Venusian phosphine: a 'Wow!' signal in chemistry?

TL;DR

The paper discusses the surprising potential detection of phosphine in Venus's atmosphere, which challenges existing models and suggests unknown processes or possible microbial life.

Contribution

It summarizes the Venusian phosphine discovery, analyzes potential sources, and highlights the implications for Venusian chemistry and possible biosignatures.

Findings

Detection of phosphine in Venus's clouds is unexpected and unexplained by current models.

No known geological or atmospheric process accounts for the observed phosphine levels.

The presence of phosphine could indicate unknown chemistry or microbial life in Venus's atmosphere.

Abstract

The potential detection of ppb levels phosphine (PH3) in the clouds of Venus through millimeter-wavelength astronomical observations is extremely surprising as PH3 is an unexpected component of an oxidized environment of Venus. A thorough analysis of potential sources suggests that no known process in the consensus model of Venus' atmosphere or geology could produce PH3 at anywhere near the observed abundance. Therefore, if the presence of PH3 in Venus' atmosphere is confirmed, it is highly likely to be the result of a process not previously considered plausible for Venusian conditions. The source of atmospheric PH3 could be unknown geo- or photochemistry, which would imply that the consensus on Venus' chemistry is significantly incomplete. An even more extreme possibility is that strictly aerial microbial biosphere produces PH3. This paper summarizes the Venusian PH3 discovery and the scientific debate that arose since the original candidate detection one year ago.