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Paleobiology & Biosignatures: August 2013


At optical wavelengths, an exoplanet's signature is essentially reflected light from the host star - several orders of magnitude fainter. Since it is superimposed on the star spectrum its detection has been a difficult observational challenge.

Professor Steven Benner will tell geochemists gathering today (Thursday, 29 August) at the annual Goldschmidt conference that an oxidized mineral form of the element molybdenum, which may have been crucial to the origin of life, could only have been available on the surface of Mars and not on Earth.

The characterization of the atmospheres of habitable-zone Earth-mass exoplanets that transit across main-sequence stars, let alone the detection of bio-markers in their atmospheres, will be challenging even with future facilities. It has been noted that white dwarfs (WDs) have long-lived habitable zones and that a large fraction of WDs may host planets.

Astrobiologists have shown that a key element for life on Earth was likely delivered to our planet on meteorites. Their work indicates that the early Earth was bombarded by meteorites that provided reactive phosphorus. When released in water, this phosphorus could have been incorporated into prebiotic molecules.

The NAI team, Virtual Planetary Laboratory (VPL), is interested in how to determine if planets orbiting others stars exhibit signs of life, "biosignatures."

In a new study published in Philosophical Transactions of the Royal Society B, scientists funded by the NASA Astrobiology Institute (NAI) advance a theory about life's origins based on the idea of "reservoir-mediated energy."