17
Dec 10

NASA Discovers Asteroid Delivered Assortment of Meteorites

Source: NASA


Image credit: Andreus / Dreamstime.com.

An international team of scientists studying remnants of an asteroid that crashed into the Nubian Desert in October 2008 discovered it contained at least 10 different types of meteorites. Some of them contained chemicals that form the building blocks of life on Earth, and those chemicals were spread through all parts of the asteroid by collisions.

Chemists at Stanford University found that different meteorite types share the same distinct fingerprint of polycyclic aromatic hydrocarbons (PAHs). These complex organic molecules are distributed throughout the galaxy and form on Earth from incomplete combustion.

A research team from NASA's Goddard Space Flight Center in Greenbelt, Md., found amino acids in strongly heated fragments of the asteroid, where all such molecules should have been destroyed. Both PAHs and amino acids are considered building blocks of life.

Before landing on Earth, the 13-foot asteroid was detected by a telescope from the NASA-sponsored Catalina Sky Survey based at the University of Arizona in Tucson. Hours prior to its demise, astronomers and scientists around the world tracked and scanned the asteroid. It was the first time a celestial object was observed prior to entering Earth's atmosphere.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., created a search grid and impact target area. The data helped Peter Jenniskens, an astronomer at NASA's Ames Research Center in Moffett Field, Calif., and the SETI Institute of Mountain View, Calif., guide a recovery team from the University of Khartoum in Sudan to search the desert landscape. During four expeditions, approximately 150 students recovered nearly 600 meteorite fragments weighing a total of more than 23 pounds.

"Right from the start, the students were surprised to find so much diversity in meteorite texture and hue," said Muawia Shaddad, an astronomer at the University of Khartoum, who led the search effort. "We estimate the asteroid initially weighed about 59 tons, of which about 86 pounds survived the explosion high in the atmosphere."

Subsequently, scientists determined most of the fragments are a rare type of meteorite called ureilites. Less than 10 of the nearly 1,000 known meteorites are ureilites. The recovery team made history when they found the first-ever freshly fallen mixed-composition, or polymict ureilite. The majority of the remaining fragments are similar to the more common types of meteorites called chondrites.

Other Ames researchers showed the ureilite fragments contained widely varying amounts of the minerals called olivine and pyroxene. Carnegie Institute of Washington researchers found these minerals have the full range of oxygen atom signatures detected in previous ureilites. Scientists believe this is evidence all ureilites originated from the same source, called the ureilite parent body. Astronomers theorize the parent body experienced a giant collision approximately 4.5 billion years ago and caused iron-rich minerals to smelt into metallic iron. However, the olivine and pyroxene didn't melt, which allowed the oxygen atoms in them to stay in the same arrangement as when they first formed.

Researchers at NASA's Johnson Space Center in Houston were able to deduce that much of the ureilite parent body was reduced to fragments measuring 30 to 300 feet during this giant collision. After the catastrophic collision, scientists believe the material that ended up making 2008 TC3 had a long history of violent collisions and impacts. These later collisions ground the fragments down into the smaller sand grain-sized pieces that gathered loosely together with many voids.

Researchers believe the amino acids were delivered to 2008 TC3 during the later impacts, or formed directly from trapped gases as the asteroid cooled following the giant collision. Other non-ureilite types of meteorites also became part of the asteroid. To date, ten different meteorite types have been identified, accounting for 20-30 percent of the asteroid's recovered remains.

"Asteroids have just become a lot more interesting," Jenniskens said. "We were surprised to find that not all of the meteorites we recovered were the same, even though we are certain they came from the same asteroid."

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17
Dec 10

Space Telescope European coordinating facility closes after 26 successful years

Source: ESA/Hubble Space Telescope

The Space Telescope European Coordinating Facility, a unique collaboration between the European Space Agency (ESA) and the European Southern Observatory, will close on 31 December 2010 after 26 years. ESA’s continuing partnership with NASA on the Hubble mission ensures that European astronomers will continue to have access to observing time.

The Space Telescope European Coordinating Facility (ST-ECF), the scientific and technical co-ordination centre for the Hubble Space Telescope in Europe, will close its doors at the end of December 2010. This is part of a process in which the European Space Agency is streamlining its operations and concentrating astronomical operations, archiving and data reduction expertise at its European Space Astronomy Centre (ESAC) in Spain.

The ST-ECF was formed in 1984, six years before Hubble’s launch, as a key plank in ESA’s partnership with NASA and as a vital element in maximising Europe’s scientific return in the pre-internet age. Rather than simply contribute to Hubble science and technology programmes in the US, ESA made the strategic decision to build capabilities in Europe. As a result, the ST-ECF was formed as a joint venture between ESA and the European Southern Observatory (ESO), combining the technical and scientific expertise of both organisations.

The ST-ECF’s primary function has been as a support facility, both by contributing to the Hubble project and providing expertise and advice to European astronomers using Hubble. But this work has also had knock-on benefits elsewhere. ESO Director General, Tim de Zeeuw explains: “Establishing the ST-ECF within ESO allowed a very productive cross-fertilisation of ideas to take place. For example, the ST-ECF’s work on software, imaging and data archives have fed back into NASA’s work on Hubble. Conversely, the experience of being involved in Hubble gave ESO invaluable expertise for our Very Large Telescope.”

One area where the ST-ECF has made a particular impact is in astronomical image processing. In the early days, techniques were developed to counteract the effects of Hubble’s flawed mirror (deconvolution). This work subsequently evolved, in collaboration with NASA’s Space Telescope Science Institute (STScI), to use a combination of multiple, slightly displaced exposures (dithering) with a combination technique (drizzling) to greatly improve the imaging capability of the telescope. This work has proved very productive for astronomy in general, not just for Hubble.

In addition, staff at the ST-ECF made important advances in the modelling of the performance of various astronomical instruments. This theoretical knowledge lets astronomers create highly sophisticated computer simulations of the instruments, allowing for precise calibration of observations and more accurate results. This modelling work has provided substantial improvements in the scientific data produced by Hubble over the years.

The ST-ECF was also a pioneer of the early internet. Communication and co-ordination with NASA in the US and sharing data with astronomers across Europe meant that effective computer networking was key. To this end, the facility pioneered online access to scientific data archives, and set up one of the very first websites in Europe in the summer of 1993.

In the last few years, the ST-ECF has developed sophisticated software to exploit a capability that enables Hubble’s cameras to be used for the simultaneous spectroscopy of many sources in the field of view. Applied from a telescope in space this slitless spectroscopy is an enormously powerful technique to study the motions and properties of objects that are so faint that they cannot be reached in any other way.

A separate and very important contribution of the ST-ECF to the ESA Science Programme over many years has been its responsibility for developing communications and outreach in Europe for Hubble.

While the ST-ECF’s closure marks the end for one aspect of Hubble activities in Europe, ESA remains a firm partner to NASA in the space telescope’s continuing mission. To this end, ESA’s Science Programme Committee recently voted unanimously to extend the ESA contribution to the end of 2014, with a further extension possible.

Martin Kessler, head of ESA’s science operations department said: “European astronomers will have access to ESA’s share of observing time for as long as Hubble remains in the sky. Additionally, we expect to preserve access to Hubble data via the European Space Astronomy Centre. As part of the ongoing collaboration with NASA, ESA will continue to deploy staff based at the Space Telescope Science Institute in Baltimore, USA.”

ESO will continue to support the ESA public outreach effort for Hubble, processing images for public release, running the ESA/Hubble website at www.spacetelescope.org and producing the popular Hubblecast podcast series.

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17
Dec 10

Zooniverse lauches PlanetHunters project

Source: Planet Hunters


Screenshot of Planet Hunters website

Ever dreamed of being the first to make a discovery? Want to find a planet of your own? Thanks to http://www.planethunters.org, the latest Zooniverse project, you might just be able to, using data from NASA's Kepler mission. Kepler's goal is to catch the slight dip in brightness that's caused by a planet passing in front of its parent star.

NASA's Kepler spacecraft is one of the most powerful tools in the hunt for extrasolar planets. The Kepler Team computers are sifting through the data, but we at Planet Hunters are betting that there will be planets which can only be found via the remarkable human ability for pattern recognition.

The Kepler Team computers are sifting through the data, but we at Planet Hunters are betting that there will be planets which can only be found via the remarkable human ability for pattern recognition. This is a gamble, a bet, if you will, on the ability of humans to beat machines just occasionally - and for us to have a chance we need your help. Fancy giving it a try? If you do, you could be the first to spot an new planet – it may be a Jupiter-size behemoth or even an Earth-sized rock.  (go to PlanetHunters Project)

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17
Dec 10

Building Blocks of Life Created in "Impossible" Place

Source: NASA


Hubble Space Telescope picture of what was first thought to be a comet but is probably an asteroid collision.

NASA-funded scientists have discovered amino acids, a fundamental building block of life, in a meteorite where none were expected.

"This meteorite formed when two asteroids collided," said Dr. Daniel Glavin of NASA’s Goddard Space Flight Center, Greenbelt, Md. "The shock of the collision heated it to more than 2,000 degrees Fahrenheit, hot enough that all complex organic molecules like amino acids should have been destroyed, but we found them anyway." Glavin is lead author of a paper on this discovery appearing December 15 in Meteoritics and Planetary Science. "Finding them in this type of meteorite suggests that there is more than one way to make amino acids in space, which increases the chance for finding life elsewhere in the Universe."

Amino acids are used to make proteins, the workhorse molecules of life, used in everything from structures like hair to enzymes, the catalysts that speed up or regulate chemical reactions. Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acids in a huge variety of arrangements to build millions of different proteins. Previously, scientists at the Goddard Astrobiology Analytical Laboratory have found amino acids in samples of comet Wild 2 from NASA’s Stardust mission, and in various carbon-rich meteorites. Finding amino acids in these objects supports the theory that the origin of life got a boost from space - some of life’s ingredients formed in space and were delivered to Earth long ago by meteorite impacts.

When Dr. Peter Jenniskens of the SETI Institute, Mountain View, Calif., and NASA's Ames Research Center, Moffett Field, Calif., approached NASA with the suggestion to search for amino acids in the carbon-rich remnants of asteroid 2008 TC3, expectations were that nothing was to be found. Because of an unusually violent collision in the past, this asteroid's ingredients for life were a "culinary disaster" and now mostly in the form of graphite. The small asteroid, estimated at six to fifteen feet across, was the first to be detected in space prior to impact on Earth on October 7, 2008. When Jenniskens and Dr. Muawia Shaddad of the University of Khartoum recovered remnants in the Nubian Desert of northern Sudan, the remnants turned out to be the first Ureilite meteorites found in pristine condition.

A meteorite sample was divided between the Goddard lab and a lab at the Scripps Institution of Oceanography at the University of California, San Diego. "Our analyses confirm those obtained at Goddard," said Professor Jeffrey Bada of Scripps, who led the analysis there. The extremely sensitive equipment in both labs detected small amounts of 19 different amino acids in the sample, ranging from 0.5 to 149 parts per billion. The team had to be sure that the amino acids in the meteorite didn’t come from contamination by life on Earth, and they were able to do so because of the way amino acids are made. Amino acid molecules can be built in two ways that are mirror images of each other, like your hands. Life on Earth uses left-handed amino acids, and they are never mixed with right-handed ones, but the amino acids found in the meteorite had equal amounts of the left and right-handed varieties. (read more)

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