| 
News
Spotlight on GCA Video
Congratulations to Dr. Michael Mumma who receives the 2010 NASA
Exceptional Scientific Achievement Award:
"In recognition of the first definitive detection of methane in the
atmosphere of Mars, revealing an active and dynamic planet and a
possible abode for life beyond Earth."
|
|
|
|
 |
Organic Chemistry on Cosmic Ice (3.4.2013)
GCA scientists, Reggie Hudson and Perry Gerakines, have been studying the ultracool chemistry of cosmic ice in GSFC's Cosmic Ice Laboratory. Cosmic ice in deep space is amorphous (unstructured), unlike the ice crystals on Earth. It is so widespread in interstellar space that it could be the most common form of water in the Universe. Often particles and organic compounds are trapped in this ice that could provide clues to life in the Universe. The scientists created ices spiked with an amorphous form of an amino acid (either glycine, alanine or phenylalanine) that is found in proteins, then bombarded the samples with a high-energy proton beam. They found that the amino acids were shielded from the destructive effects of high energy radiation by the ice and could survive tens to hundreds of millions of years if buried at least one centimeter deep in comets, icy moons, or planets.
Article in Icarus, Volume 220, Issue 2, Pages 647-659
|
 |
|
|
How Life Turned Left - 07.25.2012
Meteorites provide a record of chemical processes in the early solar system and may have delivered the left-handed protein amino acids common to all terrestrial life. A predominance of left- over right-handed amino acids has been found in some meteorites, but the origin of these excesses remains unclear. Analyses of the Tagish Lake meteorite by GCA scientists (D. Glavin, J. Elsila, A. Burton, M. Callahan, and J. Dworkin) and D.K. Herd (U. of Alberta) showed L-excesses (up to ~60%) in certain proteinogenic amino acids that cannot be attributed to terrestrial contamination. The excesses appear to have formed during aqueous alteration on the asteroid and support the hypothesis that L-amino acid enrichments formed by non-biological processes before the emergence of life.
Journal of Meteoritics and Planetary Science Paper
|
 |
|
|
X-ray Outbursts Provide a Glimpse of Circumstellar Disks around Young Solar-type Stars - 07.03.2012
Because of their high energies and penetrating power, X-rays play a central role in the ionization of the disks surrounding young stars. The ubiquitous and strong X-ray emission in young Solar-type stars influence protoplanetary disk evolution via processes such as ionization, direct induction of chemical reactions, and modification of grain surfaces. GCA scientists K. Hamaguchi and R. Petre together with their Co-investigators in ESA obtained light curves of multiple-year X-ray outbursts of V1647 Ori using Chandra, Suzaku and XMM-Newton space observatories. They concluded that the cyclic X-ray changes represent the appearance and disappearance of hot regions on the star that rotate in and out of view. The hot spots represent the footprints of magnetically driven accretion flows from the disk to the surface of the young star. To reach the high temperatures associated with X-ray emission, matter must be hitting the protostar at a speed of about 4.5 million mph (2,000 km/s). The hot spots could reach temperatures some 13,000 times hotter than anywhere else on the star. This result clearly demonstrates that hard X-ray-emitting plasma can be present in long-lived accretion footprints at the surfaces of protostars, and thereby constrains the geometry of magnetospheric accretion in early protostellar evolutionary stages.
|  |
|
|
"Lunch and Learn" Panel Discussion on Astrobiology - 5.17.2012
GCA scientists joined Marc Kaufman, Washington Post reporter and the author of the highly acclaimed book "First Contact" in a "Lunch and Learn" panel discussion for GSFC employees to provide an overview of the scientific endeavors in the search for life beyond Earth. The GCA scientists are M. Callahan, D. Glavin, and P. Conrad (Deputy PI) of the SAM Instrument on the Mars Science Laboratory.
|  |
|
|
GCA Scientists to Develop Miniaturized Instrument for In-situ Organics Detections - 04.14.2012
Goddard scientists (S. Getty, W. Brinckerhoff, M. Callahan, J. Elsila) recently won funding from the Planetary Instrument Definition and Development Program to develop a miniature two-step tandem laser time-of-flight mass spectrometer (L2MS). The L2MS instrument can measure complex nonvolatile organic molecules using advanced laser desorption/ionization (LDI) techniques on solid samples such as "intact" meteorites and planetary rock and ice. The advanced LDI protocols were developed for the miniature L2MS prototype under the auspices of GCA, and have been applied to analyses of meteorites such as Murchison. The instrument is targeted for implementation on future missions to outer planetary satellites, such as Titan or Europa, which are each high-priority astrobiology targets.
|  |
|
|
Both Hot and Cold Chemistry form Amino Acids in Carbonaceous Meteorites - 03.09.2012
Asteroids and their fragments have impacted the Earth for the last 4.5 billion years. Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. GCA scientists have found amino acids in 13 Antarctica carbonaceous meteorites (CV and CO carbonaceous chondrites and ureilites) that experienced high temperatures in their history. They had previously discovered amino acids in carbon-rich meteorites (CI, CM, and CR carbonaceous chondrites) that experienced much lower temperatures. Their analyses showed that cosmochemical selection mechanisms seem to exist that favors formation of certain classes of amino acids with cold chemistry and other classes with hot chemistry.
Meteoritics and Planetary Science Paper
|
 |
|
> Previous News Releases: 2011 2010 2009 |
|
|
|
Home
