The Curious Question of Life on Venus

Venus should be a priority for future visits, but not because of the surprising discovery of a biomarker in its atmosphere this week.

The Physics arXiv Blog iconThe Physics arXiv Blog
By The Physics arXiv Blog
Sep 16, 2020 1:45 PMSep 17, 2020 3:52 PM
Venus - NASA/JPL
Venus from Mariner 10. (Credit: NASA Jet Propulsion Laboratory)

Newsletter

Sign up for our email newsletter for the latest science news
 

Life has altered our planet to such an extent that its effects are visible from space. And not just from low Earth orbit. The signature of life is visible light years from here, thousands of billions of kilometers away. If intelligent civilizations have emerged on other stars, the signs of life on Earth should have been all too clear.

These signs are called biosignatures. Earth’s atmosphere contains high levels of oxygen and ozone, highly reactive molecules that should have long ago reacted with other compounds and disappeared if they were leftovers from the formation of the Solar System. Instead, their presence suggests that something on Earth’s surface is producing them in prodigious quantities. The same is true of methane, which breaks down easily in sunlight.

Another is phosphine, a toxic, flammable gas with a characteristic smell of garlic or rotting fish. Phosphine is highly reactive and so survives for only a short time. Its presence in Earth’s atmosphere at the level of parts per trillion suggests it must be constantly produced, in this case by anaerobic bacteria.

That’s why the discovery of phosphine in the atmosphere of Venus at parts-per-billion levels made headlines this week. Jane Greaves from the University of Cardiff and colleagues say there is no known way for phosphine to be produced on Venus by known geochemical or photochemical processes. This raises the possibility that biological processes could be responsible.

0 free articles left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

0 free articlesSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!

Subscribe

Already a subscriber?

Register or Log In

Stay Curious

Sign up for our weekly newsletter and unlock one more article for free.

 

View our Privacy Policy


Want more?
Keep reading for as low as $1.99!


Log In or Register

Already a subscriber?
Find my Subscription

More From Discover
Stay Curious
Join
Our List

Sign up for our weekly science updates.

 
Subscribe
To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2025 LabX Media Group