The Venus Life Equation

Three factors for which reasonable constraints exist that may point to favorable habitability conditions in the middle Venus atmosphere. Shown are upper and lower limits of temperature, pressure and pH prevailing in Venus clouds in the height range 45-70 km from its surface in the context of selected limit values for terrestrial life. Future missions may help to constrain additional major habitability variables such as water availability and ultraviolet radiation flux in this altitude range.

Ancient Venus and Earth may have been similar in crucial ways for the development of life, such as liquid water oceans, land-ocean interfaces, the favorable chemical ingredients and energy pathways.

If life ever developed on, or was transported to, early Venus from elsewhere, it might have thrived, expanded and survived the changes that have led an inhospitable surface on Venus today. Today the Venus cloud layer may provide a refugium for extant life. We introduce the Venus Life equation: a theory- and evidence-based approach to calculate the probability of extant life on Venus, L, using three primary factors of life: Origination, Robustness, and Continuity.

We evaluate each of these factors using our current understanding of Earth and Venus environmental conditions from the Archean to the present. We find that probability of origination of life on Venus is similar to that of the Earth and argue that the other factors are nonzero, yielding a probability of extant life of Venus of 0.1 or less. The Venus Life Equation identifies poorly understood factors that can be addressed by direct observations with future exploration missions.

Noam R. Izenberg, Diana M. Gentry, David J. Smith, Martha S. Gilmore, David Grinspoon, Mark A. Bullock, Penelope J. Boston, Grzegorz P. Slowik

Comments: Submitted to Astrobiology for Venus Special issue. 25 pages, 3 figures. Also to be submitted as white paper in shortened form to Planetary and Astrobiology Decadal Survey
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Popular Physics (physics.pop-ph)
Cite as: arXiv:2007.00105 [astro-ph.EP] (or arXiv:2007.00105v1 [astro-ph.EP] for this version)
Submission history
From: Noam Izenberg
[v1] Tue, 30 Jun 2020 21:06:55 UTC (2,016 KB)
https://arxiv.org/abs/2007.00105
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