http://astrobiology.gsfc.nasa.gov/RSS.XML Goddard Center for Astrobiology Web Updates http://www.nasa.gov/topics/solarsystem/features/life-components.html 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. http://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html A team of GCA scientists M. Callahan, J. Stern, D. Glavin. J. Dworkin and their co-investigators found diverse suite of nucleobases and terrestrially rare nucleobase analogs in twelve carbon-rich meteorites. These include denine and guanine, as well as hypoxanthine and xanthine DNA resembles a spiral ladder; adenine and guanine connect with two other nucleobases to form the rungs of the ladder. They are part of the code that tells the cellular machinery which proteins to make. Hypoxanthine and xanthine are not found in DNA, but are used in other biological processes. The discovery adds to a growing body of evidence that asteroids and meteorites are chemical 'factories' that may have been important sources of organic compounds required for the emergence of life on the early Earth. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules. http://www.nasa.gov/centers/goddard/news/features/2011/tagish-lake.html Dr. C. Herds at University of Alberta and his Co-Investigators, including Drs. D. Glavin, J. Dworkin, M. Callahan, and J. Elsila of GCA conducted detailed chemical and isotopic analyses of organic materials in four Tagish Lake meteorite specimens. These fragments are among the most pristine meteorite samples as they were collected on the Canadian frozen lake only days after the fall in January 2000 (http://www.sciencemag.org/content/290/5490/283.full) . Meteorites and asteroids may have been a source of organic matter (such as amino acids, nucelobases, monocarboxylic acids, sugars, and polycyclic aromatic hydrocarbons) that was necessary for the advent of life on Earth. These molecules probably originally formed in the interstellar medium and/or the solar protoplanetary disk, but was subsequently modified in the meteorites’ asteroidal parent bodies. The researchers found that the Tagish Lake meteorite is heterogeneous: the specimens have undergone different levels of hydrothermal alteration and at least some molecules of prebiotic importance were formed during the alteration on the parent body. http://www.nasa.gov/topics/solarsystem/features/young-jupiter.html Jupiter, the largest planet in the Solar System, is pivotal in shaping the configuration of the entire system, including the small bodies like comets and asteroids. The latest dynamical model shows that Jupiter could form much closer to the Sun at ~3 AU. Its early migratory path could bring it to within 1.5 AU, a region where many of the extrasolar ‘hot Jupiters’ have been observed around other stars. The model was built by Kevin Walsh of the Southwest Research Institute in Boulder, CO and his Co-Investigators, A. Morbidelli and S. Raymond in France, D. O’Brien at LPI in Arizona, and A. Mandell of Goddard Center for Astrobiology. The model demonstrates that Jupiter “tacked” (as in sailing) at 1.5 AU due to the formation of Saturn, then started moving outward towards its present location, leaving a planetesimal disk truncated at 1 AU that would later form the terrestrial planets. Mars had a smaller mass than Earth and Venus due to Jupiter's scattering of planet-forming materials at the location of Mars. The scheme is also consistent with the structure of the present-day asteroid belt. Jupiter’s migration initially empties but then repopulates the asteroid belt, with inner-belt bodies originating between 1 and 3 AU and outer-belt bodies originating between and beyond the giant planets. This explains the significant compositional differences across the asteroid belt with the outer belt populated with volatile-rich (icy) planetesimals and the inner belt with rocky planetesimals. Enough of the icy planetesimals had orbits crossing the terrestrial planets to account for the amount of water delivered to Earth during the period of late heavy bombardment. http://stacks.iop.org/2041-8205/734/L7 GCA scientists, Drs. Mumma, Bonev, Villanueva, Paganini, DiSanti and an international team of co-investigators measured episodic and spatial variations of eight primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, C2H2, H2CO, and NH3) and two product species (OH and NH2) in comet 103P/Hartley 2 (http://epoxi.umd.edu/) using high-dispersion infrared spectroscopy with large ground-based telescopes in Hawaii and Chile. The primary species were released directly from the comet nucleus, while the product species were produced in the coma. The team quantified the long- and short-term production rates of these volatiles over a three-month interval from October to December 2010 that encompassed the comet’s close approach to Earth, its perihelion passage, and flyby of the comet by the Deep Impact spacecraft during the EPOXI (http://www.nasa.gov/mission_pages/epoxi/index.html) mission. The short-term variations were consistent with nucleus rotation when compared with other observations. These measurements helped to determine the composition of Hartley-2, which is the only comet from the Kuiper Belt to be so categorized. http://iopscience.iop.org/0004-637X/728/1/18 A GCA team consisting of Drs. A. Mandell, L.D. Deming, M.J. Mumma and other colleagues used the Keck II telescope in Hawaii to obtain high-resolution near IR spectra of the exoplanet HD189733b. HD189733b is a transiting "hot Jupiter" from which strong thermal IR radiation has been detected by Deming et al 2006 (http://iopscience.iop.org/0004-637X/644/1/560). The team attempted to confirm a prior report of the detection of a bright methane emission from the planet using ground-based medium-resolution spectral data at 3.25 micron. http://www.nasa.gov/topics/solarsystem/features/left_hand_aminoacids.html A team of GCA scientists, Drs. D. Glavin, M. Callahan, J. Dworkin, and J. Elsila analyzed samples from nine carbon-rich meteorites (CI, CM, and CR carbonaceous chondrites). They found that most of these meteorites have an excess of left-handed amino acids. The amount of the excess seems to correlate with the degree of water alteration on the parent asteroid body. Life on Earth uses only left-handed amino acids. http://www.nasa.gov/topics/universe/features/molecule-fingerprints.html Diffuse Interstellar Bands (DIBs) have been observed in medium resolution spectra of the Andromeda and Triangulum galaxies taken by GCA scientist Martin Cordiner and his colleagues at Queen's University in Belfast, U.K. They had found these molecular fingerprints before in three other galaxies of the Local Group: our Milky Way, and the Large and Small Magellanic Clouds. http://www.nasa.gov/centers/goddard/news/releases/2010/10-111.html GCA scientists Drs. Jason Dworkin, Michael Callahan, and Jamie Elsila analyzed fragments of meteorites from the asteroid 2008 TC3 that were recovered from the Nubian Desert of northern Sudan after its impact on October 7, 2008 http://www.sciencemag.org/content/330/6010/1527.html The Moon has much less gold, platinum and palladium (highly siderophile elements) compared to Earth and Mars. These heavy elements were likely delivered to the mantles of Earth, Moon and Mars by asteroid impacts after completion of their respective core formation, via a process termed "late accretion". William Bottke at Southwest Research Institute in Boulder, Colorado and GCA Co-I Richard Walker at the University of Maryland built a dynamical model of late accretion with impactors of different sizes. http://www.nasa.gov/topics/solarsystem/features/europa-ice.html Mark Loeffler (GSFC) and Reggie Hudson (GCA) report reactions between two ices at temperatures hundreds of degrees below freezing without the need for radiation to drive the chemistry. The findings could revamp our understanding of Europa and other icy moons. http://www.nasa.gov/topics/solarsystem/features/dust-model.html Collaboration between scientists at two NASA Astrobiology Institutes: Marc Kuchner (GCA) and Chris Stark (Carnegie Institute of Washington), produced supercomputer simulations tracking the interactions of thousands of dust grains that show what the solar system might look like to alien astronomers searching for planets. The models also provide a glimpse of how this view might have changed as our planetary system matured. http://svs.gsfc.nasa.gov/vis/a010000/a010600/a010615/g_villanueva_youtube_hq.mov Dr. Geronimo Villanueva talks about the possibility of life on Mars, trips to remote telescopes, and the research opportunities at NASA in Spanish http://www.nature.com/nature/journal/v462/n7271/abs/nature08556.html Dr. L. Drake Deming of the Goddard Center for Astrobiology (GCA) has been named by the American Astronomical Society as the recipient of the 2010 Beatrice Tinsley Prize. The Tinsley Prize is awarded bi-annually for unusually creative or innovative research in astrophysics. Deming was cited for "...detecting thermal infrared emission from transiting extrasolar planets using the Spitzer Space Telescope. http://www.nasa.gov/mission_pages/epoxi/sun-glints.html In two new videos from NASA's Deep Impact spacecraft, bright flashes of light known as sun glints act as beacons signaling large bodies of water on Earth. These observations give scientists a way to pick out planets beyond our solar system (extrasolar planets) that are likely to have expanses of liquid, and so stand a better chance of having life.