Astronomy blog

September 2, 2008, 8:40 PM CT

The Thousand-Ruby Galaxy

This dramatic image of the galaxy Messier 83 was captured by the Wide Field Imager at ESO's La Silla Observatory, located high in the dry desert mountains of the Chilean Atacama Desert. Messier 83 lies roughly 15 million light-years away towards the huge southern constellation of Hydra (the sea serpent). It stretches over 40 000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies.

This very detailed image shows the spiral arms of Messier 83 adorned by countless bright flourishes of ruby red light. These are in fact huge clouds of glowing hydrogen gas. Ultraviolet radiation from newly born, massive stars is ionising the gas in these clouds, causing the great regions of hydrogen to glow red. These star forming regions are contrasted dramatically in this image against the ethereal glow of older yellow stars near the galaxy's central hub. The image also shows the delicate tracery of dark and winding dust streams weaving throughout the arms of the galaxy.

Messier 83 was discovered by the French astronomer Nicolas Louis de Lacaille in the mid 18th century. Decades later it was listed in the famous catalogue of deep sky objects compiled by another French astronomer and famous comet hunter, Charles Messier. Recent observations of this enigmatic galaxy in ultraviolet light and radio waves have shown that even its outer desolate regions (farther out than those seen in this image) are populated with baby stars. X-ray observations of the heart of Messier 83 have shown that its centre is a hive of vigorous star formation, held deep within a cloud of superheated gas, with temperatures of 7 million degrees Celsius. Messier 83 is also one of the most prolific producers of supernovae, that is, exploding stars: this is one of the two galaxies, which had 6 supernovae in the past 100 years. One of these, SN 1957D was observable for 30 years!......... Posted by: Sean      Read more         Source

August 27, 2008, 8:52 PM CT

Clash of Clusters Provides Another Clue to Dark Matter

Another powerful collision of galaxy clusters has been captured with NASA's Chandra X-ray Observatory and Hubble Space Telescope. Like its famous cousin, the so-called Bullet Cluster, this clash of clusters provides striking evidence for dark matter and insight into its properties.

Like the Bullet Cluster, this newly studied cluster, officially known as MACS J0025.4-1222, shows a clear separation between dark and ordinary matter. This helps answer a crucial question about whether dark matter interacts with itself in ways other than via gravitational forces.

This finding is important because it independently verifies the results found for the Bullet Cluster in 2006. The new results show the Bullet Cluster is not an exception and that the earlier results were not the product of some unknown error.

Just like the original Bullet Cluster, MACS J0025 formed after an incredibly energetic collision between two large clusters in almost the plane of the sky. In some ways, MACS J0025 can be thought of as a prequel to the Bullet Cluster. At its much larger distance of 5.7 billion light years, astronomers are witnessing a collision that occurred long before the Bullet Cluster's.

Using optical images from Hubble, the team was able to infer the distribution of the total mass (colored in blue) -- dark and ordinary matter -- using a technique known as gravitational lensing. The Chandra data enabled the astronomers to accurately map the position of the ordinary matter, mostly in the form of hot gas, which glows brightly in X-rays (pink.)......... Posted by: Sean      Read more         Source

August 27, 2008, 7:07 PM CT

Collision of galaxy clusters captured

Two UC Santa Barbara astronomers are part of a team that has made a stunning discovery using the Hubble Space Telescope and Chandra X-ray Observatory, it was announced recently by the National Aeronautics and Space Administration.

The capture of a collision of galaxy clusters was made by a team led by Marusa Bradac, a postdoctoral researcher and Hubble fellow in UCSB's Department of Physics. The international team also included Tommaso Treu, assistant professor of physics at UCSB.

"It is in our view an important step forward to understanding the properties of the mysterious dark matter," Bradac said. "Dark matter makes up five times more matter in the universe than ordinary matter. This study confirms that we are dealing with a very different kind of matter, unlike anything that we are made of. And were able to study it in a very powerful collision of two clusters of galaxies".

Below is the complete text of the press release issued today by NASA.

(Cambridge, Mass.) A powerful collision of galaxy clusters has been captured with NASA's Chandra X-ray Observatory and Hubble Space Telescope. Like its famous cousin, the so-called Bullet Cluster, this clash of clusters provides striking evidence for dark matter and insight into its properties......... Posted by: Sean      Read more         Source

July 16, 2008, 7:54 PM CT

Diverse, Wet Environments on Ancient Mars

Mars once hosted vast lakes, flowing rivers and a variety of other wet environments that had the potential to support life, as per two new studies based on data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and other instruments on board NASA's Mars Reconnaissance Orbiter (MRO).

"The big surprise from these new results is how pervasive and long-lasting Mars' water was, and how diverse the wet environments were," says Scott Murchie, CRISM's principal investigator at the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md.

One study, reported in the July 17 issue of Nature, shows that vast regions of the ancient highlands of Mars-which cover about half the planet-contain clay minerals, which can form only in the presence of water. Volcanic lavas buried the clay-rich regions during subsequent, drier periods of the planet's history, but impact craters later exposed them at thousands of locations across the planet.

The clay-like minerals, called phyllosilicates, preserve a record of the interaction of water with rocks dating back to what is called the Noachian period of Mars' history, about 4.6 to 3.8 billion years ago. This period corresponds to the earliest years of the solar system, when Earth, the moon and Mars sustained a cosmic bombardment by comets and asteroids. Rocks of this age have largely been destroyed on Earth by plate tectonics; they are preserved on the moon, but were never exposed to liquid water. The phyllosilicate-containing rocks on Mars therefore preserve a unique record of liquid water environments-possibly suitable for life-in the early solar system......... Posted by: Sean      Read more         Source

July 16, 2008, 7:43 PM CT

A new method to weigh giant black holes

How do you weigh the biggest black holes in the universe? One answer now comes from a new and independent technique that UC Irvine researchers and other astronomers have developed using data from NASA's Chandra X-ray Observatory.

By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, researchers have determined the mass of the galaxy's supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique.

Astronomers have been seeking different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the sun. Until now, methods based on observing the motions of stars or of gas in a disk near such large black holes had been used.

"This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey, leader of the study and an assistant project scientist in the Department of Physics and Astronomy at UCI. David Buote, associate professor of physics and astronomy at UCI, also worked on this study.

"It is reassuring that two very different ways to measure the mass of a big black hole give such similar answers," Humphrey said......... Posted by: Sean      Read more         Source

July 10, 2008, 8:20 PM CT

Nano-sized Electronic Circuit To Universe

A newly developed nano-sized electronic device is an important step toward helping astronomers see invisible light dating from the creation of the universe. This invisible light makes up 98% of the light emitted since the "big bang," and may provide insights into the earliest stages of star and galaxy formation almost 14 billion years ago.

The tiny, new circuit, developed by physicsts at Rutgers University, NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the State University of New York at Buffalo, is 100 times smaller than the thickness of a human hair. It is sensitive to faint traces of light in the far-infrared spectrum (longest of the infrared wavelengths), well beyond the colors humans see.

"In the expanding universe, the earliest stars move away from us at a speed approaching the speed of light," said Michael Gershenson, professor of physics at Rutgers and one of the lead investigators. "As a result, their light is strongly red-shifted when it reaches us, appearing infrared".

Because the Earth's atmosphere strongly absorbs far-infrared light, Earth-based radiotelescopes cannot detect the very faint light emitted by these stars. So researchers are proposing a new generation of space telescopes to gather this light. Yet to take full advantage of space-borne telescopes, detectors that capture the light will have to be far more sensitive than any that exist today......... Posted by: Sean      Read more         Source

Tue, 08 Jul 2008 22:41:58 GMT

Cern's Large Hadron Collider, a big bang

Now here''s a gadget. In fact not just a gadget, but arguably the gadget. It''s the Large Hadron Collider at Cern, the European laboratory for particle physics near Geneva, scheduled to have its Grand Opening next month.

Stephen Hawking explains what the LHC is for:
"It will smash particles together to recreate the moments after the big bang, producing a new golden age of discovery for physicists."

There''s more, lots more, and the Guardian has just unveiled a group of articles and multimedia and podcasts that explains it all. Posted by: Sarah      Read more     Source

July 3, 2008, 9:21 PM CT

Einstein's Theory Passes Strict, New Test

Taking advantage of a unique cosmic configuration, astronomers have measured an effect predicted by Albert Einstein's theory of General Relativity in the extremely strong gravity of a pair of superdense neutron stars. Essentially, the famed physicist's 93-year-old theory passed yet another test.

Researchers at McGill University used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to do a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves.

"Of about 1700 known pulsars, this is the only case in which two pulsars orbit around each other," said Rene Breton, a graduate student at McGill University in Montreal, Canada. In addition, the stars' orbital plane is aligned nearly perfectly with their line of sight to the Earth. This causes the signal of one to be blocked, or eclipsed, as it circles the other.

"Those eclipses are the key to making a measurement that could never be done before," Breton said.

Einstein's 1915 theory predicted that in a close system of two very massive objects, such as neutron stars, one object's gravitational tug, along with an effect of its spinning around its axis, should cause the spin axis of the other to wobble, or precess......... Posted by: Sean      Read more         Source

June 18, 2008, 8:51 PM CT

Newly Born Twin Stars Are Far From Identical

Two stars, each with the same mass and in orbit around each other, are twins that one would expect to be identical. So astronomers were surprised when they discovered that twin stars in the Orion Nebula, a well-known stellar nursery 1,500 light years away, were not identical at all. In fact, these stars exhibited significant differences in brightness, surface temperature and possibly even size.

The study, which is reported in the June 19 issue of the journal Nature, suggests that one of the stars formed significantly earlier than its twin. Because astrophysicists have assumed that binary stars form simultaneously, the discovery provides an important new challenge for today's star formation theories, forcing theorists to reexamine their models to see if the models can indeed produce binaries with stars that form at different times.

Because mass and age estimates for stars less than a few million years old are based on models that were calibrated with measurements of binary stars presumed to have formed simultaneously, this new discovery may cause astronomers to readjust their estimates for thousands of young stars.

The newly formed twin stars are about 1 million years old. With a full lifespan of about 50 billion years, that makes them equivalent to one-day-old human babies......... Posted by: Sean      Read more         Source

June 4, 2008, 10:41 PM CT

Making A Giant Lunar Telescopes

Researchers working at NASA's Goddard Space Flight Center in Greenbelt, Md., have concocted an innovative recipe for giant telescope mirrors on the Moon. To make a mirror that dwarfs anything on Earth, just take a little bit of carbon, throw in some epoxy, and add lots of lunar dust.

"We could make huge telescopes on the moon relatively easily, and avoid the large expense of transporting a large mirror from Earth," says Peter Chen of NASA Goddard and the Catholic University of America, which is located in Washington, D.C. "Since most of the materials are already there in the form of dust, you don't have to bring very much stuff with you, and that saves a ton of money."

Chen and his Goddard colleagues Douglas Rabin, Michael Van Steenberg, and Ron Oliversen are presenting their mirror-making technique in a poster at the 212th meeting of the American Astronomical Society in St. Louis, Mo. They will also describe their results in a press conference on Wednesday, June 4 at 9:30 a.m. CDT.

For years, Chen had been working with carbon-fiber composite materials to produce high-quality telescope mirrors. But Chen and colleagues decided to try an experiment. They substituted carbon nanotubes (tiny tubular structures made of pure carbon) for the carbon-fiber composites. When they mixed small amounts of carbon nanotubes and epoxies (glue-like materials) with crushed rock that has the same composition and grain size as lunar dust, they discovered to their surprise that they had created a very strong material with the consistency of concrete. This material can be used instead of glass to make mirrors......... Posted by: Sean      Read more         Source

May 27, 2008, 10:19 PM CT

The Little Man and the Cosmic Cauldron

On the occasion of the 10th anniversary of the Very Large Telescope's First Light, ESO is releasing two stunning images of different kinds of nebulae, located towards the Carina constellation. The first one, Eta Carinae, has the shape of a 'little man' and surrounds a star doomed to explode within the next 100 000 years. The second image features a much larger nebula, whose internal turmoil is created by a cluster of young, massive stars.

Being brighter than one million Suns, Eta Carinae is the most luminous star known in the Galaxy. It is the closest example of a luminous blue variable, the last phase in the life of a very massive star before it explodes in a fiery supernova.

Eta Carinae is surrounded by an expanding bipolar cloud of dust and gas known as the Homunculus ('little man' in Latin), which astronomers believe was expelled from the star during a great outburst seen in 1843 [1].

Eta Carinae was one of the first objects to be imaged during First Light with ESO's VLT, 10 years ago. At the time, the image obtained with a test camera already showed the unique capabilities of the European flagship telescope for ground-based optical and infrared astronomy, as well as of its unique location on the mountain of Paranal. The image had a resolution of 0.38 arcseconds......... Posted by: Sean      Read more         Source

May 27, 2008, 10:16 PM CT

Seeking Answers To Asteroid Deflection

An Asteroid Deflection Research Center (ADRC) has been established on the Iowa State campus to bring scientists from around the world to develop asteroid deflection technologies. The center was signed into effect in April by the Office of the Executive Vice President and Provost.

"In the early part of 1990s, researchers around the world initiated studies to assess and devise methods to prevent near-Earth objects from striking Earth," said Bong Wie, the Vance D. Coffman Chair Professor in Aerospace Engineering and director of the center. "However, it is now 2008, and there is no consensus on how to reliably deflect them in a timely manner," he noted.

Wie, whose research expertise includes space vehicle dynamics and control, modeling and control of large space structures, and solar sail flight control system development and mission design, joined the Iowa State faculty last August. "I am very happy that Professor Bong Wie has joined the faculty at ISU," said Elizabeth Hoffman, executive vice president and provost. "His work on asteroid deflection is exciting and of great importance."

The ADRC will host an International Symposium on Asteroid Deflection Technology in fall 2008. Researchers and engineers from NASA, the European Space Agency, academia, and the aerospace industry will be invited to the Iowa State campus to formulate a roadmap for developing asteroid deflection technologies......... Posted by: Sean      Read more         Source

May 21, 2008, 9:50 PM CT

Why do astronauts suffer from space sickness?

Rotating astronauts for a lengthy period provided researcher Suzanne Nooij with better insight into how 'space sickness' develops, the nausea and disorientation experienced by a number of astronauts. Nooij will receive her PhD from TU Delft on this subject on Tuesday 20 May.

Gravity plays a major role in our spatial orientation. Changes in gravitational forces, such as the transition to weightlessness during a space voyage, influence our spatial orientation and require adaptation by a number of of the physiological processes in which our balance system plays a part. As long as this adaptation is incomplete, this can be coupled to motion sickness (nausea), visual illusions and disorientation.

This 'space sickness' or Space Adaptation Syndrome (SAS), is experienced by about half of all astronauts during the first few days of their space voyage. Wubbo Ockels, the first Dutchman in space in 1986, also suffered from these symptoms. In his capacity as TU Delft professor, Ockels is PhD supervisor for Suzanne Nooij's research.

Rotation.

Interestingly, SAS symptoms can even be experienced after lengthy exposure to high gravitational forces in a human centrifuge, as is used for instance for testing and training fighter pilots. To experience this, people have to spend longer than an hour in a centrifuge and be subjected to gravitational forces of three times higher than that on Earth. The rotation is in itself not unpleasant, but after leaving the centrifuge about half of the test subjects experience the same symptoms as caused by space sickness. It also turns out that astronauts who suffer from space sickness during space flights also experience these symptoms following lengthy rotation on Earth. This means that these symptoms are not caused by weightlessness as such, but more generally by adaptation to a different gravitational force......... Posted by: Sean      Read more         Source

May 21, 2008, 8:45 PM CT

Storm Winds Blow in Jupiter's Little Red Spot

Using data from NASA's New Horizons spacecraft and two telescopes at Earth, an international team of researchers has observed that one of the solar system's largest and newest storms - Jupiter's Little Red Spot - has some of the highest wind speeds ever detected on any planet.

The New Horizons scientists combined observations from their Pluto-bound spacecraft, which flew past Jupiter in February 2007; data from the Hubble Space Telescope orbiting Earth, and the European Southern Observatory's Very Large Telescope, perched on an Atacama Desert mountain in Chile. This is the first time that high resolution, close-up imaging of the Little Red Spot has been combined with powerful Earth-orbital and ground-based imagery made at ultraviolet through mid-infrared wavelengths.

Jupiter's "LRS" is an anticyclone, a storm whose winds circulate in the opposite direction to that of a cyclone - counterclockwise, in this case. It is nearly the size of Earth and as red as the similar, but larger and more well known, Great Red Spot (or GRS). The dramatic evolution of the LRS began with the merger of three smaller white storms that had been observed since the 1930s. Two of these storms coalesced in 1998, and the combined pair merged with a third major Jovian storm in 2000. In late 2005 - for reasons still unknown - the combined storm turned red......... Posted by: Sean      Read more         Source

May 19, 2008, 8:21 PM CT

Common star draws swift attention with unprecedented flare

On April 25, one of our nearest stellar neighbors, a small, faint red dwarf known as EV Lacertae, unleashed the brightest flare ever detected from a normal star outside our solar system. The monster blast of radiation was picked up with NASA's Swift satellite, which scans space looking for Gamma-ray bursts coming from the edge of the universe.

"The sheer magnitude of this stellar flare is unprecedented, and it was produced in our own celestial back yard by a star of the most common type," said Rachel Osten, a Hubble Fellow at the University of Maryland and NASA's Goddard Space Flight Center in Greenbelt, Md.

Though EV Lacertae is only 16 light-years from Earth, it's not visible in the night sky. It is much cooler than the sun and shines with only one percent of the sun's light. The star's faint magnitude-10 glow is far below naked-eye visibility. However, the flare, which packed the power of thousands of solar flares, would have made it easy to see EV Lacertae had it occurred when the star was observably positioned in the night sky.

It's in the Spin

As per Osten, who studies nearby stars, EV Lacertae is young, with an estimated age of some 300 hundred million years, and small with a mass and diameter only about a third that of the sun. However, it rotates much faster than the sun, completing a rotation once every four days compared with every four weeks for the sun......... Posted by: Sean      Read more         Source

May 18, 2008, 10:13 PM CT

Dusty Galaxies

Anyone gazing up on a dark clear night is greeted by the spectacle of thousands of powerful fusion reactors - the stars. These balls of extremely hot gas are generating unimaginably large quantities of energy. Even the stars within a cube of "only" one light year on a side, taken at a random position in the universe, generate on average 40 quadrillion kilowatthours in one year. This would be enough to meet the current energy consumption needs of mankind 300 times over. Even so, it now appears that from our vantage point we are only registering about half the total energy released by stars in our part of the universe; the other half is being absorbed by miniscule particles of dust floating in the vast expanses of interstellar space within galaxies. This is the conclusion reached by a team of astrophysicists from institutes around the world, including the Max Planck Institute for Nuclear Physics in Heidelberg. The results have implications for our understanding of the creation and evolution of galaxies through cosmic history (The Astrophysical Journal, 10 May 2008).

Galaxies are gigantic systems containing billions of stars bound together by gravity.

Our sun is one of around 200 billion stars in the Milky Way, which is a typical example of one such system. If we could view the Milky Way from the outside, the combined light from the stars would appear like a giant Catherine wheel. Since almost all stars are located within galaxies, and since in any case stars become too faint to be detected individually if they are too far away, the total light emitted by galaxies has to be investigated in order to measure the total energy output from stars in the universe......... Posted by: Sean      Read more         Source

May 18, 2008, 10:01 PM CT

Laser May Aid Searches for Earthlike Planets

Researchers at the University of Konstanz (Gera number of) and the National Institute of Standards and Technology (NIST) have demonstrated an ultrafast laser that offers a record combination of high speed, short pulses and high average power. The new laser is expected to have a range of applications from gas sensors to communications, but in particular, say researchers, it could boost the sensitivity of astronomical tools searching for other Earthlike planets as much as 100 fold.

The dime-sized laser, described last week at the Conference on Lasers and Electro-Optics,* emits 10 billion pulses per second, each lasting about 40 femtoseconds (quadrillionths of a second). The short, fast pulses make it ideal for use as a "frequency comb"-an ultraprecise technique for measuring frequencies of light. It is 10 times faster than a standard NIST frequency comb, produces much shorter pulses than comparable lasers, and is 100 to 1000 times more powerful than typical high-speed lasers, producing clearer signals in experiments. It was built by Albrecht Bartels at the Center for Applied Photonics of the University of Konstanz in Gera number of.

As a frequency comb the laser could sharpen the search for planets orbiting distant stars. Astronomers look for slight variations in the apparent colors of starlight over time that are caused by the star wobbling from the gravitational pull of an orbiting planet. The effect is very subtle, and astronomers are limited by the frequency standards they use to calibrate their instruments. Frequency combs could be such superior calibration tools that they would make it possible to detect even tiny Earthlike planets that cause color shifts equivalent to a star wobble of just a few centimeters per second. Current instruments can detect-at best-a wobble of about 1 meter per second......... Posted by: Sean      Read more         Source

May 15, 2008, 8:29 PM CT

'Super Road Maps' of Planets and Moons

Technology that could someday "MapQuest" Mars and other bodies in the solar system is under development at Rochester Institute of Technology's Rochester Imaging Detector Laboratory (RIDL), in collaboration with Massachusetts Institute of Technology's Lincoln Laboratory.

Three-Dimensional "super roadmaps" of other planets and moons would provide robots, astronauts and engineers details about atmospheric composition, biohazards, wind speed and temperature. Information like this could help land future spacecraft and more effectively navigate roving cameras across a Martian or lunar terrain.

RIT scientist Donald Figer and his team are in the process of developing a new type of detector that uses LIDAR (LIght Detection and Ranging), a technique similar to radar, but which uses light instead of radio waves to measure distances. The project will deliver a new generation of optical/ultraviolet imaging LIDAR detectors that will significantly extend NASA science capabilities for planetary applications by providing 3-D location information for planetary surfaces and a wider range of coverage than the single-pixel detectors currently combined with LIDAR.

The device will consist of a 2-D continuous array of light sensing elements connected to high-speed circuits. The $547,000 NASA-funded program also includes a potential $589,000 phase for fabrication and testing......... Posted by: Sean      Read more         Source

May 14, 2008, 9:00 PM CT

Discovery of most recent supernova in our galaxy

The most recent supernova in our Galaxy has been discovered by tracking the rapid expansion of its remains. This result, using NASA's Chandra X-ray Observatory and NRAO's Very Large Array (VLA), has implications for understanding how often supernovas explode in the Milky Way galaxy.

The supernova explosion occurred about 140 years ago, making it the most recent supernova in the Milky Way as measured in Earth's time frame. Previously, the last known galactic supernova occurred around 1680, based on studying the expansion of its remnant Cassiopeia A.

The recent supernova explosion was not seen in optical light about 140 years ago because it occurred close to the center of the Galaxy, and is embedded in a dense field of gas and dust. This made it about a trillion times fainter, in optical light, than an unobscured supernova. However, the supernova remnant it caused, G1.9+0.3, is now seen in X-ray and radio images.

"We can see some supernova explosions with optical telescopes across half of the Universe, but when they're in this murk we can miss them in our own cosmic backyard," said Stephen Reynolds of North Carolina State University, who led the Chandra study. "Fortunately, the expanding gas cloud from the explosion shines brightly in radio waves and X-rays for thousands of years. X-ray and radio telescopes can see through all that obscuration and show us what we've been missing"......... Posted by: Sean      Read more         Source

May 13, 2008, 7:43 PM CT

$34 Million For U.S. Environmental Satellite

A $34 million solar instrument package to be built by the University of Colorado at Boulder, considered a crucial tool to help monitor global climate change, has been restored to a U.S. government satellite mission slated for launch in 2013.

The package will be built by CU-Boulder's Laboratory for Atmospheric and Space Physics for the first flight of the National Polar Orbiting Operational Environmental Satellite System, or NPOESS. The instrument package had been canceled during the 2006 restructuring of the NPOESS program, a joint venture of the National Oceanic and Atmospheric Administration, NASA and the Air Force.

Known as the Total Solar Irradiance Sensor, or TSIS, the CU-Boulder package will fly on the first flight of NPOESS in 2013 and is anticipated to fly on two subsequent NPOESS missions slated for 2015 and 2020. The two latter NPOESS missions are expected to bring in an additional $30 million to CU-Boulder, said LASP Senior Researcher and TSIS Project Manager Tom Sparn.

TSIS consists of two instruments, including the Total Irradiance Monitor, or TIM, which measures the total light coming from the sun at all wavelengths, "a fundamental quantity for determining the energy balance of the planet," said TSIS principal investigator Peter Pilewskie of LASP......... Posted by: Sean      Read more         Source

May 7, 2008, 7:00 PM CT

New Type of Pulsating White Dwarf Star

University of Texas at Austin astronomers Michael H. Montgomery and Kurtis A. Williams, along with graduate student Steven DeGennaro, have predicted and confirmed the existence of a new type of variable star, with the help of the 2.1-meter Otto Struve Telescope at McDonald Observatory. The discovery is announced in today's issue of Astrophysical Journal Letters.

This research was funded by the National Science Foundation and the Delaware Asteroseismic Research Center.

Called a "pulsating carbon white dwarf," this is the first new class of variable white dwarf star discovered in more than 25 years. Because the overwhelming majority of stars in the universe--including the sun--will end their lives as white dwarfs, studying the pulsations (i.e., variations in light output) of these newly discovered examples gives astronomers a window on an important end point in the lives of most stars.

A white dwarf star is the leftover remnant of a sun-like star that has burned all of the nuclear fuel in its core. It is extremely dense, packing half to 1.5 times the sun's mass into a volume about the size of Earth. Until recently, there were believed to be two main types of white dwarfs: those with an outer layer of hydrogen (about 80 percent of white dwarfs), and those with an outer layer of helium, whose hydrogen shells have somehow been stripped away (the other 20 percent)......... Posted by: Sean      Read more         Source

May 5, 2008, 6:57 PM CT

65-million-year-old asteroid impact

The asteroid presumed to have wiped out the dinosaurs struck the Earth with such force that carbon deep in the Earth's crust liquefied, rocketed skyward, and formed tiny airborne beads that blanketed the planet, say researchers from the U.S., U.K., Italy, and New Zealand in this month's Geology.

The beads, known to geologists as carbon cenospheres, cannot be formed through the combustion of plant matter, contradicting a hypothesis that the cenospheres are the charred remains of an Earth on fire. If confirmed, the discovery suggests environmental circumstances accompanying the 65-million-year-old extinction event were slightly less dramatic than previously thought.

"Carbon embedded in the rocks was vaporized by the impact, eventually forming new carbon structures in the atmosphere," said Indiana University Bloomington geologist Simon Brassell, study coauthor and former adviser to the paper's lead author, Mark Harvey.

The carbon cenospheres were deposited 65 million years ago next to a thin layer of the element iridium -- an element more likely to be found in Solar System asteroids than in the Earth's crust. The iridium-laden dust is thought to bethe shattered remains of the 200-km-wide asteroid's impact. Like the iridium layer, the carbon cenospheres are apparently common. They've been found in Canada, Spain, Denmark and New Zealand......... Posted by: Sean      Read more         Source

April 30, 2008, 6:46 PM CT

Catching a Glimpse of a Black Hole's Fury

Using the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and a host of international telescope partners, a team of scientists has made the clearest observation yet of innermost region of a black hole.

From the observations, astronomers found good evidence that the enormous jets of particles emitted by supermassive black holes are corkscrewed in a way predicted by theory. The scientists believe the coiling is a result of twisted magnetic fields acting on the particle streams.

The scientists reported their findings in the April 24 issue of Nature

Led by Alan Marscher of Boston University, the international team of scientists studied the galaxy BL Lacertae located 950 million light years from Earth. By observing an outburst from the galaxy from late 2005 to 2006, the team observed bursts of photons oriented in a way predicted by theories about the twisted magnetic fields of black holes.

The VLBA is part of NSF's National Radio Astronomy Observatory (NRAO). A more detailed release--including graphics and a broadcast-quality animation--is available from NRAO at: http://www.nrao.edu/pr/2008/bllac.

Additional images, explanations, data sets and even a related song are available at a Web site posted by Marscher: http://www.bu.edu/blazars/BLLac.html........ Posted by: Sean      Read more         Source

April 30, 2008, 6:10 PM CT

Stellar Ticking Time Bomb Explodes on Cue

Using observations from NASA's Rossi X-ray Timing Explorer (RXTE), an international team of astronomers has discovered a timing mechanism that allows them to predict exactly when a superdense star will unleash incredibly powerful explosions.

"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," says lead author Diego Altamirano of the University of Amsterdam in the Netherlands.

The bursts occur on a neutron star, which is the collapsed remnant of a massive star that exploded in a supernova. The neutron star belongs to a binary system that can be described as a ticking time bomb. Hydrogen and helium gas from a companion star spirals onto the neutron star, slowly accumulating on its surface until it heats up to a critical temperature. Suddenly, the hydrogen and helium begin to fuse uncontrollably into heavier elements, igniting a thermonuclear flame that quickly spreads around the entire star. The resulting explosion appears as a bright flash of X-rays.

These bursts, which can occur several times per day from the same neutron star, release more energy in just 10 to 100 seconds than our sun radiates in an entire week. Put another way, the energy is equivalent to 100 fifteen-megaton hydrogen bombs exploding simultaneously over each postage-stamp-size patch of the neutron star's surface......... Posted by: Sean      Read more         Source

April 24, 2008, 10:19 PM CT

Plethora Of Interacting Galaxies

Galaxy collisions produce a remarkable variety of intricate structures, as 59 new images from the NASA/ESA Hubble space telescope show.

Interacting galaxies are found throughout the Universe, sometimes dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that form new galaxies.

A series of 59 new images of colliding galaxies, the largest collection ever published simultaneously, has been released from archived raw Hubble images to mark the 18th anniversary of the telescope's launch.

Galaxy mergers, which were more common in the early Universe than they are today, are believed to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths.

Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.

For the entire collection of 59 images, please see this article on the European Hubble homepage......... Posted by: Sean      Read more         Source

April 13, 2008, 9:10 PM CT

Size and Frequency of Meteorite Impacts

Researchers have developed a new way of determining the size and frequency of meteorites that have collided with Earth.

Their work shows that the size of the meteorite that likely plummeted to Earth at the time of the Cretaceous-Tertiary (K-T) boundary 65 million years ago was four to six kilometers in diameter. The meteorite was the trigger, researchers believe, for the mass extinction of dinosaurs and other life forms.

François Paquay, a geologist at the University of Hawaii at Manoa (UHM), used variations (isotopes) of the rare element osmium in sediments at the ocean bottom to estimate the size of these meteorites. The results are published in this week's issue of the journal Science.

When meteorites collide with Earth, they carry a different osmium isotope ratio than the levels normally seen throughout the oceans.

"The vaporization of meteorites carries a pulse of this rare element into the area where they landed," says Rodey Batiza of the National Science Foundation (NSF)'s Division of Ocean Sciences, which funded the research along with NSF's Division of Earth Sciences. "The osmium mixes throughout the ocean quickly. Records of these impact-induced changes in ocean chemistry are then preserved in deep-sea sediments."

Paquay analyzed samples from two sites, Ocean Drilling Program (ODP) site 1219 (located in the Equatorial Pacific), and ODP site 1090 (located off of the tip of South Africa) and measured osmium isotope levels during the late Eocene period, a time during which large meteorite impacts are known to have occurred......... Posted by: Sean      Read more         Source

April 9, 2008, 10:02 PM CT

Rocket Mystery Explained With New Imaging Technique

There's a strange wave phenomenon that's plagued rocket researchers for years, a lurking threat with the power to destroy an engine at almost any time. For decades, researchers have had a limited understanding of how or why it happens because they could not replicate or investigate the problem under controlled laboratory conditions.

Researchers generally think that these powerful and unstable sound waves, created by energy supplied by the combustion process, were the cause of rocket failures in several U.S. and Russian rockets. Researchers have also observed these mysterious oscillations in other propulsion and power-generating systems such as missiles and gas turbines.

Now, scientists at the Georgia Institute of Technology have developed a liquid rocket engine simulator and imaging techniques that can help demystify the cause of these explosive sound waves and bring researchers a little closer to being able to understand and prevent them. The Georgia Tech research team was able to clearly demonstrate that the phenomenon manifests itself in the form of spinning acoustic waves that gain destructive power as they rotate around the rocket's combustion chamber.

"This is a very troublesome phenomenon in rockets," said Ben Zinn, the David S. Lewis Jr. Chair and Regents' Professor in the Guggenheim School of Aerospace Engineering at Georgia Tech. "These spinning acoustic oscillations destroy engines without anyone fully understanding how these waves are formed. Visualizing this phenomenon brings us a step closer to understanding it."........ Posted by: Sean      Read more         Source