Transfer of Life Between Earth and Venus with Planet-Grazing Asteroids

Recently, phosphine was discovered in the atmosphere of Venus as a potential biosignature.

This raises the question: if Venusian life exists, could it be related to terrestrial life? Based on the known rate of meteoroid impacts on Earth, we show that at least ∼6×105 asteroids have grazed Earth’s atmosphere without being significantly heated and later impacted Venus, and a similar number have grazed Venus’s atmosphere and later impacted the Earth, both within a period of ∼105 years during which microbes could survive in space.

Although the abundance of terrestrial life in the upper atmosphere is unknown, these planet-grazing shepherds could have potentially been capable of transferring microbial life between the atmospheres of Earth and Venus. As a result, the origin of possible Venusian life may be fundamentally indistinguishable from that of terrestrial life.

Amir Siraj, Abraham Loeb
Comments: 3 pages, 1 figure; submitted for publication
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2009.09512 [astro-ph.EP] (or arXiv:2009.09512v1 [astro-ph.EP] for this version)
Submission history
From: Amir Siraj
[v1] Sun, 20 Sep 2020 20:00:12 UTC (90 KB)
https://arxiv.org/abs/2009.09512
Astrobiology, Panspermia,