black holes.
Eindeutigen evidence of quantum gravity would ultimately open up new avenues for physicists' ultimate goal the unification of all four fundamental forces in the framework of a Grand Unified Theory - a theory states that the behavior of all matter and energy in all situations.
Quintessence, Accelerating The Universe?
When it doubt, go back to the basics. That is exactly what cosmologists have to explain why our universe seems to be accelerating.
The new buzzword in cosmology these days is "quintessence", borrowed from the ancient Greeks used the term to describe a mysterious "Fifth Element" - in addition to air, earth, fire and water - in the possession of the moon and stars in Place. Quintessence, some cosmologists say, is an exotic kind of energy field that pushes particles apart, overwhelming gravity and the other fundamental forces.
If quintessence is real, it would not be rare. Two-thirds of the universe would be the stuff. In the Texas Symposium on Relativistic Astrophysics in Austin, Paul Steinhardt of Princeton University, explained how the bottom line was dominant force in the universe a few billion years old, in a relatively short time, he says. Steinhardt not exactly warm on the set with his new theory.
Cosmology used to a quiet life. As recent as two years ago, most people were in agreement that, yes, the universe is expanding. In question was only whether the expansion would come slowly to a halt, and the universe falls back into itself, or whether the universe continue to float apart, but at a slower and slower. If there is enough matter in the universe, then gravity would halt the expansion and suck all know that we in the "big crunch". All cosmologists had to do was to add up the mass in the universe.
But in 1998, cosmologists were shaken from their seats by the discovery that the universe is expanding at an astonishing rate. New and Improved observations of distant supernovae have been rendering of the 'Big Crunch' question null and void.
Supernovae are stars explosions, and there are a few varieties. One, the so-called Type Ia supernovae, exploding with a characteristic energy. With a decent idea of the explosion and the absolute apparent brightness, astronomers determine the distance that these objects. Then know the redshift, they can calculate how fast the supernovae are away from us. If it is found that the most distant Type 1a supernovae have gone much faster then closer, suggesting that the universe's expansion is actually accelerating, not slowing down.
There are a few non-believers, with good reason. Some say that the most distant supernovae May only far (that is, dim), because the intervening dust dispersed its light. Also, we can not be sure that the most distant supernovae explode in the same way as closer.
Most cosmologists, however, have hopped on the train speeding universe. Their task now is to explain how they can be physically possible. Should not the force of gravity, the great attractor, hold the universe of Flying apart?
Einstein thought about, but for the wrong reason. He developed a Fudge factor called the cosmological constant. Einstein, and all others in the early 20th Century, thought the universe was static and that everything was within the Milky Way. The cosmological constant was an anti-gravity "vacuum" force to hold that gravity pulls from the universe. By 1930, Edwin Hubble discovered that the Milky Way was just one of a multitude of galaxies and that the universe is expanding. So there was no longer a need for a cosmological constant. Einstein, the number of his equations, he calls his "biggest mistake".
The problem with the cosmological constant, Steinhardt says, is that there is indeed constant. It provides the same force in the entire period. Observational evidence indicates that regardless of this force is that the acceleration of the universe, it was not constant over time. It had periods in which the power was negligible, because planets and stars and stripes squirrels never had.
"The cosmological constant is a very specific form of energy, a vacuum energy," Steinhardt said. "Quintessence covers a wide class of possibilities. It is a dynamic, temporally and spatially dependent developing form of energy with negative pressure sufficient to increase the pace of expansion."
Vacuum energy is the energy potential in an absolute vacuum, without the matter or radiation. Think of a chimney suck air from the living room, that's the universe of matter expanding into the great unknown. Quintessence is a quantum with both kinetic and potential energy. Depending on the relationship of both energy and the pressure they exert quintessence can either attract or repel.
Quintessence was to be expected, with around 10 billion years, according to the theory. That may be fairly early in a 15 billion years old universe, but cosmologist not see it. The dark energy was created when the universe 10-35 seconds old, they do not cause the universe to speed for another five billion years. That is a factor of more than 1050 - and in a relatively short time in terms of the redshift and the size of the universe.
Steinhardt quintessence indicates that during the transition from a radiation on matter-dominated universe when it cool enough for atoms and finally to form stars.
But what is quintessence? Nobody knows. Radiation, normal matter and dark matter probably all have positive pressure. They have therefore a gravitationally attractive force. Everything with negative pressure, the general theory of relativity dictates, would have a gravitationally repulsive force.
In essence, the quantum would have a very long wavelength of the size of the universe. His kinetic energy depends on the rate of vibrations in the field strength, its potential energy depends on the interaction of the field with matter. The more kinetic energy, the more positive pressure - that is not so likely to a universe long wavelength. So for the moment, potential energy and lower pressures. Therefore quintessence is a repulsive force.
This may change, says Steinhardt. Quintessence interaction with matter and evolves over time. Quintessence decay can also be used in new forms of hot matter or radiation. We are not necessarily doomed to a universe expands, that forever, which is every atom from here to infinity.
Sounds nice, but not everyone is sold.
"The theory of the universe is accelerating a work in progress," said James Peebles, professor emeritus at Princeton University. "I admire the architecture, but I do not want to move in just yet."
Namely, on the Texas Symposium, polite arguments over quintessence stretched well into the next interview. Some suggested that the nature of dark energy would become clear with a better understanding of gravity and gravitational waves. Steinhardt was admittedly at a loss with some of the questions. Astronomers and cosmologists are fascinated by quintessence, they simply need more information.
We will not be able to keep quintessence in our hands, nor can we probes to detect them directly. At best, we need tools, may find that the effect of the quintessence of the universe over time. Two space science missions are promising, said Steinhardt.
The Supernova Acceleration Project (SNAP) would systematically search for a large number of distant supernovae, beyond the reach of most space telescopes. Saul Perlmutter of Lawrence Berkeley National Laboratory, said, including in the Texas meeting, the efforts and described a not so complicated satellite with a two-metre telescope to search for supernovae at high redshift. SNAP would find about 2000 supernovae per year, enough to significantly close the error in bars calculations of the universe is expanding. The mission has not yet been funded.
Closer to the realization is Microwave Anisotropy Probe (MAP). It can detect small variations in the amount of quintessence of the sky as waves in the microwave background radiation remaining from when the universe was 300000 years old. Chuck Bennett, a MAP project manager at NASA Goddard Space Flight Center, is pretty excited.
"MAP is the best way to test quintessence in the immediate future," said Bennett. "Quintessence makes very specific predictions. To see if it is there or not is a non-brainer. To make a precise value, well, that's a bit more difficult."
At issue is how well the card can measure the quintessential factors in the equation, as the mass density of the universe, its geometry and the speed of expansion and the neutrino contribution.
Steinhardt certainly has a good track record. He was one of the originators of the theory of inflation and the acceleration predicts a universe in 1995. If quintessence has turned into something that scientists can sink their teeth into, it would be yet another confirmation of Einstein's theories, and a fine nod to the ancient Greeks, sent us this way.
The new buzzword in cosmology these days is "quintessence", borrowed from the ancient Greeks used the term to describe a mysterious "Fifth Element" - in addition to air, earth, fire and water - in the possession of the moon and stars in Place. Quintessence, some cosmologists say, is an exotic kind of energy field that pushes particles apart, overwhelming gravity and the other fundamental forces.
If quintessence is real, it would not be rare. Two-thirds of the universe would be the stuff. In the Texas Symposium on Relativistic Astrophysics in Austin, Paul Steinhardt of Princeton University, explained how the bottom line was dominant force in the universe a few billion years old, in a relatively short time, he says. Steinhardt not exactly warm on the set with his new theory.
Cosmology used to a quiet life. As recent as two years ago, most people were in agreement that, yes, the universe is expanding. In question was only whether the expansion would come slowly to a halt, and the universe falls back into itself, or whether the universe continue to float apart, but at a slower and slower. If there is enough matter in the universe, then gravity would halt the expansion and suck all know that we in the "big crunch". All cosmologists had to do was to add up the mass in the universe.
But in 1998, cosmologists were shaken from their seats by the discovery that the universe is expanding at an astonishing rate. New and Improved observations of distant supernovae have been rendering of the 'Big Crunch' question null and void.
Supernovae are stars explosions, and there are a few varieties. One, the so-called Type Ia supernovae, exploding with a characteristic energy. With a decent idea of the explosion and the absolute apparent brightness, astronomers determine the distance that these objects. Then know the redshift, they can calculate how fast the supernovae are away from us. If it is found that the most distant Type 1a supernovae have gone much faster then closer, suggesting that the universe's expansion is actually accelerating, not slowing down.
There are a few non-believers, with good reason. Some say that the most distant supernovae May only far (that is, dim), because the intervening dust dispersed its light. Also, we can not be sure that the most distant supernovae explode in the same way as closer.
Most cosmologists, however, have hopped on the train speeding universe. Their task now is to explain how they can be physically possible. Should not the force of gravity, the great attractor, hold the universe of Flying apart?
Einstein thought about, but for the wrong reason. He developed a Fudge factor called the cosmological constant. Einstein, and all others in the early 20th Century, thought the universe was static and that everything was within the Milky Way. The cosmological constant was an anti-gravity "vacuum" force to hold that gravity pulls from the universe. By 1930, Edwin Hubble discovered that the Milky Way was just one of a multitude of galaxies and that the universe is expanding. So there was no longer a need for a cosmological constant. Einstein, the number of his equations, he calls his "biggest mistake".
The problem with the cosmological constant, Steinhardt says, is that there is indeed constant. It provides the same force in the entire period. Observational evidence indicates that regardless of this force is that the acceleration of the universe, it was not constant over time. It had periods in which the power was negligible, because planets and stars and stripes squirrels never had.
"The cosmological constant is a very specific form of energy, a vacuum energy," Steinhardt said. "Quintessence covers a wide class of possibilities. It is a dynamic, temporally and spatially dependent developing form of energy with negative pressure sufficient to increase the pace of expansion."
Vacuum energy is the energy potential in an absolute vacuum, without the matter or radiation. Think of a chimney suck air from the living room, that's the universe of matter expanding into the great unknown. Quintessence is a quantum with both kinetic and potential energy. Depending on the relationship of both energy and the pressure they exert quintessence can either attract or repel.
Quintessence was to be expected, with around 10 billion years, according to the theory. That may be fairly early in a 15 billion years old universe, but cosmologist not see it. The dark energy was created when the universe 10-35 seconds old, they do not cause the universe to speed for another five billion years. That is a factor of more than 1050 - and in a relatively short time in terms of the redshift and the size of the universe.
Steinhardt quintessence indicates that during the transition from a radiation on matter-dominated universe when it cool enough for atoms and finally to form stars.
But what is quintessence? Nobody knows. Radiation, normal matter and dark matter probably all have positive pressure. They have therefore a gravitationally attractive force. Everything with negative pressure, the general theory of relativity dictates, would have a gravitationally repulsive force.
In essence, the quantum would have a very long wavelength of the size of the universe. His kinetic energy depends on the rate of vibrations in the field strength, its potential energy depends on the interaction of the field with matter. The more kinetic energy, the more positive pressure - that is not so likely to a universe long wavelength. So for the moment, potential energy and lower pressures. Therefore quintessence is a repulsive force.
This may change, says Steinhardt. Quintessence interaction with matter and evolves over time. Quintessence decay can also be used in new forms of hot matter or radiation. We are not necessarily doomed to a universe expands, that forever, which is every atom from here to infinity.
Sounds nice, but not everyone is sold.
"The theory of the universe is accelerating a work in progress," said James Peebles, professor emeritus at Princeton University. "I admire the architecture, but I do not want to move in just yet."
Namely, on the Texas Symposium, polite arguments over quintessence stretched well into the next interview. Some suggested that the nature of dark energy would become clear with a better understanding of gravity and gravitational waves. Steinhardt was admittedly at a loss with some of the questions. Astronomers and cosmologists are fascinated by quintessence, they simply need more information.
We will not be able to keep quintessence in our hands, nor can we probes to detect them directly. At best, we need tools, may find that the effect of the quintessence of the universe over time. Two space science missions are promising, said Steinhardt.
The Supernova Acceleration Project (SNAP) would systematically search for a large number of distant supernovae, beyond the reach of most space telescopes. Saul Perlmutter of Lawrence Berkeley National Laboratory, said, including in the Texas meeting, the efforts and described a not so complicated satellite with a two-metre telescope to search for supernovae at high redshift. SNAP would find about 2000 supernovae per year, enough to significantly close the error in bars calculations of the universe is expanding. The mission has not yet been funded.
Closer to the realization is Microwave Anisotropy Probe (MAP). It can detect small variations in the amount of quintessence of the sky as waves in the microwave background radiation remaining from when the universe was 300000 years old. Chuck Bennett, a MAP project manager at NASA Goddard Space Flight Center, is pretty excited.
"MAP is the best way to test quintessence in the immediate future," said Bennett. "Quintessence makes very specific predictions. To see if it is there or not is a non-brainer. To make a precise value, well, that's a bit more difficult."
At issue is how well the card can measure the quintessential factors in the equation, as the mass density of the universe, its geometry and the speed of expansion and the neutrino contribution.
Steinhardt certainly has a good track record. He was one of the originators of the theory of inflation and the acceleration predicts a universe in 1995. If quintessence has turned into something that scientists can sink their teeth into, it would be yet another confirmation of Einstein's theories, and a fine nod to the ancient Greeks, sent us this way.
String Theory, The Ultimate Theory?
In the standard model of particle physics, particles are as points move through space, the pursuit of a line with the name "World online. To take account of the different interactions in nature observed, the particles with more degree of freedom to their position and velocity, such as mass, electric charge, color (this is the "cargo" in conjunction with the strong interaction) or spin.
The standard model has been in a framework, known as Quantum Field Theory (QFT), which gives us the tools to build both in line with theories of quantum mechanics and special relativity theory. With these tools, theories have been built, describing with great success three of the four known interactions in nature: electromagnetism and the strong and weak nuclear forces.
It was a very successful agreement between electromagnetism and the weak force has been reached (electric Weak theory), and promising ideas put forward to try to strong force. But unfortunately the fourth interaction, gravity, as defined by Einstein's General Theory of Relativity (GR), does not seem to fit into this scheme. Whenever you try to apply the rules of
QFT GR to get results that make no sense.
The usual areas of the general theory of relativity and quantum mechanics are quite different. General relativity theory describes gravity and thus is usually limited to the largest and structures, including the massive stars, galaxies, black holes and even in cosmology, the universe itself quantum mechanics is very relevant in the description of the smallest structures in the
universe, such as Electrons and quarks.
In most normal physical situations, either general theory of relativity and quantum mechanics is a prerequisite for a theoretical understanding, but not both. However, there are extreme physical conditions, which require these two fundamental theories for an adequate theoretical treatment.
Prime examples of such situations are space-time singularities, as the central point of a black hole or the state of the universe shortly before the Big Bang. These exotic physical structures with enormous mass scale (and thus the general theory of relativity) and extremely small distance scales (quantum mechanics).
Unfortunately, the general theory of relativity and quantum mechanics are not compatible: any calculation, which also uses these two instruments, and the income nonsensical answers. The origin of this problem can be attributed to equations, which are badly behaved when particles interact with each other minutes scales in the order of 10-33cm - the Planck length.
Another problem with this model is that you assume that the existence of different forces and their carriers. Einstein hoped that a "unified" theory in which all the known forces would be composed of one single in a certain way. Electricity and magnetism used to be thought of as two forces, but now we know these are two different aspects of the same (electro-magnetic). Could the same kind of agreement to hold the four forces, which today are distinguishable?
String theory is currently the most promising example of a candidate unified theory. We do not yet know whether it correctly describes nature, but it seems to be a theory, largely describes a world similar to ours, and is endowed with beauty and consistency to an astonishing degree.
Strings
The physical idea is very simple. Instead of many types of point-like elementary particles, physicists postulate that in nature there are a number of individual string object. The string is not "everything" but it is a very simple and other things are made. As for the musical strings, this basic string can vibrate, and each vibration mode can be used as point-like elementary particles, as well as the Modes of a musical string perceived as their own notes!
String theory solves the problem of deep incompatibility of the two fundamental theories (GR and QFT) by modifying the properties of the general theory of relativity, if it scales in the order of the Planck length. Modern accelerator can only probe scales at a distance about 10-16cm, and thus these loops of string instruments seem to be objects.
However, the string theoretical hypothesis that they actually are tiny loops, dramatically changes the way in which these objects interact in the shortest distance from scales. This modification is allowed, what the gravity and quantum mechanics into a harmonious unit.
There is a price to pay for this solution, however. It turns out that the equations of string theory are self-consistent only if the universe contains, in addition to the time, nine spatial dimensions. Since the gross conflict with the perception of three-dimensional space, it might seem that string theory must be discarded. However, this is not true.
Several theories String
However, it is more than a theory. These theories are classified, depending on whether or not the strings are required closed loop, and whether the particles range fermions (particles, does matter). To fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particles that transmits a force), there is a fermion. So does the supersymmetry particles, the forces to the particles that make up matter.
String Theory, which deals with bosons are not only more popular because they require 26 space-time dimensions and a particle with imaginary mass of the tachyon. There are a whole series of superstring theory, which is mathematically only require the ten dimensions. A few of the differences between them are closed-loop theories and others only with closed loop, the pause in open strings.
Massless theories with fermions only spinning one way (chiral) and string theories, the heterotic, which means the right and left moving strings. Different combinations of the above characteristics make us with 5 plausible (mathematically) theories.
M-theory
There was a difficulty in the investigation of these theories: physicists and mathematicians do not have instruments to the theories of all possible values of the parameters in the theories. Each theory was like a big planet, which we knew only a small island somewhere on the planet. But over the last four years, techniques have been developed to the theories more thoroughly, in other words, to travel around the lake in each of these planets and find new islands. And only then became clear that these five string theories are actually islands on the same planet and not different! There is an underlying theory of string that all theories are just different aspects. This was called M-theory.
One of the islands was found that in the M-theory planet corresponds to a theory that life is not at 10 but in 11 dimensions. This seems to be telling us that M-theory should than 11 dimensional theory that a 10 dimensional in some points in their area of parameters. Such a theory could have as a fundamental goal of a membrane, in contrast to a string. Like a drinking straw seen at a distance, the membranes would look like if we strings curl 11 Dimension in a small circle.
The standard model has been in a framework, known as Quantum Field Theory (QFT), which gives us the tools to build both in line with theories of quantum mechanics and special relativity theory. With these tools, theories have been built, describing with great success three of the four known interactions in nature: electromagnetism and the strong and weak nuclear forces.
It was a very successful agreement between electromagnetism and the weak force has been reached (electric Weak theory), and promising ideas put forward to try to strong force. But unfortunately the fourth interaction, gravity, as defined by Einstein's General Theory of Relativity (GR), does not seem to fit into this scheme. Whenever you try to apply the rules of
QFT GR to get results that make no sense.
The usual areas of the general theory of relativity and quantum mechanics are quite different. General relativity theory describes gravity and thus is usually limited to the largest and structures, including the massive stars, galaxies, black holes and even in cosmology, the universe itself quantum mechanics is very relevant in the description of the smallest structures in the
universe, such as Electrons and quarks.
In most normal physical situations, either general theory of relativity and quantum mechanics is a prerequisite for a theoretical understanding, but not both. However, there are extreme physical conditions, which require these two fundamental theories for an adequate theoretical treatment.
Prime examples of such situations are space-time singularities, as the central point of a black hole or the state of the universe shortly before the Big Bang. These exotic physical structures with enormous mass scale (and thus the general theory of relativity) and extremely small distance scales (quantum mechanics).
Unfortunately, the general theory of relativity and quantum mechanics are not compatible: any calculation, which also uses these two instruments, and the income nonsensical answers. The origin of this problem can be attributed to equations, which are badly behaved when particles interact with each other minutes scales in the order of 10-33cm - the Planck length.
Another problem with this model is that you assume that the existence of different forces and their carriers. Einstein hoped that a "unified" theory in which all the known forces would be composed of one single in a certain way. Electricity and magnetism used to be thought of as two forces, but now we know these are two different aspects of the same (electro-magnetic). Could the same kind of agreement to hold the four forces, which today are distinguishable?
String theory is currently the most promising example of a candidate unified theory. We do not yet know whether it correctly describes nature, but it seems to be a theory, largely describes a world similar to ours, and is endowed with beauty and consistency to an astonishing degree.
Strings
The physical idea is very simple. Instead of many types of point-like elementary particles, physicists postulate that in nature there are a number of individual string object. The string is not "everything" but it is a very simple and other things are made. As for the musical strings, this basic string can vibrate, and each vibration mode can be used as point-like elementary particles, as well as the Modes of a musical string perceived as their own notes!
String theory solves the problem of deep incompatibility of the two fundamental theories (GR and QFT) by modifying the properties of the general theory of relativity, if it scales in the order of the Planck length. Modern accelerator can only probe scales at a distance about 10-16cm, and thus these loops of string instruments seem to be objects.
However, the string theoretical hypothesis that they actually are tiny loops, dramatically changes the way in which these objects interact in the shortest distance from scales. This modification is allowed, what the gravity and quantum mechanics into a harmonious unit.
There is a price to pay for this solution, however. It turns out that the equations of string theory are self-consistent only if the universe contains, in addition to the time, nine spatial dimensions. Since the gross conflict with the perception of three-dimensional space, it might seem that string theory must be discarded. However, this is not true.
Several theories String
However, it is more than a theory. These theories are classified, depending on whether or not the strings are required closed loop, and whether the particles range fermions (particles, does matter). To fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particles that transmits a force), there is a fermion. So does the supersymmetry particles, the forces to the particles that make up matter.
String Theory, which deals with bosons are not only more popular because they require 26 space-time dimensions and a particle with imaginary mass of the tachyon. There are a whole series of superstring theory, which is mathematically only require the ten dimensions. A few of the differences between them are closed-loop theories and others only with closed loop, the pause in open strings.
Massless theories with fermions only spinning one way (chiral) and string theories, the heterotic, which means the right and left moving strings. Different combinations of the above characteristics make us with 5 plausible (mathematically) theories.
M-theory
There was a difficulty in the investigation of these theories: physicists and mathematicians do not have instruments to the theories of all possible values of the parameters in the theories. Each theory was like a big planet, which we knew only a small island somewhere on the planet. But over the last four years, techniques have been developed to the theories more thoroughly, in other words, to travel around the lake in each of these planets and find new islands. And only then became clear that these five string theories are actually islands on the same planet and not different! There is an underlying theory of string that all theories are just different aspects. This was called M-theory.
One of the islands was found that in the M-theory planet corresponds to a theory that life is not at 10 but in 11 dimensions. This seems to be telling us that M-theory should than 11 dimensional theory that a 10 dimensional in some points in their area of parameters. Such a theory could have as a fundamental goal of a membrane, in contrast to a string. Like a drinking straw seen at a distance, the membranes would look like if we strings curl 11 Dimension in a small circle.
Radio Astronomy
It is surprising that many people, radio astronomy not be heard for ET phone home. SETI (the Search for Extraterrestrial Intelligence), a relatively small part of radio astronomy. It seems that the public perception of radio astronomy conjures up images of astronomers in tight jeans wear headphones to see some weak signal buried in the galactic noise. If we have a brief reality check, we find that radio astronomy is similar to optical astronomy telescopes in this (instruments that detect, image and enlarge) are used to observe the cosmos.
The difference is that while optical telescopes present images that are familiar in composition (ie the images on frequencies that we can see directly). Radio telescopes to observe the cosmos much lower frequencies. Most of us have seen the spectacular images acquired by the Hubble Space Telescope. To be sure these images not only give us an insight into the wonders of the universe, but move us in spirit by a sense of awe. Unfortunately, the primary sensory cells input device for us humans (eyes) is very limited "bandwidth" (the range of electromagnetic frequencies, or "colors" to which it is sensitive), and although the images move us, they do not give up their secrets easily . As a result, much of what happens in the universe is hidden from our view.
To put it simply, every color is a different frequency, and most of the color, with the range of the cosmos is painted is invisible to our eyes. It only makes sense, our sensitivity, the instrumentation, on the other frequencies of the electromagnetic spectrum. The radio telescope is one of those instruments. It allows us to monitor and the image of the universe at frequencies below our visual capabilities, which shows much of what is going on in the universe. Because certain frequencies pass easily through annoying dust and gas clouds, we can now study until now blocked objects from our point of view. Also, because certain gases, molecules and materials in the universe either emit or absorb light to radio frequencies, these structures can be viewed by the radio telescope. This feature not only allows the viewer to the image of these objects, but also allows the observers to collect much more information such as composition, speed, temperature and mass.
The range of frequencies, the spectrum is immense, so that the diversity and the types of instruments that make up radio telescopes is diverse in terms of design, size and configuration. Lower frequency (10 MHz - 100 MHz (wavelengths of 30 meters to 3 meters)) instruments are usually arrays of antennas similar to "TV antennas or are stationary reflectors of gigantic proportions with moveable nodes some are over 30 Meters high and 500 meters wide. At higher frequencies (100 MHz to 1 GHz (wavelengths of 3 meters to 30 cm)) very large parabolic or spherical reflectors used as the large ball "Dish" in Arecibo, Puerto Rico. For frequencies of (1 GHz to 10 GHz (wavelength of 30 cm to 30 mm)) medium to large parabolic reflectors used 5 to 90 meters in diameter.
These reflectors are fully articulated and can observe any object simply by pointing the reflector. For frequencies above 10 GHz (wavelengths of 30 mm to .3 mm) high precision necessary parabolic reflectors are typically 3 to 20 meters in diameter. The reflectors are more like mirrors and are thermally stable and supported by complex structures, as the surface curvature is held to demanding standards. The surface of these tolerances reflectors are held to plus or minus one hundredth of a millimeter radio telescopes in the millimeter to Sub-millimeter wavelength range. Each type of instrument opens a new set of "Colors" for the astronomers can the universe.
Optical telescopes and gives these clear images because the wavelength of visible light is so small in relation to the diameter of the focus device (mirror or lens). Radio waves with wavelengths of enormous comparison: Do not focus on the clean "images" rather they tend to deal with each other, since the focus device (reflector) is tiny compared to the wavelength. For the construction of a 10 mm wavelength radio telescope with imaging capabilities of a small 4-inch optical telescope will have a reflector, about 2 km (over 6000 meters) in diameter, clearly this enormous size is impractical. It may at first sight that radio astronomy would be doomed to low detail rather boring observations and data collection tasks. The fact that light and radio waves tend to each other is a technique known as interferometry. Simply put, this allows two or more antennas brought to justice far apart or in arrays (such as the VLA "Very Large Array in New Mexico) to function as if they were a large antenna (Aperture Synthesis). The interference between the signals from each of the receiving antennas, if timing corrections are introduced, allows for image reconstruction with Fourier transformations. We can look at the resolution of a 2 km antenna, by using multiple antennas 2 km apart and correlation of data. With this technique, it is possible to obtain milliarcsecond resolution. A milliarcsecond is about the equivalent of seeing one quarter in New York from Los Angeles!
With the advent of DSP (Digital Signal Processing), faster and smaller computers, and the introduction of super implementation of amplifiers radio astronomy has made progress to a fraction neck pace. New arrays of antennas are currently being developed and built. Some contain more than a thousand individual antennas all in harmony, what resolutions, the rival optical telescopes. Other arrays cover a hectare and a process extends over a square kilometre as "Phased Array type imaging capabilities never seen before. The future of radio astronomy looks brighter than ever before.
The difference is that while optical telescopes present images that are familiar in composition (ie the images on frequencies that we can see directly). Radio telescopes to observe the cosmos much lower frequencies. Most of us have seen the spectacular images acquired by the Hubble Space Telescope. To be sure these images not only give us an insight into the wonders of the universe, but move us in spirit by a sense of awe. Unfortunately, the primary sensory cells input device for us humans (eyes) is very limited "bandwidth" (the range of electromagnetic frequencies, or "colors" to which it is sensitive), and although the images move us, they do not give up their secrets easily . As a result, much of what happens in the universe is hidden from our view.
To put it simply, every color is a different frequency, and most of the color, with the range of the cosmos is painted is invisible to our eyes. It only makes sense, our sensitivity, the instrumentation, on the other frequencies of the electromagnetic spectrum. The radio telescope is one of those instruments. It allows us to monitor and the image of the universe at frequencies below our visual capabilities, which shows much of what is going on in the universe. Because certain frequencies pass easily through annoying dust and gas clouds, we can now study until now blocked objects from our point of view. Also, because certain gases, molecules and materials in the universe either emit or absorb light to radio frequencies, these structures can be viewed by the radio telescope. This feature not only allows the viewer to the image of these objects, but also allows the observers to collect much more information such as composition, speed, temperature and mass.
The range of frequencies, the spectrum is immense, so that the diversity and the types of instruments that make up radio telescopes is diverse in terms of design, size and configuration. Lower frequency (10 MHz - 100 MHz (wavelengths of 30 meters to 3 meters)) instruments are usually arrays of antennas similar to "TV antennas or are stationary reflectors of gigantic proportions with moveable nodes some are over 30 Meters high and 500 meters wide. At higher frequencies (100 MHz to 1 GHz (wavelengths of 3 meters to 30 cm)) very large parabolic or spherical reflectors used as the large ball "Dish" in Arecibo, Puerto Rico. For frequencies of (1 GHz to 10 GHz (wavelength of 30 cm to 30 mm)) medium to large parabolic reflectors used 5 to 90 meters in diameter.
These reflectors are fully articulated and can observe any object simply by pointing the reflector. For frequencies above 10 GHz (wavelengths of 30 mm to .3 mm) high precision necessary parabolic reflectors are typically 3 to 20 meters in diameter. The reflectors are more like mirrors and are thermally stable and supported by complex structures, as the surface curvature is held to demanding standards. The surface of these tolerances reflectors are held to plus or minus one hundredth of a millimeter radio telescopes in the millimeter to Sub-millimeter wavelength range. Each type of instrument opens a new set of "Colors" for the astronomers can the universe.
Optical telescopes and gives these clear images because the wavelength of visible light is so small in relation to the diameter of the focus device (mirror or lens). Radio waves with wavelengths of enormous comparison: Do not focus on the clean "images" rather they tend to deal with each other, since the focus device (reflector) is tiny compared to the wavelength. For the construction of a 10 mm wavelength radio telescope with imaging capabilities of a small 4-inch optical telescope will have a reflector, about 2 km (over 6000 meters) in diameter, clearly this enormous size is impractical. It may at first sight that radio astronomy would be doomed to low detail rather boring observations and data collection tasks. The fact that light and radio waves tend to each other is a technique known as interferometry. Simply put, this allows two or more antennas brought to justice far apart or in arrays (such as the VLA "Very Large Array in New Mexico) to function as if they were a large antenna (Aperture Synthesis). The interference between the signals from each of the receiving antennas, if timing corrections are introduced, allows for image reconstruction with Fourier transformations. We can look at the resolution of a 2 km antenna, by using multiple antennas 2 km apart and correlation of data. With this technique, it is possible to obtain milliarcsecond resolution. A milliarcsecond is about the equivalent of seeing one quarter in New York from Los Angeles!
With the advent of DSP (Digital Signal Processing), faster and smaller computers, and the introduction of super implementation of amplifiers radio astronomy has made progress to a fraction neck pace. New arrays of antennas are currently being developed and built. Some contain more than a thousand individual antennas all in harmony, what resolutions, the rival optical telescopes. Other arrays cover a hectare and a process extends over a square kilometre as "Phased Array type imaging capabilities never seen before. The future of radio astronomy looks brighter than ever before.
Minggu, 22 Juni 2008
Constellations - Canis Major
Big Dog is located southeast of Orion. A simple way to the constellation, the three stars that make up Orion belt and follow the stars in a westerly direction south until the next bright star. This is Sirius in Canis Major, its brightest star in the constellation ..South of Sirius, the open cluster M41 can be found. Like all open clusters, it contains a few hundred young stars and has no special form.
Together, the stars are just bright enough to see with the naked eye in a clear night without moon. With binoculars it appears as a faint smudge and in a telescope, the cluster is easily seen, about as much as the sky full moon does.
Since the cluster appears low in the sky from northern latitudes light pollution reduced the grandeur of these clusters but its still worth a look.
Sirius also has a companion star, Sirius B. known as Sirius B was the first "white dwarf" to be discovered.
Constellations - Cassiopeia
Cassiopeia is shaped by its W-shape in the sky, with stars magnitude 2 to 3.5 marking each turn in the Ursa Major W. How Cassiopeia is circumpolar and can be year-round from northern latitudes.Cassiopeia lies in the Milky Way, so many objects such as nebulae (clouds of gas and dust) and star clusters. Cassiopeia scanning with binoculars will show many of them not, however, the fog. The use of a telescope is still open.
The open cluster M103 is relatively easy to find as the double stars, try it with the localization of M52 with the Star-hopping technology. The items listed below are reflected in a 6 "telescope but some are quite small or sparsely populated as in the case of the M103.
Constellations - Ursa Major
Ursa Major, the Big Bear, is one of the best-known constellations. For those of us in northern latitudes, it may be the whole year as the constellation is circumpolar.The star in the middle of the bid Dipper handle is a Double Star, provides them with the naked eye, when the sky is clear and your vision is good. The brighter of the two stars is known as Mizar, and the weaker is Alcor.
In a telescope, Mizar turns out to be twice as we have a three-star system. All the major stars below exception duhbe Alkaid and are part of a cluster moving when you have to wait many thousands of years should be noted shift in position!
Constellations - Pegasus
Pegasus is marked by "The big square of Pegasus, four stars in the horse, the body that form a square whose sides are each over 10 ° degrees (the width of a fist, held up into the sky).You can find the Square of Pegasus, the line pointer from the car by the Great Polaris, and then twice so far in Polaris' other side. One of the stars (Alpheratz) is now actually on the border in the constellation Andromeda. The other three stars are in Pegasus. All are between 2nd and 3 Magnitude. There are no brighter stars on the court.
Pegasus is the home of some weak galaxies and globular clusters (M15). M15 is easy to see in binoculars although no detail too. A telescope shows a small detail at the edges on a night with good visibility.
You must be pretty experienced to monitor variables to spot the difference that Scheat displays different brightness of only half a magnitude! Good hunting.
Sabtu, 21 Juni 2008
Constellations - Cygnus
Cygnus lies in the Milky Way. His brightest stars mark the Northern Cross. Cygnus, with the bright star Deneb in the swan's tail, appears high in the sky summer. The three bright stars Deneb, Vega (in the constellation Lyra) and Altair (in the constellation of Aquila) mark the summer triangle. Altair is about 40 degrees of Deneb and Vega. Albireo, the bright star at the head of Cygnus is an excellent example of a telescope-Double Star. Even with binoculars, you can see that it consists of two stars of different colors, is a very orange the other bluish white. You must look at them.As Cygnus lies in the Milky Way is full of variable stars (stars, the brightness varies over a certain period) and the number of novae in the boundaries of this constellation - the last was in 1976.
The North American Nebula lies within Cygnus, it is very dark, but reportedly easy to photograph. The fog needs a telescope aperture greater than 6 ".
Star Profile: Fomalhaut
Here is a difficult question for astronomers everywhere: What is 17 brightest star in the sky?
The answer (if you do not guess it from the title of the article!) Fomalhaut is also known, rather curious, as the "First Frog" or alternatively "The Lonely One". It is in the constellation of the southern fish (Pisces Austrinus), which actually looks like a fish stylistic lying on his back drinking in the waters of knowledge of water man.
Fomalhaut is a bluish white star, younger than our Sun and lies about 25 light years away. It is surrounded by a warped disk of icy dust particles similar to that around Vega, Beta Pictoris and Denebola.
Fomalhaut may hold secrets of a planetary system, its dusty ring is similar to the hard disk through the solar system Edgeworth-Kuiper belt.
So where is this star to his name, and how do you speak? Now, "FUM-al-HUT" in Arabic means fish's mouth, and I said it is pronounced "Foma-low" in English. This makes it easier for me to remember because Fomalhaut is low in the southern autumn sky.
It is a suspicion of variable stars and was categorized under many names: TYC6977: 1267:1 HR8728, Hip113368, HD216956, SAO191524, and LTT9292, to name just a few.
Mr Thomas Jefferson Jackson Lake reported a companion red-orange dwarf TW Piscis (CG31978, SAO214197, TYC7505: 100:1), 1897.
Another dwarf star known as K5-LTT8273 can be a visual companion. This particular star is originally conceived as a member of a now scattered clusters including Fomalhaut, Vega and Castor. Fomalhaut the future can be developed into a white dwarf in a billion years. (Do not wait!)
Did Fomalhaut's dusty disk coalesced into planets around the star? Theories point to this possibility. Rumour has it that our solar system may have looked like the dusty Fomalhaut system four billion years. I think you enjoy watching this star - it's more than just a small glimmer in the southern sky.
The answer (if you do not guess it from the title of the article!) Fomalhaut is also known, rather curious, as the "First Frog" or alternatively "The Lonely One". It is in the constellation of the southern fish (Pisces Austrinus), which actually looks like a fish stylistic lying on his back drinking in the waters of knowledge of water man.
Fomalhaut is a bluish white star, younger than our Sun and lies about 25 light years away. It is surrounded by a warped disk of icy dust particles similar to that around Vega, Beta Pictoris and Denebola.
Fomalhaut may hold secrets of a planetary system, its dusty ring is similar to the hard disk through the solar system Edgeworth-Kuiper belt.
So where is this star to his name, and how do you speak? Now, "FUM-al-HUT" in Arabic means fish's mouth, and I said it is pronounced "Foma-low" in English. This makes it easier for me to remember because Fomalhaut is low in the southern autumn sky.
It is a suspicion of variable stars and was categorized under many names: TYC6977: 1267:1 HR8728, Hip113368, HD216956, SAO191524, and LTT9292, to name just a few.
Mr Thomas Jefferson Jackson Lake reported a companion red-orange dwarf TW Piscis (CG31978, SAO214197, TYC7505: 100:1), 1897.
Another dwarf star known as K5-LTT8273 can be a visual companion. This particular star is originally conceived as a member of a now scattered clusters including Fomalhaut, Vega and Castor. Fomalhaut the future can be developed into a white dwarf in a billion years. (Do not wait!)
Did Fomalhaut's dusty disk coalesced into planets around the star? Theories point to this possibility. Rumour has it that our solar system may have looked like the dusty Fomalhaut system four billion years. I think you enjoy watching this star - it's more than just a small glimmer in the southern sky.
The End Of The Universe - Big Crunch Or Big Bang?
Scientist working on the Sudbury Neutrino Observatory (SNO) in Ontario, Canada have finally revealed the fate of the universe ...
They have managed to calculate the mass of the elusive neutrino particle and have found that the sum of the masses of the colossal amount of neutrinos in our universe is not enough to end a universal expansion. The universe is destined to expand forever, until there was a cold, dark place, free from all signs of life.
What is a neutrino anyway?
Technically a neutrino is a lepton with zero-tax, half of spin and a very small mass, which only interacts with other particles by weak interaction. Its existence was first postulated by Wolfgang Pauli to the lack of energy in the beta decay. It is suspected that neutrinos make up a large part of the dark matter in our universe. Neutrinos come in three types: electron, muon and tau.
The physicist working on the project was an attempt to explain the problem of missing solar neutrinos. The nuclear reaction heats the sun emit a large amount of electron neutrinos, but experiments find that only a fraction of the expected amount of electron neutrinos reaching Earth.
The experiments in Sudbury shown that neutrinos can oscillate between the various species to the discrepancy in the amount of electron neutrinos. This interesting discovery is far-reaching, that means that the direct evidence for solar neutrino transformation also points out that neutrinos have mass, and by combining this with information previously provided, it is possible to set a ceiling for the sum of the known neutrino masses. According to Scott Tremaine, a professor of astrophysical sciences at Princeton University, "This is the last clue, we must determine the fate of the universe".
Missing Mass
In order for the universe to stop expansion and eventually contract to a "big crunch", the mass of the universe must have a certain value. The stars and galaxies in the universe detectable by our telescopes and instruments, only a small fraction of this total mass, a claim clearly supported by indirect evidence such as the rotation of galaxies.
Therefore, neutrinos were thought to a large part of the dark matter in the universe. But with an upper limit for its mass, the total mass of the universe can not reach the critical level, so that our universe will certainly expand to infinity, with all of its remaining consequences.
Follow
If the "big crunch" model is discarded, the universe is predicted to expand to a diffuse, dark nothing during the successive degenerate black hole and dark periods. Planets of stars are resolved, which in turn evaporate of galaxies. The proton decay, all the stars run out of fuel and are engulfed by black holes, which radiate all of their masses and leave the universe is a huge, cold, sterile place.
Update to the article:
The Ontario research is no last word. A new force called "dark energy" is known to push clusters of galaxies apart and their composition is unknown. This could also be an impact on the fate of the universe. In addition, astrophysics constants like the fine structure constant (alpha) slowly over time. At some point, like a constant or an α-particle mass disintegration past May at a critical point and universal matter would disintegrate. Whatever happens will not happen during our lives or our children, and hence there is no reason for concern - although scientists can a black hole capable of swallowing the earth.
They have managed to calculate the mass of the elusive neutrino particle and have found that the sum of the masses of the colossal amount of neutrinos in our universe is not enough to end a universal expansion. The universe is destined to expand forever, until there was a cold, dark place, free from all signs of life.
What is a neutrino anyway?
Technically a neutrino is a lepton with zero-tax, half of spin and a very small mass, which only interacts with other particles by weak interaction. Its existence was first postulated by Wolfgang Pauli to the lack of energy in the beta decay. It is suspected that neutrinos make up a large part of the dark matter in our universe. Neutrinos come in three types: electron, muon and tau.
The physicist working on the project was an attempt to explain the problem of missing solar neutrinos. The nuclear reaction heats the sun emit a large amount of electron neutrinos, but experiments find that only a fraction of the expected amount of electron neutrinos reaching Earth.
The experiments in Sudbury shown that neutrinos can oscillate between the various species to the discrepancy in the amount of electron neutrinos. This interesting discovery is far-reaching, that means that the direct evidence for solar neutrino transformation also points out that neutrinos have mass, and by combining this with information previously provided, it is possible to set a ceiling for the sum of the known neutrino masses. According to Scott Tremaine, a professor of astrophysical sciences at Princeton University, "This is the last clue, we must determine the fate of the universe".
Missing Mass
In order for the universe to stop expansion and eventually contract to a "big crunch", the mass of the universe must have a certain value. The stars and galaxies in the universe detectable by our telescopes and instruments, only a small fraction of this total mass, a claim clearly supported by indirect evidence such as the rotation of galaxies.
Therefore, neutrinos were thought to a large part of the dark matter in the universe. But with an upper limit for its mass, the total mass of the universe can not reach the critical level, so that our universe will certainly expand to infinity, with all of its remaining consequences.
Follow
If the "big crunch" model is discarded, the universe is predicted to expand to a diffuse, dark nothing during the successive degenerate black hole and dark periods. Planets of stars are resolved, which in turn evaporate of galaxies. The proton decay, all the stars run out of fuel and are engulfed by black holes, which radiate all of their masses and leave the universe is a huge, cold, sterile place.
Update to the article:
The Ontario research is no last word. A new force called "dark energy" is known to push clusters of galaxies apart and their composition is unknown. This could also be an impact on the fate of the universe. In addition, astrophysics constants like the fine structure constant (alpha) slowly over time. At some point, like a constant or an α-particle mass disintegration past May at a critical point and universal matter would disintegrate. Whatever happens will not happen during our lives or our children, and hence there is no reason for concern - although scientists can a black hole capable of swallowing the earth.
Jumat, 20 Juni 2008
Stellar Evolution, The Lives of Stars
Where stars are born?
Astronomers believe that molecular clouds, dense clouds of gas lies in the spiral arms of galaxies are the birthplace of stars. Dense regions in the clouds collapse and form 'protostars, "said a star begins his life as a large mass of relatively cool gas. The contraction of the gas and the subsequent rise in temperature continues until the internal temperature of the star reached a value of approximately 1000000 ° C (about 1800000 ° F).
At this point a nuclear reaction takes place in which the nuclei of hydrogen atoms combine with heavy hydrogen deuterons (cores of so-called heavy hydrogen atoms) form the core of the inert gas helium. The latter reaction liberated large quantities of nuclear energy, and the further contraction of the star is stopped. Once the star has begun nuclear fusion, there will be a "main sequence" star.
Main sequence stars
Main sequence stars are stars like our sun, burning hydrogen into helium in their veins. For a certain chemical composition and age of stellar, stars' luminosity, the total energy radiated by the star per unit of time depends only on its mass. Stars, ten times more massive than the sun are more than a thousand times more luminous than the sun. But we should not be embarrassed by the sun low luminosity: It is ten times brighter than a star half its mass. The more massive a main sequence star, the brighter and blue it is.
For example, Sirius - the dog star is located on the lower left corner of the constellation Orion, is more massive than the sun and blue is palpable. On the other hand, Alpha Centauri, our nearest neighbour, is less massive than the sun, and is therefore redder and less light intensity.
Since stars have a limited supply of hydrogen in their cores, they have a limited life span as main sequence stars. Life is proportional to the FM / L, where f is the fraction of the total mass of the star, M, available for nuclear fusion in the core areas and L is the average brightness of the star during his lifetime main sequence. Due to the heavy dependence on the luminosity of mass stellar life depends sensitively on earth. Thus, it is fortunate that our sun is nothing more than massive, it is high since stars quickly exhaust their core competencies hydrogen supply.
Once a star exhausts its core hydrogen supply, the star is redder, more and more lights Strength: It is a red giant star. This relationship between mass and life allows astronomers to a lower limit for the age of the universe.
Death of a "normal" Star
After a low mass stars like the sun exhausted the supply of hydrogen in its core, there is no longer a heat source to support the core against the force of gravity. The core of the star collapse under the force of gravity drag until it reaches a high enough density to begin converting helium to carbon. Meanwhile, the stars' outer envelope and expands the star develops into a red giant. When the sun into a red giant, the atmosphere is the shape the earth and our planet will be consumed in a fiery death. The sun will ultimately lead to a red supergiant, as they exhausted the helium in its core. At this stage, there will be an extension outer envelope in the direction of Jupiter. During this short period of its existence, the last just a few tens of thousands of years, the sun is losing mass in a powerful winds.
Eventually, the sun loses all the mass in his bag and left behind a hot core of carbon embedded in a fog of gas expelled. Radiation from the hot core is ionise the fog creates a striking "planetary nebula", like the fog to the remains of other stars. The carbon-core will cool and finally to a white dwarf, the dense remnant dim once a bright star. The final fate of low-mass dwarfs is not known, except that they cease to radiate noticeable. Probably they will be incinerated ash, or black dwarfs.
The death of a massive star
Massive stars burn brighter and lost more than most dramatically. When a star ten times more massive then To exhaust the helium in the core of nuclear fusion cycle. The carbon-core treaties, and reached a high enough temperature to burn carbon to oxygen, neon, silicon, sulfur and finally to iron.
Iron is the most stable form of the nuclear issue and there is no energy to gain by participating in any heavier element. Without any heat source to compensate for gravity, the iron core collapses until it reaches the nuclear densities. This high density core resists further cause of the collapse in falling matter to "bounce" from the core.
This sudden bounce core (including the release of energetic neutrinos from the core) creates a supernova explosion. For a brilliant month, a single star burns brighter than an entire galaxy of a billion stars. Supernova explosions inject carbon, oxygen, silicon and other heavy elements up to iron in the interstellar space. They are also the place where most of the elements heavier than iron are produced.
Future generations of stars formed from this major element enriched gas is therefore start life with a richer supply of heavier elements than the previous generations of stars. Without supernova, the fiery death of massive stars, there would be no carbon, oxygen or other elements that make life possible.
The fate of the hot neutron star core depends on the mass of the progenitor star. If the progenitor mass is about ten times the mass of the sun, neutron star core will cool for a neutron star. Neutron stars are potentially detectable as "pulsars", powerful beacons of radio emission. There is a limit for the size of neutron stars, but beyond which such stars are gravitationally bound to keep contracting until it is a black hole from which light rays can not escape.
If the progenitor mass is greater, then the resulting core is so difficult that not even the nuclear forces can resist the pull of gravity and the core collapses to a black hole.
Astronomers believe that molecular clouds, dense clouds of gas lies in the spiral arms of galaxies are the birthplace of stars. Dense regions in the clouds collapse and form 'protostars, "said a star begins his life as a large mass of relatively cool gas. The contraction of the gas and the subsequent rise in temperature continues until the internal temperature of the star reached a value of approximately 1000000 ° C (about 1800000 ° F).
At this point a nuclear reaction takes place in which the nuclei of hydrogen atoms combine with heavy hydrogen deuterons (cores of so-called heavy hydrogen atoms) form the core of the inert gas helium. The latter reaction liberated large quantities of nuclear energy, and the further contraction of the star is stopped. Once the star has begun nuclear fusion, there will be a "main sequence" star.
Main sequence stars
Main sequence stars are stars like our sun, burning hydrogen into helium in their veins. For a certain chemical composition and age of stellar, stars' luminosity, the total energy radiated by the star per unit of time depends only on its mass. Stars, ten times more massive than the sun are more than a thousand times more luminous than the sun. But we should not be embarrassed by the sun low luminosity: It is ten times brighter than a star half its mass. The more massive a main sequence star, the brighter and blue it is.
For example, Sirius - the dog star is located on the lower left corner of the constellation Orion, is more massive than the sun and blue is palpable. On the other hand, Alpha Centauri, our nearest neighbour, is less massive than the sun, and is therefore redder and less light intensity.
Since stars have a limited supply of hydrogen in their cores, they have a limited life span as main sequence stars. Life is proportional to the FM / L, where f is the fraction of the total mass of the star, M, available for nuclear fusion in the core areas and L is the average brightness of the star during his lifetime main sequence. Due to the heavy dependence on the luminosity of mass stellar life depends sensitively on earth. Thus, it is fortunate that our sun is nothing more than massive, it is high since stars quickly exhaust their core competencies hydrogen supply.
Once a star exhausts its core hydrogen supply, the star is redder, more and more lights Strength: It is a red giant star. This relationship between mass and life allows astronomers to a lower limit for the age of the universe.
Death of a "normal" Star
After a low mass stars like the sun exhausted the supply of hydrogen in its core, there is no longer a heat source to support the core against the force of gravity. The core of the star collapse under the force of gravity drag until it reaches a high enough density to begin converting helium to carbon. Meanwhile, the stars' outer envelope and expands the star develops into a red giant. When the sun into a red giant, the atmosphere is the shape the earth and our planet will be consumed in a fiery death. The sun will ultimately lead to a red supergiant, as they exhausted the helium in its core. At this stage, there will be an extension outer envelope in the direction of Jupiter. During this short period of its existence, the last just a few tens of thousands of years, the sun is losing mass in a powerful winds.
Eventually, the sun loses all the mass in his bag and left behind a hot core of carbon embedded in a fog of gas expelled. Radiation from the hot core is ionise the fog creates a striking "planetary nebula", like the fog to the remains of other stars. The carbon-core will cool and finally to a white dwarf, the dense remnant dim once a bright star. The final fate of low-mass dwarfs is not known, except that they cease to radiate noticeable. Probably they will be incinerated ash, or black dwarfs.
The death of a massive star
Massive stars burn brighter and lost more than most dramatically. When a star ten times more massive then To exhaust the helium in the core of nuclear fusion cycle. The carbon-core treaties, and reached a high enough temperature to burn carbon to oxygen, neon, silicon, sulfur and finally to iron.
Iron is the most stable form of the nuclear issue and there is no energy to gain by participating in any heavier element. Without any heat source to compensate for gravity, the iron core collapses until it reaches the nuclear densities. This high density core resists further cause of the collapse in falling matter to "bounce" from the core.
This sudden bounce core (including the release of energetic neutrinos from the core) creates a supernova explosion. For a brilliant month, a single star burns brighter than an entire galaxy of a billion stars. Supernova explosions inject carbon, oxygen, silicon and other heavy elements up to iron in the interstellar space. They are also the place where most of the elements heavier than iron are produced.
Future generations of stars formed from this major element enriched gas is therefore start life with a richer supply of heavier elements than the previous generations of stars. Without supernova, the fiery death of massive stars, there would be no carbon, oxygen or other elements that make life possible.
The fate of the hot neutron star core depends on the mass of the progenitor star. If the progenitor mass is about ten times the mass of the sun, neutron star core will cool for a neutron star. Neutron stars are potentially detectable as "pulsars", powerful beacons of radio emission. There is a limit for the size of neutron stars, but beyond which such stars are gravitationally bound to keep contracting until it is a black hole from which light rays can not escape.
If the progenitor mass is greater, then the resulting core is so difficult that not even the nuclear forces can resist the pull of gravity and the core collapses to a black hole.
X-Ray Background, Everpresent Noise
X-ray background Mystery Resolved
In astronomy, high energy prices, each photon counts, and the background events were as big as a secret of the objects in the foreground. In the X-ray astronomy in particular, the unexplained "noise" takes the form of a diffuse and apparently quite significant background, where the detector points.
A component flows evenly from all directions in the sky, while another strongly correlated with the disk of the Milky Way, so that we will probably see two different phenomena and have at least two puzzles. Recently, astronomers using a new instrument in the form of the Chandra X-Ray Observatory, which has in the investigation of the sharpest x-ray vision ever.
The first secret is relatively close at hand, namely the magnitude of "only" tens of thousands of light years away within our own Milky Way. Astronomers see that the thin disk of our galaxy bright lights in high energy or "hard", x-rays. Until now, no x-ray telescope could, if these emissions came from many individual stellar sources such as neutron stars or if it is through the room.
An international team led by Dr. Ken Ebisawa from NASA's Goddard Space Flight Center to Chandra for a long look at a region of the galactic plane in the constellation Scutum. What they see in the highest resolution x-ray image ever taken is that 90% of the total emission is really something diffuse and by the level of the galaxy. That something most likely to hot ionized gas or plasma, when "hot" puts it mildly to radiate in the x-ray band, the plasma would probably have dozens of millions of degrees.
But that only leads to another series of questions: Where did the plasma came from and why they stay on the narrow disk? The hot gas has more than enough energy to escape the gravitational pull of the galaxy, something needs to be limited. Not knowing where it comes from or what does it mean that astronomers are not on one of the most energetic processes in our own neighborhood. But they are never short of theories. That the ionized gas may be a big hint. Dr. Ebisawa pointed out that ionized gas, where the outer electrons have been stripped off the atoms from a net positive charge could then only through a magnetic field.
In addition, if Chandra shows the emission as a diffuse, it is by no means uniform. It is clumpy, and some patches of higher intensity are suspiciously close supernova remnants suspected. These powerful explosions could well be the source of plasma, but none of the many models of supernova pattern is still itself from the pack by providing a testable statement. The new data have only one observational uncertainty, so that the real physics behind to be discovered.
The unaccounted for 10% of their data seems to be far short of gas in the galactic plane, and it is part of the second secret, component, which uniformly in all directions. In contrast to the cosmic microwave background (in brief, the fugitive remained heat from the "Big Bang"), these x-ray background is not to explain every theory about the origins of the universe. Nor can it be explained by the adoption of a uniform distribution of objects similar to what we have already solved in the area, there are not enough sources to explain the amount of radiation we see in the distance.
Also, two independent teams of astronomers recently Chandra pointed to a few apparently empty piece of the sky for low exposures of 500000 and one million seconds. Now known as the Chandra Deep Fields North and South, everyone is in reality a window from our own galaxy with a view to the more distant universe.
In this case, however, the issue turns out to be due to the many different sources of X-rays, which have been identified as distant quasars by signing energy spectra. Quasars are the very bright cores of galaxies some of the spew out large quantities of high-energy radiation, so much radiation, it can only because of a black hole many millions of times the mass of the sun. The average distance from these sources means that they represent the universe as it was when much younger, just a few billion years old from its current estimated age of 15 billion years.
This result is surprising consequences for the astronomers to understand the evolution of galaxies. He says that it is much more quasars seen in the past than now, increasing the big question: What happens to them? The implication is that quasars may be a stage of galaxy evolution, even by the apparently normal galaxies like ours in May passed.
These galaxies have their headquarters in the port of supermassive black holes, only now the black holes are quiet, perhaps because after a few billion years gobbling up everything in reach, there are no more material near enough to feed them. The Chandra data significantly strengthens this evolutionary view that the most normal galaxies can essentially "fossil quasars.
But the solution to the mystery of observations has further questions for astronomers. Among them is the question of what came first, the galaxy or black hole? Was the black hole born in the dense center of a galaxy existing, or has the galaxy form around a "seed capital" black hole? If the latter, where did the seed black holes come from? Although uncertainty has been observational rest of the x-ray background, astronomers are still a lot to learn from the "noise".
In astronomy, high energy prices, each photon counts, and the background events were as big as a secret of the objects in the foreground. In the X-ray astronomy in particular, the unexplained "noise" takes the form of a diffuse and apparently quite significant background, where the detector points.
A component flows evenly from all directions in the sky, while another strongly correlated with the disk of the Milky Way, so that we will probably see two different phenomena and have at least two puzzles. Recently, astronomers using a new instrument in the form of the Chandra X-Ray Observatory, which has in the investigation of the sharpest x-ray vision ever.
The first secret is relatively close at hand, namely the magnitude of "only" tens of thousands of light years away within our own Milky Way. Astronomers see that the thin disk of our galaxy bright lights in high energy or "hard", x-rays. Until now, no x-ray telescope could, if these emissions came from many individual stellar sources such as neutron stars or if it is through the room.
An international team led by Dr. Ken Ebisawa from NASA's Goddard Space Flight Center to Chandra for a long look at a region of the galactic plane in the constellation Scutum. What they see in the highest resolution x-ray image ever taken is that 90% of the total emission is really something diffuse and by the level of the galaxy. That something most likely to hot ionized gas or plasma, when "hot" puts it mildly to radiate in the x-ray band, the plasma would probably have dozens of millions of degrees.
But that only leads to another series of questions: Where did the plasma came from and why they stay on the narrow disk? The hot gas has more than enough energy to escape the gravitational pull of the galaxy, something needs to be limited. Not knowing where it comes from or what does it mean that astronomers are not on one of the most energetic processes in our own neighborhood. But they are never short of theories. That the ionized gas may be a big hint. Dr. Ebisawa pointed out that ionized gas, where the outer electrons have been stripped off the atoms from a net positive charge could then only through a magnetic field.
In addition, if Chandra shows the emission as a diffuse, it is by no means uniform. It is clumpy, and some patches of higher intensity are suspiciously close supernova remnants suspected. These powerful explosions could well be the source of plasma, but none of the many models of supernova pattern is still itself from the pack by providing a testable statement. The new data have only one observational uncertainty, so that the real physics behind to be discovered.
The unaccounted for 10% of their data seems to be far short of gas in the galactic plane, and it is part of the second secret, component, which uniformly in all directions. In contrast to the cosmic microwave background (in brief, the fugitive remained heat from the "Big Bang"), these x-ray background is not to explain every theory about the origins of the universe. Nor can it be explained by the adoption of a uniform distribution of objects similar to what we have already solved in the area, there are not enough sources to explain the amount of radiation we see in the distance.
Also, two independent teams of astronomers recently Chandra pointed to a few apparently empty piece of the sky for low exposures of 500000 and one million seconds. Now known as the Chandra Deep Fields North and South, everyone is in reality a window from our own galaxy with a view to the more distant universe.
In this case, however, the issue turns out to be due to the many different sources of X-rays, which have been identified as distant quasars by signing energy spectra. Quasars are the very bright cores of galaxies some of the spew out large quantities of high-energy radiation, so much radiation, it can only because of a black hole many millions of times the mass of the sun. The average distance from these sources means that they represent the universe as it was when much younger, just a few billion years old from its current estimated age of 15 billion years.
This result is surprising consequences for the astronomers to understand the evolution of galaxies. He says that it is much more quasars seen in the past than now, increasing the big question: What happens to them? The implication is that quasars may be a stage of galaxy evolution, even by the apparently normal galaxies like ours in May passed.
These galaxies have their headquarters in the port of supermassive black holes, only now the black holes are quiet, perhaps because after a few billion years gobbling up everything in reach, there are no more material near enough to feed them. The Chandra data significantly strengthens this evolutionary view that the most normal galaxies can essentially "fossil quasars.
But the solution to the mystery of observations has further questions for astronomers. Among them is the question of what came first, the galaxy or black hole? Was the black hole born in the dense center of a galaxy existing, or has the galaxy form around a "seed capital" black hole? If the latter, where did the seed black holes come from? Although uncertainty has been observational rest of the x-ray background, astronomers are still a lot to learn from the "noise".
Big Bang, Beginning of The Universe
The universe as we see today is growing from a generally accepted theory event in the space-time called "Big Bang", which is about 13.7 billion years old.
We have found that clusters of galaxies, including our own, was brought back from each other. A common analogy for our expansion of the universe is a spotted balloon is blown. As the balloon expands, so that even the distance between the spots. This increased distance is obvious and clearly the case when the many clusters of galaxies in our universe.
We observe the galaxies recede from us and believe us as stationary, but this is only our relative view of the universe. For example, a galaxy of us back to a set of 'X' km / sec would our galaxy away from saying that at the same speed. Some galaxies do not recede from each other because their gravity keeps them together. These are the groups called galactic clusters.
If another galaxy, the speed increases in relation to its distance from our own Milky Way, the galaxy will inevitably other, "lightspeed" and in fact no longer be observed. This distance, the limit of the observable universe, is not the end of the universe itself, but it is assumed that somewhere in the region from 15 to 20 billion light years away, a distance we have yet to penetrate.
In 1929 Edwin Hubble, an American astronomer, discovered that all the galaxies around us were, because light analyses of each galaxy was red-shifted (the absorption lines were shifted to the red side of the spectrum, an effect known as the Doppler effect indicating that the lights were off our galaxy). Edwin suspected that the further the galaxy, the faster its recession of the earth, this was known as the Hubble constant (Ho).
The equation for the Hubble constant (Ho = v / d) is simple in form, but very difficult to specify because the figures are largely inaccurate (v is a galaxy's radial velocity to the outside world, ie the movement of the galaxy from our Line - of-view and d galaxy is that the distance from the Earth). An accurate results based on the accuracy of the values for v, (d more difficult since the two reliable distance markers - such as variable stars and supernovae - must be found in galaxies to determine their distances).
Even today a precise figure for the Hubble constant may not be agreed. Two teams of researchers in the search for the Hubble constant have conflicting results. The first team - in connection with Allan Sandage of the Carnegie Institutions - has received a value of 57 km / sec / Mpc with type 1a supernovae. The second team - in connection with Wendy Freedman of the same institution - has a value of about 70 km / sec / Mpc Cepheids and with the Hubble Space Telescope.
The structure of the universe is not fully known. Are there any limits? Stephen Hawking believes that the universe is finite or infinite in size. One could Keep on Moving in one direction and finally at the end to the same place. As an analogy, if you went in a straight line to earth, would you finally back on the same point where you started.
We have found that clusters of galaxies, including our own, was brought back from each other. A common analogy for our expansion of the universe is a spotted balloon is blown. As the balloon expands, so that even the distance between the spots. This increased distance is obvious and clearly the case when the many clusters of galaxies in our universe.
We observe the galaxies recede from us and believe us as stationary, but this is only our relative view of the universe. For example, a galaxy of us back to a set of 'X' km / sec would our galaxy away from saying that at the same speed. Some galaxies do not recede from each other because their gravity keeps them together. These are the groups called galactic clusters.
If another galaxy, the speed increases in relation to its distance from our own Milky Way, the galaxy will inevitably other, "lightspeed" and in fact no longer be observed. This distance, the limit of the observable universe, is not the end of the universe itself, but it is assumed that somewhere in the region from 15 to 20 billion light years away, a distance we have yet to penetrate.
In 1929 Edwin Hubble, an American astronomer, discovered that all the galaxies around us were, because light analyses of each galaxy was red-shifted (the absorption lines were shifted to the red side of the spectrum, an effect known as the Doppler effect indicating that the lights were off our galaxy). Edwin suspected that the further the galaxy, the faster its recession of the earth, this was known as the Hubble constant (Ho).
The equation for the Hubble constant (Ho = v / d) is simple in form, but very difficult to specify because the figures are largely inaccurate (v is a galaxy's radial velocity to the outside world, ie the movement of the galaxy from our Line - of-view and d galaxy is that the distance from the Earth). An accurate results based on the accuracy of the values for v, (d more difficult since the two reliable distance markers - such as variable stars and supernovae - must be found in galaxies to determine their distances).
Even today a precise figure for the Hubble constant may not be agreed. Two teams of researchers in the search for the Hubble constant have conflicting results. The first team - in connection with Allan Sandage of the Carnegie Institutions - has received a value of 57 km / sec / Mpc with type 1a supernovae. The second team - in connection with Wendy Freedman of the same institution - has a value of about 70 km / sec / Mpc Cepheids and with the Hubble Space Telescope.
The structure of the universe is not fully known. Are there any limits? Stephen Hawking believes that the universe is finite or infinite in size. One could Keep on Moving in one direction and finally at the end to the same place. As an analogy, if you went in a straight line to earth, would you finally back on the same point where you started.
Dark Matter And Its Implications
Definition
Dark matter is non-luminous matter, which can not directly observe, from any form of electromagnetic radiation (light), but whose existence is suggested because of the effects of gravity on the rotation of galaxies and the presence of galaxy clusters.
The density of the universe
The universe as we understand it now with the "Big Bang" when it began a period of very rapid expansion. Astronomers and cosmologists alike have tried to find out whether the universe will continue to expand forever or recollapse in a "big crunch".
It all depends on the ratio between the actual density of the universe to its critical density. Cosmologists call this relationship with the Greek letter Omega. If Omega is larger than a focus will then cause the universe to recollapse if less than one it will expand forever, and if it is equal to one to extend deccelrating rate perpetually.
The critical density of the universe was drawn up more than 5 atoms per cubic metre, which is very little considering that much closer to a perfect vacuum as experimenters on earth will ever hope to achieve.
The actual density of the universe is not known, but if you only the visible material that you stayed with a density of 0.2 atoms per cubic metre. Many cosmologists believe that it is much more matter in the universe can be seen, than by our telecopes, and they have observations and theoretical proof for their beliefs, as I describe in the next few paragraphs.
Rotation of galaxies
Galaxies in the vicinity of the Milky Way appear to be rotating faster than might be expected on the basis of the amount of visible matter, seems to be in these galaxies. Based on their rates of rotation, many astronomers believe that up to 90 percent of matter in a typical galaxy is invisible.
Galaxy clusters
In the universe are stars in galaxies and the galaxies themselves are in clusters. Some astronomers argue that if some reasonable assumptions acceptable - and that the cluster galaxies are linked by gravity, and that the cluster formed billions of years - then it follows that more than 90 percent of the Matter in a particular cluster is made up of dark matter. Otherwise, the proponents argue that interpretation, cluster would not be enough mass to hold it together, and the galaxies would have apart from now.
What is dark matter?
Astronomers and cosmologists know that dark matter exists but do not know what it is, or how much it actually is.
There are many candidates for dark matter, including undetected brown dwarf stars, White Dwarf stars, black holes, or with a mass of neutrinos (Neutrino basic nuclear particles, the electrically neutral and the much smaller mass, if any, as an electron), or even exotic subatomic particles, such as weaklings were (weak Interacting Massive Particles) or macho (Massive Compact Halo Objects). Physicists are currently searching for such particles in underground laboratories (to avoid interference), and learn how to detect them.
This will then recollapse the universe?
Despite the fact that up to 90 percent of the mass of the universe may still be out of the dark matter that cosmologists do not think it would be enough to have the force of gravity halt the expansion and cause a recollapse. This thinking is partly due to observation of supernovae in 1997, suggesting that the expansion is still not speeding up and slowing down at all.
A longer duration universe will not do much, but for us as (it is presumed not known) in the very distant (as distant years 1030 - 1000000000000000000000000000000 years!) If the protons decay, all the stars run out of fuel and are engulfed by Black holes, which in turn radiate all their mass (as in the article on black holes), so that the universe is a large, cold, sterile and lifeless.
Dark matter is non-luminous matter, which can not directly observe, from any form of electromagnetic radiation (light), but whose existence is suggested because of the effects of gravity on the rotation of galaxies and the presence of galaxy clusters.
The density of the universe
The universe as we understand it now with the "Big Bang" when it began a period of very rapid expansion. Astronomers and cosmologists alike have tried to find out whether the universe will continue to expand forever or recollapse in a "big crunch".
It all depends on the ratio between the actual density of the universe to its critical density. Cosmologists call this relationship with the Greek letter Omega. If Omega is larger than a focus will then cause the universe to recollapse if less than one it will expand forever, and if it is equal to one to extend deccelrating rate perpetually.
The critical density of the universe was drawn up more than 5 atoms per cubic metre, which is very little considering that much closer to a perfect vacuum as experimenters on earth will ever hope to achieve.
The actual density of the universe is not known, but if you only the visible material that you stayed with a density of 0.2 atoms per cubic metre. Many cosmologists believe that it is much more matter in the universe can be seen, than by our telecopes, and they have observations and theoretical proof for their beliefs, as I describe in the next few paragraphs.
Rotation of galaxies
Galaxies in the vicinity of the Milky Way appear to be rotating faster than might be expected on the basis of the amount of visible matter, seems to be in these galaxies. Based on their rates of rotation, many astronomers believe that up to 90 percent of matter in a typical galaxy is invisible.
Galaxy clusters
In the universe are stars in galaxies and the galaxies themselves are in clusters. Some astronomers argue that if some reasonable assumptions acceptable - and that the cluster galaxies are linked by gravity, and that the cluster formed billions of years - then it follows that more than 90 percent of the Matter in a particular cluster is made up of dark matter. Otherwise, the proponents argue that interpretation, cluster would not be enough mass to hold it together, and the galaxies would have apart from now.
What is dark matter?
Astronomers and cosmologists know that dark matter exists but do not know what it is, or how much it actually is.
There are many candidates for dark matter, including undetected brown dwarf stars, White Dwarf stars, black holes, or with a mass of neutrinos (Neutrino basic nuclear particles, the electrically neutral and the much smaller mass, if any, as an electron), or even exotic subatomic particles, such as weaklings were (weak Interacting Massive Particles) or macho (Massive Compact Halo Objects). Physicists are currently searching for such particles in underground laboratories (to avoid interference), and learn how to detect them.
This will then recollapse the universe?
Despite the fact that up to 90 percent of the mass of the universe may still be out of the dark matter that cosmologists do not think it would be enough to have the force of gravity halt the expansion and cause a recollapse. This thinking is partly due to observation of supernovae in 1997, suggesting that the expansion is still not speeding up and slowing down at all.
A longer duration universe will not do much, but for us as (it is presumed not known) in the very distant (as distant years 1030 - 1000000000000000000000000000000 years!) If the protons decay, all the stars run out of fuel and are engulfed by Black holes, which in turn radiate all their mass (as in the article on black holes), so that the universe is a large, cold, sterile and lifeless.
Black Holes, Invisible Bodies of Intense Gravity
A black hole is an (almost invisible) body in space, most likely created by a collapsed star super red giant, which is so dense that neither matter nor light can escape its attraction.
Inside a star, there is a constant struggle between the pressure of active and passive gravity pressure from heat. If you were to throw an unopened can of soda in a fire, the drink would remove from the heat and explode. This is the same principle at work when a star is burning, its heat generated great pressure to the outside, but this constant explosion is by gravity, is just as strong, so that a star maintains its shape and size.
When a star is approaching the end of his life it slowly cools and the outside pressure is growing weaker and weaker as the temperature of the star drops. The passive pressure of the heat is almost over, the pressure from inside gravity and still depends on the size of the star. It is the theory that if a star is about ten times as large as our sun is approaching the end of his life, as it shrinks its own gravity pulls it slowly, but as soon as they are more and more dense the gravity is stronger.
The focus is so intense that not even light can escape. Have you ever seen a swirling water flow, then you have a pretty good idea what happened, like a black hole draws in. As things matter and light approach near a black hole slowly, they are in. If they do not tip, especially for the spatial anomaly then they are in a violent and unstable orbit around the black hole until the orbit decays and it is sucked by the immense gravity.
The size of the black hole is determined by the mass of collapsed stars. The critical radius of a non-rotating black hole is known as Schwarzschild radius, named after the German astronomer Karl Schwarzschild (1873-1916) studied the problem in 1916 on the basis of Einstein's theory of general relativity theory. Following the general theory of relativity, the gravity of a black hole bends space and time to such an extent in which they divided into a dimensionless body of infinite density.
The border around the collapsed star with this radius is known as "event horizon". Everything, whether it be light or matter of such border, forever lost within the black hole with no chance of escape. What happens beyond the event horizon, no one can say, because all laws of physics break and no longer apply. There are many theories, but little evidence to support them.
Black holes can not be seen, because they do not emit any electromagnetic radiation *. But they can be detected because of their impact on the surrounding stars.
In a binary star system, Cygnus X-1, (where the primary is a normal star of about 30 solar masses) by Doppler shifts from the system, it is assumed that there is a crew of about 10 to 15 solar masses orbiting the primary . There are X-ray emissions from the system, usually in connection with an "accretion disk" (a hot, dense disk of gas primarily star spiral down into the compact object orbiting the primary). There is evidence that the X-rays are emitted by the orbiting companion. Due to the mass of the companion object It is believed that this is a black hole.
The evidence of black holes is mounting, and it is now of the opinion that most galaxies a large enough size and our own may also have a black hole in its center.
* It is now known that black holes radiate the so-called Hawking radiation, this is a complex process, but also for those who are interested in a brief statement. Virtual particles are constantly generated couples near the horizon of the black hole as they are everywhere. Normally, they are a particle-antiparticle pair and they quickly destroy each other. But near the horizon of a black hole, it is possible that a decline before the destruction can happen, in which case the other escapes, as Hawking
Inside a star, there is a constant struggle between the pressure of active and passive gravity pressure from heat. If you were to throw an unopened can of soda in a fire, the drink would remove from the heat and explode. This is the same principle at work when a star is burning, its heat generated great pressure to the outside, but this constant explosion is by gravity, is just as strong, so that a star maintains its shape and size.
When a star is approaching the end of his life it slowly cools and the outside pressure is growing weaker and weaker as the temperature of the star drops. The passive pressure of the heat is almost over, the pressure from inside gravity and still depends on the size of the star. It is the theory that if a star is about ten times as large as our sun is approaching the end of his life, as it shrinks its own gravity pulls it slowly, but as soon as they are more and more dense the gravity is stronger.
The focus is so intense that not even light can escape. Have you ever seen a swirling water flow, then you have a pretty good idea what happened, like a black hole draws in. As things matter and light approach near a black hole slowly, they are in. If they do not tip, especially for the spatial anomaly then they are in a violent and unstable orbit around the black hole until the orbit decays and it is sucked by the immense gravity.
The size of the black hole is determined by the mass of collapsed stars. The critical radius of a non-rotating black hole is known as Schwarzschild radius, named after the German astronomer Karl Schwarzschild (1873-1916) studied the problem in 1916 on the basis of Einstein's theory of general relativity theory. Following the general theory of relativity, the gravity of a black hole bends space and time to such an extent in which they divided into a dimensionless body of infinite density.
The border around the collapsed star with this radius is known as "event horizon". Everything, whether it be light or matter of such border, forever lost within the black hole with no chance of escape. What happens beyond the event horizon, no one can say, because all laws of physics break and no longer apply. There are many theories, but little evidence to support them.
Black holes can not be seen, because they do not emit any electromagnetic radiation *. But they can be detected because of their impact on the surrounding stars.
In a binary star system, Cygnus X-1, (where the primary is a normal star of about 30 solar masses) by Doppler shifts from the system, it is assumed that there is a crew of about 10 to 15 solar masses orbiting the primary . There are X-ray emissions from the system, usually in connection with an "accretion disk" (a hot, dense disk of gas primarily star spiral down into the compact object orbiting the primary). There is evidence that the X-rays are emitted by the orbiting companion. Due to the mass of the companion object It is believed that this is a black hole.
The evidence of black holes is mounting, and it is now of the opinion that most galaxies a large enough size and our own may also have a black hole in its center.
* It is now known that black holes radiate the so-called Hawking radiation, this is a complex process, but also for those who are interested in a brief statement. Virtual particles are constantly generated couples near the horizon of the black hole as they are everywhere. Normally, they are a particle-antiparticle pair and they quickly destroy each other. But near the horizon of a black hole, it is possible that a decline before the destruction can happen, in which case the other escapes, as Hawking
Kamis, 19 Juni 2008
Identifying Star Clusters
The Pleiades, the Hyades and the Beehive Cluster, all surprising in their own right but, to pose a straightfoward question: What is it?
Imagine that you are detached from any kind of star chart. Yes, how other than the search for Ascension (RA) or declination (DEC), one could know where to search?
Star cluster M45, the Pleiades The Pleiades is also known by its Messier catalogue number, M45. Although nicknamed the Seven Sisters (identification card stars of the Pleiades), M45 is actually greater than 100 stars.
It is 3:47 in RA, DEC +24.07 with a visual brightness of 1.6, and the visible dimension of the arch 110.0 minutes.
The Hyades, also known as Melotte 25, see the RA 4:27, DEC +16 with a visual brightness .5 scale and visible dimension of the arch 330 minutes.
Both the Pleiades and Hyades are the open star cluster in the constellation Taurus (bull), and they may become apparent with the naked eye.
Find the Seven Sisters on the bull right shoulder. They are about 4 degrees from the elliptic, they are often occulted by the moon and other planets (which is a great observer Eye Candy). There are a lot of nebulosity is located within the Pleiades, especially around the brightest stars.
I enjoyed watching them seem to sit on the mountain summit, where I lived outside Mexico City. Greek mythology tells the story of the Pleiades in the sky, while the search for refuge of Orion's nonstop persecution.
The Hyades, 150 light years from Earth, outlines the face and bull is a loose V-shaped cluster of white stars. It is less densely populated and younger than the Pleiades. While the central STAR Group is about 10 light years in diameter of the outer group is over 80 light years. Astronomical studies on the sky show the Hyades moving east toward the sky Betelgeuse in Orion.
It should be noted that the bright red star Aldebaran (Alpha Tauri) - The eye of the bull - is not a member of this group are in the field despite the Hyades.
It is suspected that the Hyades May, a common origin with the Beehive Cluster (located in the constellation Cancer), due to similarities in their own movement and age.
The Beehive Cluster is RA-08: 40.1, DEC +19: 59, with a visual brightness of 3.7 magnitude and dimension of the visible arch 95.0 minutes. Known also as Praesepe (Latin for manger), it is Messier's No. M44. When it comes to observe, look for the superpower Binary Star TX Cancri. Epsilon Cancri is also a view Fang and worth spending some time.
Imagine that you are detached from any kind of star chart. Yes, how other than the search for Ascension (RA) or declination (DEC), one could know where to search?
Star cluster M45, the Pleiades The Pleiades is also known by its Messier catalogue number, M45. Although nicknamed the Seven Sisters (identification card stars of the Pleiades), M45 is actually greater than 100 stars.
It is 3:47 in RA, DEC +24.07 with a visual brightness of 1.6, and the visible dimension of the arch 110.0 minutes.
The Hyades, also known as Melotte 25, see the RA 4:27, DEC +16 with a visual brightness .5 scale and visible dimension of the arch 330 minutes.
Both the Pleiades and Hyades are the open star cluster in the constellation Taurus (bull), and they may become apparent with the naked eye.
Find the Seven Sisters on the bull right shoulder. They are about 4 degrees from the elliptic, they are often occulted by the moon and other planets (which is a great observer Eye Candy). There are a lot of nebulosity is located within the Pleiades, especially around the brightest stars.
I enjoyed watching them seem to sit on the mountain summit, where I lived outside Mexico City. Greek mythology tells the story of the Pleiades in the sky, while the search for refuge of Orion's nonstop persecution.
The Hyades, 150 light years from Earth, outlines the face and bull is a loose V-shaped cluster of white stars. It is less densely populated and younger than the Pleiades. While the central STAR Group is about 10 light years in diameter of the outer group is over 80 light years. Astronomical studies on the sky show the Hyades moving east toward the sky Betelgeuse in Orion.
It should be noted that the bright red star Aldebaran (Alpha Tauri) - The eye of the bull - is not a member of this group are in the field despite the Hyades.
It is suspected that the Hyades May, a common origin with the Beehive Cluster (located in the constellation Cancer), due to similarities in their own movement and age.
The Beehive Cluster is RA-08: 40.1, DEC +19: 59, with a visual brightness of 3.7 magnitude and dimension of the visible arch 95.0 minutes. Known also as Praesepe (Latin for manger), it is Messier's No. M44. When it comes to observe, look for the superpower Binary Star TX Cancri. Epsilon Cancri is also a view Fang and worth spending some time.
Meteors - Shooting Stars
What is a meteor?Meteors or shooting stars, as more widely known, the streaka of light produced when a Meteoroid burns in the atmosphere. It looks like a star falls to us, because they are flashing about us. The meteoroids, the meteors are dust and stones in space.
Comets and asteroids are the two main sources. In coming close to the sun, the comet dust and loose fragments, while losing asteroid fragments collide when read together. As the earth moves along its orbit in, meteoroids hit the upper atmosphere and hurtle toward Earth's surface. Once in the atmosphere, the friction between the Meteoroid and air molecules often produces short stretch of light that we call a meteor.
Most meteors typically measure 1m and over 20 km long and consists of a cylinder of excited atoms and molecules. They are usually from 120 to 80 km above the Earth's surface.
To make a meteor Meteoroid needed a mass of only one millionth of a gram, but at an enormous speed travel somewhere between 11 and 74km/sec (up to 100 times faster than a rifle bullet). The factors affecting the luminosity of a meteor, the size, speed, mass and structure of the Meteoroid material. Large meteoroids, which produce more meteors on a scale of -10 called fireballs. Tens of thousands of them fall to earth every year around five thousand which dissolve and explode. These meteors are called explosive cars.
Perseid meteor Around 220000 tonnes of space dust enters the atmosphere each year. Most of it is from the tiny particles, which produce meteors.
Sporadic meteors are either (a random meteor) or a shower (this is in the meteors occur regularly, with a projected date and time, from the same region of the sky, annually).
Meteor Showers
Meteor showers occur when the Earth moves through a stream of particles of a decaying comet. This is because comets store enormous amounts of material for each orbit. Some of the biggest surpluses and Halley Comet Encke. Meteoroid dust blown away from the comet nucleus of gas. Most will be lost if the comet is the closest to the sun. A meteor stream developed along the orbit of the comet and is always doing something completes other comets orbit the sun. If the parent comet finally disintegrates, it means the end for a certain power as they are not regularly renewed and its particles into space disperse.
As the earth moves along its orbit around the sun, it moves regularly through streams of meteoroids. Therefore Meteor showers are regular and predictable events, and there are more than 20 per year.
These showers can be used at specific times. In these few days, there is a maximum, a time when the hourly rate of meteors is to a maximum amount. Note that the exact date and time of the maximum differs slightly each year. The brightness of the moon in the night can greatly affect the number of meteors visible to the naked eye. The maximum hourly rate is the number of meteors seen by an observer, has the best conditions to watch.
Another important point which is important in the advertisement meteors, is the position of the radiant heat. The radiated power is the point in the sky, from which a specific shower meteors seem to radiate. The constellation in the radiant heat of a particular shower is also its name, as the radiant heat of the Leonids is in Leo. The meteors in a shower are indeed travel in parallel lines, they seem only to radiate from a point, since train tracks appear to radiate from a point, since train tracks appear to radiate from a point in the distance.
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