The Venusian mystery of phosphine and ammonia

The planet Venus is an enigma in many ways. It is a sister planet to Earth and is also relatively within range of our instruments and probes, but we know very little about what goes on on its surface or even within its dense atmosphere. Much of this is, of course, because planets like Mars have all the orbiting probes and explorers running around its barren, radiation-battered surface, but we have had atmospheric probes descend through Venus’ atmosphere, so far with little success. In 2020 speculation arose about the detection of phosphine in Venus’ atmosphere, causing both excitement and a lot of skepticism. Anyway, at the recent National Astronomy Meeting (NAM 2024) the current state of Venusian knowledge was discussed, even prompting The Guardian to report on it.

In addition to phosphine, there is speculation that ammonia may also be detected on Earth, which could be indicative of organic processes and thus potentially life. Related research has indicated that common amino acids essential for life on Earth would be stable even in sulfuric droplets such as those in the atmosphere of Venus. Following criticism of the original 2020 paper on phosphine, (Jane S. Greaves) et al. repeated their observations based on the comments, although it is clear that the observation of phosphine gas on Venus is not a simple binary matter.

The same is true for ammonia, which, if present in the clouds of Venus, would be a huge discovery, according to research by (William Bains) and his colleagues in PNAS It could explain many curious observations in the atmosphere of Venus. With so much uncertainty in remote observations, it is clear that the only way to answer these questions is with future missions to Venus, which unfortunately remain quite rare.

If there is indeed life on Venus, it will have to wait a while longer to evolve before we can go and check it out.