Transfer Of Rocks Between Planetary Systems: Panspermia Revisited

By Keith Cowing
May 16, 2022
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Transfer Of Rocks Between Planetary Systems: Panspermia Revisited
Schematic diagram showing the processes necessary for the successful transfer of life from one planetary system to another (proceeding clockwise from the upper left to the lower left). Life must first arise on a habitable planet. Rocks that contain living biological material must then be removed from the planetary surface, and then ejected from the planetary system. After traveling through interstellar space, the rock must be captured by another planetary system and delivered to the surface of a potentially habitable planet. Finally, the biological material must thrive in its new environment.

Motivated by the recent discovery of interstellar objects passing through the solar system, and by recent developments in dynamical simulations, this paper reconsiders the likelihood for life bearing rocks to be transferred from one planetary system to another.

The astronomical aspects of this lithopanspermia process can now be estimated, including the cross sections for rock capture, the velocity distributions of rocky ejecta, the survival times for captured objects, and the dynamics of the solar system in both its birth cluster and in the field. The remaining uncertainties are primarily biological, i.e., the probability of life developing on a planet, the time required for such an event, and the efficiency with which life becomes seeded in a new environment.

Using current estimates for the input quantities, we find that the transfer rates are enhanced in the birth cluster, but the resulting odds for success are too low for panspermia to be a likely occurrence. In contrast, the expected inventory of alien rocks in the solar system is predicted to be substantial (where the vast majority of such bodies are not biologically active and do not interact with Earth).

Fred C Adams, Kevin J Napier

Comments: 18 pages, 3 figures, to appear in Astrobiology
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2205.07799 [astro-ph.EP (or arXiv:2205.07799v1 [astro-ph.EP] for this version)
Submission history
From: Fred C. Adams
[v1] Mon, 16 May 2022 16:44:49 UTC (2,932 KB)’

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