The curious tale of searching for signs of life on Venus

This week on Space Curious: Fact checking a discovery of ‘signs of life’ in the Venusian clouds

Images captured by NASA's Mariner 10 spacecraft of Venus, a planet the size of Earth, wrapped in a dense, global cloud layer. (Image: NASA JPL)
Images captured by NASA's Mariner 10 spacecraft of Venus, a planet the size of Earth, wrapped in a dense, global cloud layer. (Image: NASA JPL) (NASA)

Earlier this year, Venus was in the spotlight because a group of international scientists said they found something peculiar in the Venusian clouds, the discovery would lead to new interest and excitement about potential robotic missions to Earth’s nearest neighbor.

A study published in the journal Nature Astronomy reported potential bio signatures, or something that might indicate life is present, had been found in the clouds of Venus. Using observations from the James Clerk Maxwell Telescope in Hawaii and ALMA, a Telescope Array in Chile, a team of astronomers, led by Professor Jane Greaves of Cardiff University, said they had found a gas called phosphine in the clouds of Venus.

It was a big deal because this particular kind of gas is thought to be made in only a few ways.

“At least on rocky planets, like Venus and Earth can only be made by life, whether microbe or in Earth’s case, human,” National Geographic contributor Nadia Drake said.

Drake covered the initial discovery and what happened after speaking to scientists who were and were not part of the research team. You can read her piece, “Promising sign of life on Venus might not exist after all”, at NationalGeographic.com.

“The argument that they were making was that there’s no way for phosphine to be produced by any known mechanism on Venus that does not involve life, which is a really extraordinary claim to be making,” Drake said. “That’s actually a very exciting, exciting discovery. Because if it’s true, it could be the first indication that we have found evidence for life beyond Earth.”

Venus is incapable of hosting life -- like you and me-- as we know it. The surface temperatures are about 900 degrees Fahrenheit. The clouds are primarily made of sulfuric acid. It’s no place humans will ever set foot.

The northern hemisphere is displayed in this global view of the surface of Venus. (Image: NASA/JPL) (WKMG 2020)

But scientists have speculated that the Venusian clouds could possibly support some form of life because on Earth we know of microbes that live in extreme environments.

After the initial excitement the process of peer review got underway, as it should for any scientific discovery.

Dr. Sarah Horst, a planetary scientist at Johns Hopkins University and the Department of Earth and Planetary Sciences, explained how big findings are confirmed.

Take coronavirus testing as an example.

“If you wanted to be really, really sure that you didn’t have COVID, you wouldn’t just get tested a bunch of times using the same one instrument, you would want to use a couple of different tests that exist,” Horst said.

With the data used for the phosphine discovery, several other groups of scientists attempted to independently confirm the results. The other two groups were unable to find this gas.

Horst, who specializes in studying atmospheres of other worlds, said there are challenges to detecting phosphine and in particular within the Venusian clouds.

“I would say (it’s) one of the hardest gases, if you were trying to detect it in the Venetian atmosphere, and not just with telescopes, but also there have been folks that have been looking at the Pioneer (Spacecraft) Venus data from from the atmosphere,” Horst said, referring to the NASA mission from the 1970s.

Listen to the full episode of Space Curious below to learn about the fascinating discovery and the process of fact-checking science.

Regardless of this recent mysterious discovery, a lot of people have their sights set on this hellish planet.

NASA is considering funding several missions to send to Venus, including two small spacecraft as part of its Discovery program, and also a multi-billion dollar flagship mission to Venus. In addition, private company Rocket Lab plans to send several spacecraft to Venus with the first launching in 2023.

Next time on Space Curious: the possibilities and perils of sending robots to Venus. That episode comes out Dec. 16.


Space Curious is a podcast from WKMG and Graham Media that answers your intergalactic questions. Hosted by WKMG space reporter Emilee Speck, each episode is designed to inspire everyone, from the space curious to the space fanatics. Questions for the podcast can be submitted here.

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About the Author:

Emilee is a digital journalist for News 6 and ClickOrlando.com, where she writes about space and Central Florida news. Previously, Emilee was a space writer and web editor for the Orlando Sentinel and a producer at the Naples Daily News.