The Diversity of Exoplanetary Environments and the Search for Signs of Life Beyond Earth

Fuente: arXiv
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Main Authors: Seager, Sara, Petkowski, Janusz J., Bains, William
Format: Preprint
Published: 2025
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author Seager, Sara
Petkowski, Janusz J.
Bains, William
author_facet Seager, Sara
Petkowski, Janusz J.
Bains, William
contents Thousands of exoplanets orbit nearby stars, showcasing a remarkable diversity in mass, size, and orbits. With the James Webb Space Telescope now operational, we are observing exoplanet atmospheres and aiming to reach down to small, habitable-zone exoplanets in search of signs of habitability and possibly even biosignature gases. Given the scarcity of targets, it is imperative to embrace the known diversity and consider the range of exoplanets that might host life. We review how Earth life interacts with various atmospheric gases, noting that bacteria can survive in high concentrations of gases such as H2, He, CO2, and CO. Additionally, we consider the potential for life in alternative solvents and in cloud biospheres where rocky surfaces are excessively hot, as well as in hypothesized planetary global oceans. We highlight that life fundamentally requires metal ions for catalytic reactions, suggesting that environments without surface contact need meteoritic delivery to provide these essential elements. Despite today's observational limits, a suite of next-generation telescopes is being designed specifically for exoplanet studies, promising to expand our capabilities and understanding in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2506_11690
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Diversity of Exoplanetary Environments and the Search for Signs of Life Beyond Earth
Seager, Sara
Petkowski, Janusz J.
Bains, William
Earth and Planetary Astrophysics
Thousands of exoplanets orbit nearby stars, showcasing a remarkable diversity in mass, size, and orbits. With the James Webb Space Telescope now operational, we are observing exoplanet atmospheres and aiming to reach down to small, habitable-zone exoplanets in search of signs of habitability and possibly even biosignature gases. Given the scarcity of targets, it is imperative to embrace the known diversity and consider the range of exoplanets that might host life. We review how Earth life interacts with various atmospheric gases, noting that bacteria can survive in high concentrations of gases such as H2, He, CO2, and CO. Additionally, we consider the potential for life in alternative solvents and in cloud biospheres where rocky surfaces are excessively hot, as well as in hypothesized planetary global oceans. We highlight that life fundamentally requires metal ions for catalytic reactions, suggesting that environments without surface contact need meteoritic delivery to provide these essential elements. Despite today's observational limits, a suite of next-generation telescopes is being designed specifically for exoplanet studies, promising to expand our capabilities and understanding in the future.
title The Diversity of Exoplanetary Environments and the Search for Signs of Life Beyond Earth
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2506.11690