On 14 September 2020, a team of astronomers led by Dr Jane Greaves of Cardiff University announced the detection of phosphine, a potential biomarker, in the atmosphere of Venus. On Earth, phosphine can result from natural processes such as lightning and volcanic activity, but only in small amounts; by comparison, the amount of phosphine detected in Venus' atmosphere is relatively large. The only known processes that produce phosphine on Earth in similar quantities are biological in origin.

It must be stressed that this does not mean that there is life on Venus. What has been announced is a signal that is a possible sign of life, with a strength for which there are no plausible known abiotic explanations. There may, of course, be currently unknown methods of producing it in the amounts required. But this is still an exciting signal that warrants more investigation.

For more information, the Royal Astronomical Society have an excellent primer here.