Name: Signs of Life Found on Venus
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The gas phosphine, made on Earth by microbial life forms, was found in Venus' atmosphere.

Could this mean there's life in our planetary neighbor's clouds?

The gas phosphine, made on Earth by microbial life forms, was found in Venus' atmosphere.

Signs of Life Found on Venus

Could this mean there's life in our planetary neighbor's clouds?

Space & Flight

Signs of Life Found on VenusPublished: September 25, 2020Narrator: Scientists might have just discovered signs of life on Venus.Clara Sousa-Silva: It feels game changing.Sara Seager: It is so unexpected but I never thought in my life that it would be something we should either look for, that we would find in Venus.Narrator: Venus is about the size of Earth, but blanketed by a thick atmosphere. The surface reaches more than 850 degrees—hot enough to melt lead—and the atmosphere is laced with sulfuric acid.Sousa-Silva: I mean, Venus used to be the popular planet to look for life.Narrator: Numerous spacecraft—like Magellan—have flown to the planet, but few have landed.Sousa-Silva: And then yes, in the eighties we did send a few probes that quite traumatically melted and that put us off. I get it. I would have, I would have not continued to try. The surface of Venus remains absolutely abominable for life.Seager: It would be terrible. It's so hot there. So, we wouldn't survive at all. The sulfuric acid droplets, they are deathly to any life form. If you put any kind of life into concentrated sulfuric acid, it'll just dissolve, dissolve instantly.Even though Venus' surface is way too hot for any kind of life, there's this Goldilocks zone. It’s a layer in the atmosphere that is not too hot, not too cold, but just right for life.Sousa-Silva: And that's exactly where we found phosphine.Narrator: Phosphine, the little molecule that might change how we understand life in the universe.Sousa-Silva: Phosphine is known for being a really terrible, deadly molecule. It was used as a chemical warfare agent in the first World War. And sadly, more recently by ISIS. All of which, because it's a really effective killer.Narrator: Phosphine is such a good killer of us because it reacts so easily with the oxygen that our bodies need to survive. But for life-forms that don’t require oxygen, phosphine isn’t toxic, and some actually produce it.Seager: Phosphine is associated with microbial life. It's found in oxygen-free environments, such as wetlands and swamps. It's associated with feces, so we know for sure that phosphine is associated with life here on Earth.Sousa-Silva: So a lot of my work was going, "Oh, if this life on Earth produces phosphine, could other non-oxygen loving alien life produce it too?"My original work had said, if you find phosphine on any terrestrial planet, it can only mean life. And that wasn't an outrageous claim until recently.Narrator: Then in late 2018, Clara got a strange email.Silva-Sousa: It was only when Jane Greaves contacted me about a year and a half ago saying, and I'll be paraphrasing here, cause I don't remember, “Uh, Clara, you're the phosphine expert and I think I found phosphine on Venus. Is that weird? Cause I think it's weird." Then I did freak out, because it is very weird.Narrator: Using the James Clerk Maxwell Telescope in Hawaii, astronomer Jane Greaves detected a hint of phosphine in Venus’ atmosphere.Seager: She found a signal phosphene, a somewhat weak signal, but it was enough to propose to use the more powerful ALMA—Atacama Large Millimeter Array Telescope—that is in the high deserts of Chile. And we observed Venus again and again, found phosphine. This time, much stronger, a much stronger signal.Silva-Sousa: Then we were sure the signal was real. So, we spent the rest of the year and a half that followed showing that phosphine was the most plausible explanation for that signal. And that if it is indeed phosphene, life, as strangely as that sounds, is the most plausible explanation for the phosphene.Narrator: The team used computer models of Venus’ atmosphere and geology to try to create phosphine without life. They failed.Seager: It's still very, very mysterious. There could be two different explanations, both of which are equally, in my mind, preposterous. One is that there is some unknown chemistry. Or phosphine might be produced by some kind of life in Venus' clouds.Silva-Sousa: So far, our technique has been proving all the things that it isn't, and we've exhausted everything we've got, with our knowledge of Venus and phosphine and chemistry and geology and planetary dynamics. We cannot make phosphine in any non-biological way that could justify the detection we got on Venus, but I'm sure plenty of people will now chip in with their own expertise. And, I can't wait to see what they come up with.Seager: This is the first step of a very long journey. And we, all we can say is we're confident we have a robust detection of phosphine gas in Venus's atmosphere and the rest is really just future research.Narrator: Some scientists are still skeptical that phosphine on Venus could only be created by life.Silva-Sousa: If it is indeed phosphine, unambiguously, so how do we prove it is life? And that is not trivial. And so I'm extremely excited that we did this on Venus next door, where we actually can go and check. So, when we get to that point, let's go look!Seager: We hope we can send a mission, a space mission to Venus, look for complex molecules that would be indicative of life. And maybe somehow even look for life itself.Narrator: And if we found it?Silva-Sousa: I think it could be game changing for everyone. Not just because it would mean that there's life next door, which in itself, I think is a big enough deal. It's very implausible that life can originate in both the planet like Earth and a planet like Venus, which are so different in so many ways, and it not be something that can also originate in a variety of other planets. And so life might not just be next door. It might just be extremely common and inevitable, which means that there's thousands and thousands of possibilities for life in the galactic neighborhood just waiting to be discovered. So yes, pretty big deal.

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Signs of Life Found on Venus

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Support Provided By

Explore More

Finding Life Beyond Earth

The Planets: Inner Worlds

Five Facts About Hot, Volcanic Venus