Biosignatures & Paleobiology: April 2009

NAI's Archean Biosphere Drilling Project supported the acquisition of pristine drill core samples obtained from ancient rocks in Western Australia. New results from those studies, published in the current issue of Nature Geoscience, point toward an earlier start for oxygenic photosynthesis on the early Earth than previously thought.

Never before has an asteroid been both telescopically observed while in space, and then collected and analyzed after it's hit the Earth. NAI astrobiologists from the Carnegie Institution of Washington and the SETI Institute are part of the large, interdisciplinary team of scientists who undertook the investigation. Their results are published in a recent issue of Nature.

Analysis of the carbon content in the fragments of 2008 TC3, as it is known, showed it to be mostly graphite-like, indicating that at some point in the past the body had been subjected to extremely high temperatures. Nanodiamonds were also observed.

It's oxygen isotopic signature classifies it as a very rare type of meteorite known as a ureilite. Because astronomers took spectral measurements of 2008 TC3 before it hit the Earth, and can compare those measurements with the laboratory analyses, scientists will be better able to recognize ureilite asteroids in space.

[Source: NAI Newsletter]