Posted byDaniella Scalice
May 20, 2009
Microbial Habitability During the Late Heavy Bombardment
In a new paper in the current issue of Nature, NAI Postdoctoral Fellow Oleg Abramov at the University of Colorado, Boulder leads a modeling study investigating the degree of thermal metamorphism of the Late Heavy Bombardment (LHB) on the crust of the young Earth. The models were designed to recreate the effect of the LHB on the Earth as a whole, with special attention to the impact on a possible subsurface or near-surface primordial microbial biosphere.
The team’s analyses revealed that there is no plausible situation in which the habitable zone could have been fully sterilized, at least since the primary accretion of the planets ended, and the postulated impact origin of the Moon. The authors conclude that subsurface microbial life could have persisted throughout the bombardment. They also propose that multiple, impact-induced temperature anomalies could have driven widespread hydrothermal activity, and that this was conducive to life’s emergence and early diversification. The study was funded by NAI and NASA’s Exobiology Program.