[Baps] Frey Talk TODAY - September 19 @ 4:00 PM

[Sarah Stewart-Mukhopadhyay]

Harvard Origins Forum
September 19, at 4:00 PM
Biological Laboratories Lecture Hall (Room 1068), 16 Divinity Avenue.

Dr. Herbert Frey
Goddard Space Flight Center

A Late Heavy Bombardment on Mars:
How counting craters on Mars may provide insight into the question of
'impact frustration of life' on Earth (and maybe Mars).

Abstract:
Dating the largest (> 1000 km diameter) impact basins on Mars suggests
they all formed in a relatively short period of time, in what may have
been a martian analog of the Late Heavy Bombardment (LHB) on the Moon.
Crater retention ages for the large basins are derived from superimposed
smaller visible and buried impact basins which have signatures in Mars
Orbiting Laser Altimeter (MOLA) topography or in model crustal thickness
data derived from MOLA topography and Mars Global Surveyor gravity
models. If relative ages are converted to Hartmann-Neukum model
"absolute" ages, the time period for large basin formation on Mars may
have been <200 million years, consistent with the NICE model for a Late
Heavy Bombardment of the inner solar system about 3.9 billion years ago
(BYA). It has been suggested that such a bombardment may have frustrated
the origin of life on Earth until about 3.8 BYA. An alternative is that
life on Earth (and maybe Mars?) began earlier but was wiped out by large
impacts until the LHB ended. Our preliminary Mars data suggests the LHB
may have been a relatively brief impact "spike", which could permit an
early habitable period prior to the LHB.

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