Tag: astronomy
Tracing the Canals of Mars
Water from comets
New results using the Herschel Space Telescope suggest that Earth’s water was brought here by comets.
New results using the Herschel Space Telescope suggest that Earth’s water was brought here by comets.
Astronomers have found a dozen supernovae taking place closer to the Big Bang than ever detected.
Astronomers have found a dozen supernovae taking place only a few billion years after the Big Bang.
[The results suggest that these types of supernovae] were exploding about five times more frequently 10 billion years ago than they are today. These supernovas are a major source of iron in the universe, the main component of the Earth’s core and an essential ingredient of the blood in our bodies.
Astronomers have found a dozen supernovae taking place only a few billion years after the Big Bang.
[The results suggest that these types of supernovae] were exploding about five times more frequently 10 billion years ago than they are today. These supernovas are a major source of iron in the universe, the main component of the Earth’s core and an essential ingredient of the blood in our bodies.
Aden Meinel, astronomer and innovator, has passed away
Aden Meinel, astronomer and innovator, has passed away.
Meinel, first director of the Kitt Peak Observatory, was the also first to conceive and try to build robotic telescopes that could be operated remotely. Many of his ideas were later incorporated both on the ground and in space.
Aden Meinel, astronomer and innovator, has passed away.
Meinel, first director of the Kitt Peak Observatory, was the also first to conceive and try to build robotic telescopes that could be operated remotely. Many of his ideas were later incorporated both on the ground and in space.
The 2011 Nobel Prize for Physics has been awarded
The 2011 Nobel Prize for Physics has been awarded to the astronomers who discovered dark energy.
Saul Perlmutter from the Lawrence Berkeley National Laboratory and University of California, Berkeley, has been awarded half of this year’s prize for his work on the Supernova Cosmology Project, with the other half awarded to Brian P. Schmidt from the Australian National University and Adam G. Riess from the Johns Hopkins University and Space Telescope Science Institute, Baltimore, for their work on the High-z Supernova Search Team.
The 2011 Nobel Prize for Physics has been awarded to the astronomers who discovered dark energy.
Saul Perlmutter from the Lawrence Berkeley National Laboratory and University of California, Berkeley, has been awarded half of this year’s prize for his work on the Supernova Cosmology Project, with the other half awarded to Brian P. Schmidt from the Australian National University and Adam G. Riess from the Johns Hopkins University and Space Telescope Science Institute, Baltimore, for their work on the High-z Supernova Search Team.
For an extraterrestrial skiing experience, Enceladus is the place to go.
Dawn begins close-up orbit observations
Dawn begins close-up orbit observations of Vesta. More new results here.
In this orbit, the average distance from the spacecraft to the Vesta surface is 420 miles (680 kilometers), which is four times closer than the previous survey orbit.
Dawn begins close-up orbit observations of Vesta. More new results here.
In this orbit, the average distance from the spacecraft to the Vesta surface is 420 miles (680 kilometers), which is four times closer than the previous survey orbit.
The world’s largest radio telescope has opened its eyes
The world’s largest radio telescope has opened its eyes.
The world’s largest radio telescope has opened its eyes.
NASA has identified ninety percent of the largest near-Earth asteroids
Data from the infrared telescope WISE has now identified ninety percent of the largest near-Earth asteroids.
NASA researchers also downgraded their estimate of the number of medium-sized asteroids, saying there are 44 percent fewer than previously believed. The downside is that scientists have yet to find many of these mid-sized asteroids, which could destroy a metropolitan city.
Data from the infrared telescope WISE has now identified ninety percent of the largest near-Earth asteroids.
NASA researchers also downgraded their estimate of the number of medium-sized asteroids, saying there are 44 percent fewer than previously believed. The downside is that scientists have yet to find many of these mid-sized asteroids, which could destroy a metropolitan city.
The coming blindness of astronomy
The European Southern Observatory today released this infrared image today of what astronomers have named the Fried Egg Nebula. Taken by the Very Large Telescope in Chile, the picture shows the concentric dust shells surrounding a post-red supergiant star, thought to be transitioning to the next stage of stellar evolution called a yellow hypergiant. As the press release explains,
The monster star, known to astronomers as IRAS 17163-3907, has a diameter about a thousand times bigger than our Sun. At a distance of about 13 000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500 000 times more brightly than the Sun. . . . If the Fried Egg Nebula were placed in the centre of the Solar System the Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10 000 times the distance from the Earth to the Sun.
Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.
According to the science paper [pdf] describing this research, the stage of yellow hypergiants is a preliminary to the star evolving into a luminous blue variable, of which Eta Carinae is the most famous. In this next stage a star is thought to have a good chance of going supernova.
Though this image is truely spectacular, taken by a ground-based telescope of a star 13,000 light years away, what I find most significant about this image is its fuzziness. It reminds me of the kind of images astronomers and the public routinely accepted as the best possible, before the launch of the Hubble Space Telescope.
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NASA science administrator Ed Weiler is retiring after 33 years
Science administrator Ed Weiler is retiring after almost 33 years at NASA.
Among Weiler’s many achievements, he was crucial to getting the Hubble Space Telescope launched. Even more important, though others had conceived the idea of using the shuttle to maintain Hubble, he designed the maintenance schedule for the telescope. Seven years before it was launched, he insisted that a regular schedule of repair missions be placed on the shuttle manifest. He also insisted that a duplicate of the telescope’s main camera be built, so that if anything went wrong with the first a repaired unit could be launched quickly. It was his foresight here that made the first repair of Hubble in December 1993 go so smoothly. For this, astronomers will always be grateful.
Science administrator Ed Weiler is retiring after almost 33 years at NASA.
Among Weiler’s many achievements, he was crucial to getting the Hubble Space Telescope launched. Even more important, though others had conceived the idea of using the shuttle to maintain Hubble, he designed the maintenance schedule for the telescope. Seven years before it was launched, he insisted that a regular schedule of repair missions be placed on the shuttle manifest. He also insisted that a duplicate of the telescope’s main camera be built, so that if anything went wrong with the first a repaired unit could be launched quickly. It was his foresight here that made the first repair of Hubble in December 1993 go so smoothly. For this, astronomers will always be grateful.
The Accelerating Universe and Dark Energy Might Be Illusions
The uncertainty of science: A new theory posits that the accelerating universe and dark energy might be illusions caused by motion of our galaxy through space.
The uncertainty of science: A new theory posits that the accelerating universe and dark energy might be illusions caused by motion of our galaxy through space.
A second large satellite will rain debris down in October
Even if UARS misses you today, don’t relax! A second large satellite, the 2.4 ton ROSAT X-Ray space telescope, is going to rain debris down late in October or early November.
On its ROSAT website, DLR estimates that “up to 30 individual debris items with a total mass of up to 1.6 tonnes might reach the surface of the Earth. The X-ray optical system, with its mirrors and a mechanical support structure made of carbon-fibre reinforced composite – or at least a part of it – could be the heaviest single component to reach the ground.”
Even if UARS misses you today, don’t relax! A second large satellite, the 2.4 ton ROSAT X-Ray space telescope, is going to rain debris down late in October or early November.
On its ROSAT website, DLR estimates that “up to 30 individual debris items with a total mass of up to 1.6 tonnes might reach the surface of the Earth. The X-ray optical system, with its mirrors and a mechanical support structure made of carbon-fibre reinforced composite – or at least a part of it – could be the heaviest single component to reach the ground.”
Astronomers argue about the legitimacy of the first exoplanet to be directly imaged
Astronomers question the legitimacy of the first exoplanet to be directly imaged.
Astronomers question the legitimacy of the first exoplanet to be directly imaged.
WISE telescope raises questions about asteroid that is thought to have killed dinosaurs
The WISE space telescope has raised questions about source of the asteroid believed to have killed the dinosaurs.
The WISE space telescope has raised questions about source of the asteroid believed to have killed the dinosaurs.
New exoplanets make astronomers long for a telescope to see them
The plethora of new exoplanet discoveries has astronomers longing for a telescope that can see them up close.
Astronomers need either a giant space telescope equipped with a device for blocking starlight, or an interferometer, consisting of several telescopes flying in formation. NASA did develop a proposal for such a space telescope, called Terrestrial Planet Finder, and the European Space Agency hoped to fly a similar mission called Darwin. But budgetary constraints have left both missions in limbo, unlikely to advance to the front of either agency’s queue until well into the next decade. At the conference, Traub raised the issue. “People are not thinking deeply about the distant future. People are wrapped up with what they’re doing right now,” he says. “Clearly, I’m concerned.”
The plethora of new exoplanet discoveries has astronomers longing for a telescope that can see them up close.
Astronomers need either a giant space telescope equipped with a device for blocking starlight, or an interferometer, consisting of several telescopes flying in formation. NASA did develop a proposal for such a space telescope, called Terrestrial Planet Finder, and the European Space Agency hoped to fly a similar mission called Darwin. But budgetary constraints have left both missions in limbo, unlikely to advance to the front of either agency’s queue until well into the next decade. At the conference, Traub raised the issue. “People are not thinking deeply about the distant future. People are wrapped up with what they’re doing right now,” he says. “Clearly, I’m concerned.”
Webb Telescope budget continues to grow
Bad news for astronomers: The budget for the James Webb Space Telescope continues to swell.
Bad news for astronomers: The budget for the James Webb Space Telescope continues to swell.
A Yellow Supergiant Progenitor of a Massive Star Supernova in M51
The uncertainty of science: Astronomers have determined that the star that went supernova in the Whirlpool Galaxy (M51) in June — making it the nearest supernova in 25 years — was a yellow supergiant star, not an aging red supergiant as predicted by theory. From the preprint paper:
Despite the canonical prediction that Type II supernovae arise from red supergiants, there is mounting evidence that some stars explode as yellow supergiants. A handful of Type II supernovae have been observed to arise from yellow supergiants: supernovae 1993J, 2008cn, and 2009kr. The locations of the progenitors on the Hertzsprung-Russell diagram shows clearly that these stars are not located on the predicted end points for single star stellar evolution tracks. In addition, despite arising from supposedly similar yellow supergiant progenitors, these supernovae display a wide range of properties.
The Hertzsprung-Russell diagram is a graph mapping the color of stars against their luminosity. Because color and brightness change as the star evolves over time, the graph is used by astronomers to track the birth, growth, and death of stars. That these yellow supergiants don’t appear to be at “the predicted end points for single star evolution” on the diagram is a serious problem for the theorists who have tried to explain what causes this particular type of supernova.
Which also means astronomers are still unable to tell us what stars in the sky are most likely to go supernova in the future.
The uncertainty of science: Astronomers have determined that the star that went supernova in the Whirlpool Galaxy (M51) in June — making it the nearest supernova in 25 years — was a yellow supergiant star, not an aging red supergiant as predicted by theory. From the preprint paper:
Despite the canonical prediction that Type II supernovae arise from red supergiants, there is mounting evidence that some stars explode as yellow supergiants. A handful of Type II supernovae have been observed to arise from yellow supergiants: supernovae 1993J, 2008cn, and 2009kr. The locations of the progenitors on the Hertzsprung-Russell diagram shows clearly that these stars are not located on the predicted end points for single star stellar evolution tracks. In addition, despite arising from supposedly similar yellow supergiant progenitors, these supernovae display a wide range of properties.
The Hertzsprung-Russell diagram is a graph mapping the color of stars against their luminosity. Because color and brightness change as the star evolves over time, the graph is used by astronomers to track the birth, growth, and death of stars. That these yellow supergiants don’t appear to be at “the predicted end points for single star evolution” on the diagram is a serious problem for the theorists who have tried to explain what causes this particular type of supernova.
Which also means astronomers are still unable to tell us what stars in the sky are most likely to go supernova in the future.
Update on the repairs to the Subaru Telescope
The Subaru Telescope team has posted an update on its repair effort following a July 2nd coolant leak.
The Subaru Telescope team has posted an update on its repair effort following a July 2nd coolant leak.
A Smartphone ap to weigh galaxies
Want to known how much a galaxy weighs? There is now an Android smartphone application, GalMass, for calculating it!
Want to known how much a galaxy weighs? There is now an Android smartphone application, GalMass, for calculating it!
A planet with two suns
Has Dark Matter been detected?
A slew of exoplanets
Using two European-built ground-based telescopes in Chile, astronomers have announced today the discovery of 50 new exoplanets, 16 of which are considered super Earths, one of which is in the habitable zone of its star. You can read the preprint of their research paper here [pdf].
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A giant storm on a distant star
Astronomers have spotted what they think is a giant storm on a distant star.
As part of a large survey of nearby brown dwarfs – objects that occupy the mass gap between dwarf stars and giant planets – the scientists used an infrared camera on the 2.5m telescope at Las Campanas Observatory in Chile to capture repeated images of a brown dwarf dubbed 2MASS J21392676+0220226, or 2MASS 2139 for short, over several hours. In that short time span, they recorded the largest variations in brightness ever seen on a cool brown dwarf.
“We found that our target’s brightness changed by a whopping 30 per cent in just under eight hours,” said PhD candidate Jacqueline Radigan, lead author of a paper to be presented this week at the Extreme Solar Systems II conference in Jackson Hole, Wyoming and submitted to the Astrophysical Journal. “The best explanation is that brighter and darker patches of its atmosphere are coming into our view as the brown dwarf spins on its axis,” said Radigan.
Astronomers have spotted what they think is a giant storm on a distant star.
As part of a large survey of nearby brown dwarfs – objects that occupy the mass gap between dwarf stars and giant planets – the scientists used an infrared camera on the 2.5m telescope at Las Campanas Observatory in Chile to capture repeated images of a brown dwarf dubbed 2MASS J21392676+0220226, or 2MASS 2139 for short, over several hours. In that short time span, they recorded the largest variations in brightness ever seen on a cool brown dwarf.
“We found that our target’s brightness changed by a whopping 30 per cent in just under eight hours,” said PhD candidate Jacqueline Radigan, lead author of a paper to be presented this week at the Extreme Solar Systems II conference in Jackson Hole, Wyoming and submitted to the Astrophysical Journal. “The best explanation is that brighter and darker patches of its atmosphere are coming into our view as the brown dwarf spins on its axis,” said Radigan.
Twin GRAIL gravity probes on the way to the moon
The twin GRAIL gravity probes launched successfully on Saturday and are now on their way to the moon.
The twin GRAIL gravity probes launched successfully on Saturday and are now on their way to the moon.
Symphony of Science
Unknown objects in space
NASA’s Fermi Gamma-Ray Telescope today released an updated catalog of the last two years of its survey of the sky at high energy emissions. All told, there are 1873 objects in the catalog, more than half of which are supermassive black holes at the center of distant galaxies. You can see this all-sky map below the fold.
Many of the objects are quite familiar, such as the Crab Nebula, the remnant of a supernova that exploded a little less than a thousand years ago.
For decades, most astronomers regarded the Crab Nebula as the steadiest beacon at X-ray energies. But data from several orbiting instruments — including Fermi’s Gamma-ray Burst Monitor — now show unexpected variations. Astronomers have shown that since 2008, the nebula has faded by 7 percent at high energies, a reduction likely tied to the environment around its central neutron star.
Since 2007, Fermi and the Italian Space Agency’s AGILE satellite have detected several short-lived gamma-ray flares at energies hundreds of times higher than the nebula’s observed X-ray variations. In April, the satellites detected two of the most powerful yet recorded. To account for these “superflares,” scientists say that electrons near the pulsar must be accelerated to energies a thousand trillion times greater than that of visible light — and far beyond what can be achieved by the Large Hadron Collider near Geneva, Switzerland, now the most powerful particle accelerator on Earth.
What I, and many astronomers, find even most interesting about this catalog, however, is the large number of completely mysterious objects scattered across the sky, objects that emit powerful gamma rays but are not visible in any other wavelengths. All told, these unidentified objects comprise almost one third of the entire catalog.
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Nearest supernova in a quarter century now visible with binoculars
The nearest supernova in almost a quarter century is now visible using binoculars.
The nearest supernova in almost a quarter century is now visible using binoculars.
Baby Star Found on Earth’s Doorstep
A baby star has been found only 27 light years away.
AP Columbae lies in the constellation Columba the Dove, south of the brilliant constellation Orion. “AP Columbae is still contracting under gravity towards the main sequence,” says astronomer Adric Riedel of Georgia State University in Atlanta, whose team measured the star’s parallax—an indication of its distance—and discovered that the star is abnormally luminous. Although the star is dim and red, it’s four times as bright as it should be, because it’s twice the diameter of a main-sequence star of the same color.
A baby star has been found only 27 light years away.
AP Columbae lies in the constellation Columba the Dove, south of the brilliant constellation Orion. “AP Columbae is still contracting under gravity towards the main sequence,” says astronomer Adric Riedel of Georgia State University in Atlanta, whose team measured the star’s parallax—an indication of its distance—and discovered that the star is abnormally luminous. Although the star is dim and red, it’s four times as bright as it should be, because it’s twice the diameter of a main-sequence star of the same color.
Kepler team pushes for mission extension
The Kepler team pushes for a mission extension in order to find Earth-sized planets.
The Kepler spacecraft has hit an unexpected obstacle as it patiently watches the heavens for exoplanets: too many rowdy young stars. The orbiting probe detects small dips in the brightness of a star that occur when a planet crosses its face. But an analysis of some 2,500 of the tens of thousands of Sun-like stars detected in Kepler’s field of view has found that the stars themselves flicker more than predicted, with the largest number varying twice as much as the Sun. That makes it harder to detect Earth-sized bodies. As a result, the analysis suggests that Kepler will need more than double its planned mission life of three-and-a-half years to achieve its main goal of determining how common Earth-like planets are in the Milky Way.
While it is important to find those Earth-sized planets, to me the important discovery here is that Kepler is confirming what previous research has suggested: Stars like our Sun are generally far more active and variable than the Sun itself. Which means that either the Sun is unusual, or has been unusually inactive during recorded human history.
The Kepler team pushes for a mission extension in order to find Earth-sized planets.
The Kepler spacecraft has hit an unexpected obstacle as it patiently watches the heavens for exoplanets: too many rowdy young stars. The orbiting probe detects small dips in the brightness of a star that occur when a planet crosses its face. But an analysis of some 2,500 of the tens of thousands of Sun-like stars detected in Kepler’s field of view has found that the stars themselves flicker more than predicted, with the largest number varying twice as much as the Sun. That makes it harder to detect Earth-sized bodies. As a result, the analysis suggests that Kepler will need more than double its planned mission life of three-and-a-half years to achieve its main goal of determining how common Earth-like planets are in the Milky Way.
While it is important to find those Earth-sized planets, to me the important discovery here is that Kepler is confirming what previous research has suggested: Stars like our Sun are generally far more active and variable than the Sun itself. Which means that either the Sun is unusual, or has been unusually inactive during recorded human history.