A NASA Astrobiology Institute-funded study led by Chris Dupont of the J. Craig Venter Institute indicates that environmental availability of trace elements over Earth's history influenced the selection of elements used by life as biological evolution progressed. Their results show that environmental concentrations of trace metals influenced which types of metal-binding proteins evolved, and the relative timing of their evolution.

The study implies that the geochemistry of the Archean ocean (>2.5 billion years ago) influenced both the evolution of metal-binding protein architectures and the selection of elements by the ancestors of modern Archaea and Bacteria (simple single cell organisms). Specifically, low Zn, Mo, and Cu concentrations in the Archean ocean likely prevented the widespread emergence and diversification of Eukaryotic life (including plants, animals, and fungi) until the oceans became oxic, relatively late in Earth's history. The study also revealed that although modern Archaea and Bacteria still predominantly use ancient metal-binding protein structures, most Eukaryotes use both early- and late- evolving structures. The paper appears in the May 24 Early Edition of PNAS.

Source: NAI Newsletter

Posted by Keith Cowing at 2:34 PM | Permalink | Comments (0)

Many of the most well known comets, including Halley, Hale-Bopp and, most recently, McNaught, may have been born in orbit around other stars, according to a new theory by an international team of astronomers led by Harold F. Levison, co-investigator on NAI's NASA Goddard Space Flight Center Team.

The team used computer simulations to show that the Sun may have captured small icy bodies from its sibling stars while it was in its birth star cluster, thereby creating a reservoir for observed comets. Their paper appears in the June 10, 2010 issue of Science Express.

Source: NAI Newsletter

Posted by Keith Cowing at 2:32 PM | Permalink | Comments (0)

Applications are invited for a Post-doctoral Research fellowship in Cosmochemistry. The successful applicant will join an active research program that investigates a wide variety of topics, including: 1) the chronology of the early solar system, 2) the nature and origin of the presolar dust that provided the raw material for the solar system, 3) the isotopic and chemical compositions and origins of primitive chondritic components, 4) samples returned by the Stardust Mission to comet Wild 2, and 5) solar wind samples returned by the GENESIS Mission. The main analytical tools for this research are the petrographic microscope, scanning electron microscope, electron microprobe, scanning Raman microscope, and ion microprobe. Minimum qualifications include a Ph.D. in a discipline relevant to cosmochemistry and experience in one or more of the following areas: cosmochemistry, meteoritics, isotope geo- or cosmochemistry, secondary ion mass spectrometry. Previous experience with one or more of the following is required (training will be provided for the others): petrographic microscope, scanning electron microscope, electron microprobe, Raman microscope, or ion microprobe. Experience with isotopic measurements or meteorite petrography is desired. The successful candidate will participate in one or more of the above research projects and will receive training and will be expected to become an independent user of the Cameca ims 1280 ion microprobe at the University of Hawai'i. The Fellowship will be for an initial period of 1 year with renewal for up to 2 additional years based on performance and on the availability of support.

Continue reading "Post-doctoral Researcher Position in Cosmochemistry, University of Hawai'i at Manoa" »

Posted by Keith Cowing at 1:29 PM | Permalink | Comments (0)

Stardust Comet Sample Return Mission"
Join us for the next NAI Director's Seminar!

Date/Time: Monday, March 29, 2010 11:00AM Pacific
Speaker: Don Brownlee (University of Washington), PI of Stardust Mission
Title: "Comets and the Early Solar System - Results from the Stardust Comet Sample Return Mission"

The NASA Stardust mission returned hundreds of samples of dust and small rocks from comet Wild 2. Like other Jupiter Family Comets, Wild 2 is believed to have formed beyond Neptune and stored in the Kuiper Belt until its recent migration into the inner solar system. Laboratory analyses of the comet samples provide a remarkably detailed look at the nature of solar nebula materials the resided at the edge of the solar system at the time that planets formed. Isotopically anomalous pre-solar grains have been found in the comet but their abundance is surprisingly low and it is clear that the bulk of micron and larger comet grains formed in the solar system by high temperature processes. The comet contains fragments of familiar high temperature components such as CAIs and chondrules that are well studied components of primitive meteorites. Common components formed in the 1400 to 2000K range These findings show that there was efficient radial transport of 1-100um grains over distances of 10's of AU. The comet seems to be a well preserved "grab bag" of components that formed in hot regions of the solar nebula. The low survival rate of pre-solar silicate grains at the edge of the solar nebula disk also suggests a low survival rate of pre-solar organics. It is clear that cometary icy and rocky materials formed in different environments. Stardust provided no information on ices but did it collect cometary organics including glycine. Comet-like bodies were probably the dominant form of planetesimal in the solar nebula and the Wild 2 results provide a very detailed look at the materials that made such bodies at the edge of the solar nebula.

For more information and participation instructions: http://astrobiology.nasa.gov/nai/seminars/detail/169 [Source NAI newsletter]

Posted by Keith Cowing at 1:25 PM | Permalink | Comments (0)

TO: NAI Newsletter distribution list
FROM: George Cody (NAI CIW team) and Douglas Whittet (NAI RPI team)
SUBJECT: Announcement and invitation to attend NAI "Workshop Without Walls": The Organic Continuum from the ISM to the Early Solar System

DATES: March 11-12, 2010

Workshop Website: http://astrobiology.nasa.gov/nai/2010vcworkshop

A two-day workshop using NAI remote communications tools will be held on March 11 and 12, 2010 to present topics spanning the cosmic evolution of organic complexity, from small molecule formation in interstellar clouds to organic synthesis and inventories in protoplanetary disks, the solar nebula, and primitive bodies such as comets and asteroids in our solar system.

Workshop topic areas include

* Interstellar Dust and the Organic Inventory of Protostellar Envelopes
* Organic Astrochemistry of Protoplanetary Disks
* Laboratory Studies of analog ISM and outer Solar System Materials
* Organics and Volatiles in Comets
* Organic matter in Interplanetary Dust particles.
* The Organic Inventory in Asteroids and Primitive Meteorites

This workshop is also a test of how to best use the advanced virtual communications capabilities of NAI to initiate greater cross-team awareness and dialog on a focused research area well represented across the NAI. What we learn from this will inform the greater NAI community.  

The workshop is open to all and will be accessible via internet browser- no special software or equipment is required. To receive connection details, please register on the NAI website: http://astrobiology.nasa.gov/nai/2010vcworkshop

Posted by Keith Cowing at 10:33 AM | Permalink | Comments (0)

Dust samples collected by high-flying aircraft in the upper atmosphere have yielded an unexpectedly rich trove of relicts from the ancient cosmos, report scientists from NAI's Carnegie Institution of Washington team in Earth and Planetary Science Letters. The stratospheric dust includes minute grains that likely formed inside stars that lived and died long before the birth of our sun, as well as material from molecular clouds in interstellar space. This "ultra-primitive" material likely wafted into the atmosphere after the Earth passed through the trail of an Earth-crossing comet in 2003, giving scientists a rare opportunity to study cometary dust in the laboratory.

Continue reading "'Ultra-Primitive' Particles Found in Comet Dust" »

Posted by Keith Cowing at 10:16 PM | Permalink | Comments (0)

Danny Glavin (speaker) and Jason Dworkin, "Southpaw Solar System: L-Amino Acid Excesses in Meteorites and the Implications for the Origin of Homochirality on Earth"

Abstract: Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of organic matter, including amino acids, by carbonaceous meteorites could have been an important source of the early Earth's prebiotic organic inventory. The earlier discovery of slight to significant excesses for several indigenous left handed

Continue reading "10/5 NAI Director's Seminar" »

Posted by Keith Cowing at 9:49 AM | Permalink | Comments (0)

NASA scientists have discovered glycine, a fundamental building block of life, in samples of comet Wild 2 returned by NASA's Stardust spacecraft.

"Glycine is an amino acid used by living organisms to make proteins, and this is the first time an amino acid has been found in a comet," said Dr. Jamie Elsila of NASA's Goddard Space Flight Center in Greenbelt, Md. "Our discovery supports the theory that some of life's ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts."

Elsila is the lead author of a paper on this research accepted for publication in the journal Meteoritics and Planetary Science. The research will be presented during the meeting of the American Chemical Society at the Marriott Metro Center in Washington, DC, August 16.

Continue reading "NASA Researchers Make First Discovery of Life's Building Block in Comet" »

Posted by Keith Cowing at 9:55 PM | Permalink | Comments (0)

Members of NAI's NASA Goddard Space Flight Center Team have a new paper in PNAS describing the distribution and enantiomeric composition of certain amino acids in carbonaceous meteorites. Their results show an increased amount of "left handed" isovaline in several meteorites, which helps to explain why all known life uses only left-handed versions of amino acids to build proteins.

"Finding more left-handed isovaline in a variety of meteorites supports the theory that amino acids brought to the early Earth by asteroids and comets contributed to the origin of only left-handed based protein life on Earth," said study co-author Danny Glavin.

The team also found a pattern to the excess. Different types of meteorites had different amounts of water, as determined by the clays and water-bearing minerals found in the meteorites. The team discovered that meteorites with more water also had greater amounts of left-handed isovaline.

[Source: NAI Newsletter]

Posted by Keith Cowing at 11:02 AM | Permalink | Comments (0)

Members of the Astrochemistry Laboratory propose and carry out measurements, observations and modeling of key rates and/or fundamental quantities that control important chemical processes in astrophysical and planetary environments or that yield the chemical and isotopic compositions of solar system bodies. Members also perform simulations of natural processes or synthesize simplified analog samples of natural materials in order to better understand the unexpected consequences of natural events or to record the spectroscopic properties of well characterized samples for comparison with observations. Deadline: Feb 1, 2009 http://fellowships.hq.nasa.gov/gsrp/research/detail.cfm?oppID=672

Source: [NASA Graduate Student Researchers Program (GSRP)]

Posted by Keith Cowing at 8:47 AM | Permalink | Comments (0)

According to an article published in the Washington Post, scientists studying the Murchison meteorite have found that it contains clues to the origin of chirality. Amino acids in nature have two forms, referred to as right- and left-handed, that are mirror images of each other. The proteins in living organisms, however, are only made from left-handed amino acids. The reason for this chirality is not understood, but this new research suggests it may stem from meteorites that rained down on the young Earth.

Source; NAI Newsletter

Posted by Keith Cowing at 8:18 PM | Permalink | Comments (0)

Scientists from NAI's Carnegie Institution of Washington Team have a new paper in Meteoritics and Planetary Science detailing their discovery of amino acids in two meteorites at concentrations ten times higher than levels previously measured in other similar meteorites. The result suggests that the early solar system was far richer in the organic building blocks of life than scientists had thought, and that fallout from space may have spiked Earth's primordial broth. [Source: NAI newsletter]

Posted by Keith Cowing at 8:31 PM | Permalink | Comments (0)

Scientists from NAI's University of Arizona Team have studied the outflow of VY Canis Majoris, an oxygen-rich supergiant star. Thier results show that, against expectations, an old, oxygen-rich star can synthesize a chemically varied molecular cocktail. The study is published in Nature, and a News and Views about the paper is also available. [Source: NAI Newsletter]

Posted by Keith Cowing at 8:23 AM | Permalink | Comments (0)

NASA is seeking representatives of the astronomical community to serve on the Primordial Polarization Program Definition Team (PPPDT). Members of the PPPDT will work in collaboration with NASA Headquarters and the astronomical community to provide input for a space-based Cosmic Microwave Background (CMB) polarization mission. The PPPDT will help provide technical input from the astronomy community on questions relating to the science mission and technology developments required for this investigation and will help disseminate information about such a mission to the community. Astronomers from the U.S. and other countries are eligible for membership.

Continue reading "NASA Primordial Polarization Program Definition Team - Representatives Needed" »

Posted by Keith Cowing at 3:44 PM | Permalink | Comments (0)

New work from NAI NASA Ames Research Center Team members and their colleagues published recently in PNAS suggests that the cause for much of the extended red emission, or ERE, is due to closed-shell cationic polycyclic aromatic hydrocarbon, or PAH, dimers. Their work sheds light on the processes involved in carbonaceous dust evolution in the interstellar medium. [Source: NAI Newsletter]

Posted by Keith Cowing at 11:00 PM | Permalink | Comments (0)

Cassini Radar Finds Hydrocarbon Lakes on Titan

"The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole. Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions."

Posted by Keith Cowing at 4:18 PM | Permalink | Comments (0)

Researchers from NAI's NASA Goddard Space Flight Center Team and their colleagues publish their analysis of two meteorites in the current issue of Meteoritics and Planetary Science. Their study revealed a suite of amino acids present in the meteorites that are not present in the Antarctic ice on which they were found. [Source: NAI Newsletter]

Posted by Keith Cowing at 10:53 AM | Permalink | Comments (0)

Andrey Bekker of NAI's Carnegie Institution of Washington Team and his colleagues have an article in press for Precambrian Research which details the carbon isotope record for the carbonate platform in the Great Lakes area.

Continue reading "Carbon Isotope Record from ~2.2 Ga Rocks in the Great Lakes Area" »

Posted by Keith Cowing at 10:54 AM | Permalink | Comments (0)

The Center for Meteorite Studies at Arizona State University is pleased to announce the 40th Anniversary of the Nininger Award for undergraduate and graduate students pursuing research in meteoritical sciences.

Continue reading "ASU Award for Students Pursuing Research in Meteoritical Sciences" »

Posted by Keith Cowing at 12:34 AM | Permalink | Comments (0)