July 27, 2009, 11:10 PM CT

Rare 'Green Pea' galaxies

A team of astronomers has discovered a group of rare galaxies called the "Green Peas" with the help of citizen researchers working through an online project called Galaxy Zoo. The finding could lend unique insights into how galaxies form stars in the early universe.

The Galaxy Zoo users, who volunteer their spare time to help classify galaxies in an online image bank, came across many objects that stuck out because of their small size and bright green color. They dubbed them the Green Peas.

Employing the help of the volunteers to further analyze these strange new objects, the astronomers discovered that the Green Peas are small, compact galaxies forming stars at an incredibly high rate.

"These are among the most extremely active star-forming galaxies we've ever found," said Carolin Cardamone, an astronomy graduate student at Yale and main author of the paper, to be published in an upcoming issue of the Monthly Notices of the Royal Astronomical Society..

Of the one million galaxies that make up Galaxy Zoo's image bank, the team found only 250 Green Peas. "No one person could have done this on their own," Cardamone said. "Even if we had managed to look through 10,000 of these images, we would have only come across a few Green Peas and wouldn't have recognized them as a unique class of galaxies"......... Posted by: Sean      Read more         Source

July 21, 2009, 10:33 PM CT

Jupiter pummeled, leaving a bruise

Something slammed into Jupiter in the last few days, creating a dark bruise about the size of the Pacific Ocean.

The bruise was noticed by an amateur astronomer on Sunday, July 19. University of California, Berkeley, astronomer Paul Kalas took advantage of previously scheduled observing time on the Keck II telescope in Hawaii to image the blemish in the early morning hours of Monday, July 20. The near infrared image showed a bright spot in Jupiter's southern hemisphere, where the impact had propelled reflective particles high into the relatively clear stratosphere.

In visible light, the bruise appears dark against the bright surface of Jupiter.

The observation made with the Keck II telescope marks only the second time astronomers have seen the results of an impact on the planet. The first collision occurred exactly 15 years ago, between July 16 and 22, 1994, when more than 20 fragments of comet Shoemaker-Levy 9 collided with Jupiter.

The Shoemaker-Levy 9 (SL9) impact events were well-studied by astronomers, including several from UC Berkeley, and a number of theories were subsequently developed based on the observations.

"Now we have a chance to test these ideas on a brand new impact event," said Kalas, who observed the aftermath of the new impact with the help of Michael Fitzgerald of Lawrence Livermore National Lab and UCLA......... Posted by: Sean      Read more         Source

July 4, 2009, 10:55 PM CT

LRO's First Moon Images

NASA's Lunar Reconnaissance Orbiter has transmitted its first images since reaching the moon on June 23. The spacecraft's two cameras, collectively known as the Lunar Reconnaissance Orbiter Camera, or LROC, were activated June 30. The cameras are working well and have returned images of a region in the lunar highlands south of Mare Nubium (Sea of Clouds).

As the moon rotates beneath LRO, LROC gradually will build up photographic maps of the lunar surface.

"Our first images were taken along the moon's terminator -- the dividing line between day and night -- making us initially unsure of how they would turn out," said LROC Principal Investigator Mark Robinson of Arizona State University in Tempe. "Because of the deep shadowing, subtle topography is exaggerated, suggesting a craggy and inhospitable surface. In reality, the area is similar to the region where the Apollo 16 astronauts safely explored in 1972. While these are magnificent in their own right, the main message is that LROC is nearly ready to begin its mission".

"Our first images were taken along the moon's terminator -- the dividing line between day and night -- making us initially unsure of how they would turn out," said LROC Principal Investigator Mark Robinson of Arizona State University in Tempe. "Because of the deep shadowing, subtle topography is exaggerated, suggesting a craggy and inhospitable surface. In reality, the area is similar to the region where the Apollo 16 astronauts safely explored in 1972. While these are magnificent in their own right, the main message is that LROC is nearly ready to begin its mission."........ Posted by: Sean      Read more         Source

July 2, 2009, 10:08 PM CT

New focus on the moon

NASA's Lunar Reconnaissance Orbiter Camera (LROC) has taken and received its first images of the Moon, kicking off the year-long mapping mission of Earth's nearest celestial neighbor. The LROC imaging system, under the watchful eyes of Arizona State University professor Mark Robison, the principal investigator, consists of two Narrow Angle Cameras (NACs) to provide high-resolution black-and-white images, a Wide Angle Camera (WAC) to provide images in seven color bands over a 60-kilometer (37.28-mile) swath, and a Sequence and Compressor System (SCS) supporting data acquisition for both cameras.

NASA reports that the Lunar Reconnaissance Orbiter, which launched June 18, is performing exceptionally well and spacecraft checkout is proceeding smoothly, so smoothly in fact that LROC was given an early, but short (two orbits) opportunity Tuesday evening to measure temperatures and background values while imaging. Since LRO is in a terminator orbit, much of the area photographed was in shadows, which is actually a good situation for performing engineering checks of camera settings, as per Robinson, with ASU's School of Earth and Space Exploration. Much to the delight of the LROC team, a few of the images captured dramatic views of the surface.

"Our first images were taken along the Moon's terminator the dividing line between day and night making us initially unsure of how they would turn out," says Robinson. "Because of the deep shadowing, subtle topography is exaggerated suggesting a craggy and inhospitable surface. In reality, the area is similar to the region where the Apollo 16 astronauts comfortably explored in 1972. Though these images are magnificent in their own right, the main message is that LROC is nearly ready to begin its mission"......... Posted by: Sean      Read more         Source

June 16, 2009, 5:11 AM CT

Meteorite grains divulge Earth's cosmic roots

The interstellar stuff that became incorporated into the planets and life on Earth has younger cosmic roots than theories predict, as per the University of Chicago postdoctoral scholar Philipp Heck and his international team.

of colleagues.

Heck and colleagues examined 22 interstellar grains from the Murchison meteorite for their analysis. Dying sun-like stars flung the Murchison grains into space more than 4.5.

billion years ago, before the birth of the solar system. Researchers know the grains formed outside the solar system.

because of their exotic composition.

"The concentration of neon, produced during cosmic-ray irradiation, allows us to determine the time a grain has spent in interstellar space," Heck said. His team determined that 17 of the grains spent somewhere between three million and 200 million years in interstellar space, far less than the theoretical estimates of approximately 500 million years. Only.

three grains met interstellar duration expectations (two grains yielded no reliable age).

"The knowledge of this lifetime is essential for an improved understanding of interstellar processes, and to better contain the timing of formation processes of the solar system," Heck.

said. A period of intense star formation that preceded the sun's birth may have produced large quantities of dust, thus accounting for the timing discrepancy, as per the......... Posted by: Sean      Read more         Source

June 10, 2009, 9:37 PM CT

Planet-forming disk orbiting twin suns

Astronomers are announcing today that a sequence of images collected with the Smithsonian's Submillimeter Array (SMA) clearly reveals the presence of a rotating molecular disk orbiting the young binary star system V4046 Sagittarii. The SMA images provide an uncommonly vivid snapshot of the process of formation of giant planets, comets, and Pluto-like bodies. The results also confirm that such objects may just as easily form around double stars as around single stars like our Sun.

These findings are being presented by UCLA graduate student David Rodriguez in a press conference at the American Astronomical Society meeting in Pasadena, Calif.

"It's a case of seeing is believing," says Joel Kastner of the Rochester (NY) Institute of Technology, the lead scientist on the study. "We had the first evidence for this rotating disk in radio telescope observations of V4046 Sagittarii that we made last summer. But at that point, all we had were molecular spectra, and there are different ways to interpret the spectra. Once we saw the image data from the SMA, there was no doubt that we have a rotating disk here".

Co-author David Wilner of the Harvard-Smithsonian Center for Astrophysics (CfA) adds, "This is good evidence that planets can form around binary stars, which expands the number of places we can look for extrasolar planets. Somewhere in our galaxy, an alien world may enjoy double sunrises and double sunsets"......... Posted by: Sean      Read more         Source

May 22, 2009, 5:23 AM CT

Victoria Crater unveils more of Mars' geologic past

After thoroughly investigating Victoria Crater on Mars for two years, the instruments aboard the Rover Opportunity reveal more evidence of our neighboring red planet's windy, wet and wild past. The overview of the findings compiled in one source is reported in the latest issue of the journal Science (May 22, 2009).

Opportunity's two-year exploration of Victoria Crater a half-mile wide and 250 feet deep yielded a treasury of information about the planet's geologic history and supported prior findings indicating that water once flowed on the planet's surface, as per Steve Squyres, Cornell professor of astronomy and the principal investigator for NASA's Mars Exploration Rover mission. The rover is now heading south toward Endeavor crater, 8.5 miles away.

A number of of those observations of hematite spheres ("blueberries"), sulfate-rich sandstone and small chunks of rock containing kamacite, troilite and other minerals usually found in meteorites are consistent with Opportunity's findings across Meridiani Planum. "It shows that the processes that we investigated in detail for the first time at Endurance crater [where Opportunity spent six months in 2004] are regional in scale, [indicating that] the kinds of conclusions that we first reached at Endurance apply perhaps across Meridiani," said Squyres......... Posted by: Sean      Read more         Source

May 7, 2009, 10:10 PM CT

Hubble repair mission carrying $70 million instrument

A $70 million instrument designed by the University of Colorado at Boulder to probe the evolution of galaxies, stars and intergalactic matter from its perch on the orbiting Hubble Space Telescope is on schedule for its slated May 11 launch from Kennedy Space Center in Florida aboard NASA's space shuttle Atlantis.

Originally scheduled for launch in 2004, NASA's Hubble Servicing mission has been beset by delays over the years by causes ranging from the Columbia space shuttle accident to mechanical glitches. But CU-Boulder Professor James Green of the Center for Astrophysics and Space Astronomy, principal investigator for $70 million Cosmic Origin Spectrograph, or COS, said from the Kennedy Space Center today things look very good for the launch of Atlantis next Monday at 2:01 p.m. EDT.

""There have been no hiccups this time around and everything is going very smoothly," said Green. We are right on schedule and the team is optimistic about the launch."

The telephone-booth-sized COS, built primarily by CU-Boulder's industrial partner, Ball Aerospace & Technology Corp. of Boulder, should help researchers better understand the "cosmic web" of material believed to permeate the universe, said Green. COS will gather information from ultraviolet light emanating from distant objects, allowing researchers to look back several billion years and reconstruct the physical conditions and evolution of the early universe......... Posted by: Sean      Read more         Source

April 29, 2009, 5:19 AM CT

We Owe It All to Comets

Comets have always fascinated us. A mysterious appearance could symbolize God's displeasure or mean a sure failure in battle, at least for one side. Now Tel Aviv University justifies our fascination - comets might have provided the elements for the emergence of life on our planet.

While investigating the chemical make-up of comets, Prof. Akiva Bar-Nun of the Department of Geophysics and Planetary Sciences at Tel Aviv University found they were the source of missing ingredients needed for life in Earth's ancient primordial soup. "When comets slammed into the Earth through the atmosphere about four billion years ago, they delivered a payload of organic materials to the young Earth, adding materials that combined with Earth's own large reservoir of organics and led to the emergence of life," says Prof. Bar-Nun.

It was the chemical composition of comets, Prof. Bar-Nun believes, that allowed them to kickstart life. He has published his theory widely in scientific journals, including the journal Icarus.



A Pinch of Argon, A Dash of Xenon

Using a one-of-a-kind machine built at Tel Aviv University, scientists were able to simulate comet ice, and observed that comets contain ingredients necessary for providing the basic nutrients of life......... Posted by: Sean      Read more         Source

April 23, 2009, 5:25 AM CT

Fermi Active Galaxies Ready for Their Close-Up

An international team of astronomers has used the world's biggest radio telescope to look deep into the brightest galaxies that NASA's Fermi Gamma-ray Space Telescope can see. The study solidifies the link between an active galaxy's gamma-ray emissions and its powerful radio-emitting jets.

"Now we know for sure that the fastest, most compact, and brightest jets we see with radio telescopes are the ones that are able to kick light up to the highest energies," said Yuri Kovalev, a team member at the Max Planck Institute for Radio Astronomy in Bonn, Gera number of.

The brightest galaxies Fermi sees are active galaxies, which emit oppositely directed jets of particles traveling near the speed of light. Some, called blazars, are particularly bright because one of the jets happens to be directed toward us. Astronomers think that these jets somehow arise as a consequence of matter falling into a massive black hole at the galaxy's center, but the process is not well understood.

To peer into the jets, Kovalev and colleagues used the National Science Foundation's Very Long Baseline Array (VLBA), a set of ten radio telescopes located from Hawaii to St. Croix in the U.S. Virgin Islands and operated by the National Radio Astronomy Observatory. When the signals from these telescopes are combined, the array acts like a single enormous radio dish more than 5,300 miles across. The VLBA can resolve details about a million times smaller than Fermi can and 50 times smaller than any optical telescope......... Posted by: Sean      Read more         Source