One of the most remarkable scientific developments of the last couple of decades is the idea that life could exist elsewhere in our own solar system. Quite a few worlds are thought to have possible habitats: Mars, some of the moons of the giant outer planets, and the dwarf planets Pluto and Ceres. Even the planet Venus has been added to the list.

Venus would appear to be as unlikely a home for life as you could ever imagine. Its atmosphere is extremely hot, dense, and toxic. And it’s topped by clouds of sulfuric acid. Yet a few observations have hinted that microscopic life could inhabit those clouds.

Some observations have shown dark “mats” inside the clouds — a possible signature of bacteria. And a couple of years ago, a team reported evidence of phosphine in the clouds. Here on Earth, phosphine is a byproduct of life.

Follow-up work by other groups, though, discounts that possibility. The most recent is a study using SOFIA — an airborne observatory. It scanned Venus’s clouds in November of 2021. And it found no evidence of phosphine. In fact, scientists say there couldn’t be more than about one part per billion.

Even so, few are ready to give up on the possibility of life in the clouds of this inhospitable world.

Venus is the “evening star.” It’s quite low in the southwest at sunset, well to the lower right of the crescent Moon. The fainter planet Mercury is a little above Venus.
 

Script by Damond Benningfield