A new UK-led space mission aims to collect first-hand evidence that could support the long theorized presence of microbial life dwelling in the heavy clouds encircling Venus.
In recent years, astronomers have detected unexpected signatures of phosphine and ammonia gases on Venus, both of which are considered potential biomarkers, as they are byproducts of biological and industrial processes that occur on Earth.
Professor Jane Greaves of Cardiff University is leading the team behind the VERVE (Venus Explorer for Reduced Vapours in the Environment) mission, which will send a CubeSat to probe Venus’s clouds. The mission was unveiled at the Royal Astronomical Society’s National Astronomy Meeting, held this week in Durham, England.
Seeking Biosignatures on Venus
VERVE will seek out and map hydrogen-containing gases, first reported in 2020 in a paper that revealed observations of phosphine in Venus’s atmosphere. However, that finding met early resistance, as follow-up studies failed to replicate the detection of phosphine.
To clarify the gas’s behavior, researchers using Hawaii’s James Clerk Maxwell Telescope began a long-term study of Venus’s atmosphere, called the JCMT-Venus project. Their research uncovered an intriguing pattern: the phosphine levels appear to follow a day-night cycle, suggesting that sunlight may continually destroy the gas, only for it to be replenished overnight. Additionally, phosphine levels vary between different regions of the planet.
Ammonia, the second puzzling gas, was publicly reported just last year at the National Astronomy Meeting in Hull, England. Like phosphine, ammonia is primarily known to form through industrial and biological processes on Earth, with no known abiotic mechanism explaining its abundance on Venus.
“Our latest data has found more evidence of ammonia on Venus, with the potential for it to exist in the habitable parts of the planet’s clouds,” Professor Greaves said. “There are no known chemical processes for the production of either ammonia or phosphine, so the only way to know for sure what is responsible for them is to go there.
The VERVE Mission
While the project is budgeted at € 50 million, it will only be a tag-along, making its journey on the back of the European Space Agency’s 2031 EnVision mission. VERVES’s CubeSat would part ways once the missions reach Venus, conducting an independent survey from EnVision’s work.
“The hope is that we can establish whether the gases are abundant or in trace amounts, and whether their source is on the planetary surface, for example in the form of volcanic ejecta,” Professor Greaves said. ”Or whether there is something in the atmosphere, potentially microbes that are producing ammonia to neutralise the acid in the Venusian clouds.”
“This may explain some of the apparently contradictory studies and is not a surprise given that many other chemical species, like sulphur dioxide and water, have varying abundances, and may eventually give us clues to how phosphine is produced,” said Dr Dave Clements, of Imperial College London, who is the leader of the JCMT-Venus project.
Life on Venus
Venus’s surface is extraordinarily hot—reaching temperatures above 850 degrees Fahrenheit—making it likely inhospitable to life. However, about 31 miles above the surface, conditions in the Venusian atmosphere are more Earth-like, with temperatures ranging from 85 to 150 degrees Fahrenheit and pressures similar to those at sea level on Earth.
Astronomers also believe Venus may once have had a much cooler surface. Some theorists suggest that life could have emerged under those earlier, more temperate conditions, and that microbial remnants might persist today, clinging to existence in the harsh upper atmosphere, much like Earth’s extremophiles do in similarly unforgiving environments.
While the presence of ammonia and phosphine strengthens the case for investigating possible life on Venus, only a mission capable of directly sampling its atmosphere can provide the answers scientists are seeking.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.