Solid Grains Ejected From Terrestrial Exoplanets As A Probe Of The Abundance Of life In the Milky Way

Searching for extrasolar biosignatures is important to understand life on Earth and its origin.

Astronomical observations of exoplanets may find such signatures, but it is difficult and may be impossible to claim unambiguous detection of life by remote sensing of exoplanet atmospheres.

Here, another approach is considered: collecting grains ejected by asteroid impacts from habitable exoplanets in the Milky Way and then traveling to the Solar System. The optimal grain size for this purpose is around 1 μm, and about 105 such grains are expected to be accreting on Earth every year, which may contain biosignatures of life that existed on their home planets.

These grains may be collected by detectors placed in space, or extracted from Antarctic ice or deep-sea sediments, depending on future technological developments. In the foreseeable future, this is probably the only approach for humankind to search for extrasolar biosignatures by directly sampling biological materials.

Tomonori Totani

Comments: 8 pages, no figure. Submitted for publication
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Populations and Evolution (q-bio.PE)
Cite as: arXiv:2210.07084 [astro-ph.EP] (or arXiv:2210.07084v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2210.07084
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Submission history
From: Tomonori Totani
[v1] Thu, 13 Oct 2022 15:10:56 UTC (10 KB)
https://arxiv.org/abs/2210.07084
Astrobiology