Uploaded July 2026 | Updated September 2026, 2 weeks ago
SO you see a headline like this, “I’m Convinced We Found Evidence of Life on Mars in the 1970s” and you might think “yeah right” said with a very healthy dose of scientific skepticism. But this article is actually written by one of the lead scientists for NASA’s Viking mission that landed on Mars, specifically the lead for an experiment looking for evidence of life.
The experiment grabbed some Martian soil and searched for evidence of microbes that eat food and nutrients to survive, like we as humans do, rather than plants that photosynthesise light to survive.
So the instrument dripped a "soup" of lots of organic nutrients mixed in with a bunch of radioactive carbon onto some Martian soil. If there were any microbes in the soil they’d eat the nutrients in the radioactive soup, they would then breathe out some radioactive gas, which sensors on the instrument would then pick up.
And that’s exactly what they found, a bunch of radioactive gas given off by Martian soil mixed with a nutrient rich radioactive soup. Not as much as if you did the same thing with Earth soil, but still more than if you mix it with a bunch of Moon dust.
And although Levin and his collaborator Straat searched for a chemical reaction to explain what they saw, they couldn’t recreate the result in the lab with any known chemistry. And the result is still unexplained 50 years later.
Now all the other experiments on board Viking searching for life on Mars, didn’t find anything. So this unexplained result was lumped together with those as probably just unknown chemistry.
But given all we now know about Mars, that it once had liquid water flowing on its surface, or that organic molecules, that are the building blocks for the ingredients for life, are found in Martian soil, perhaps 50 years on from Viking it’s time to look at the data again.
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: martino.freelance@gmail.com
Video produced by Marina Hui & Dr Becky Smethurst
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📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
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👕 My merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com
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🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
---
🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
SO you see a headline like this, “I’m Convinced We Found Evidence of Life on Mars in the 1970s” and you might think “yeah right” said with a very healthy dose of scientific skepticism. But this article is actually written by one of the lead scientists for NASA’s Viking mission that landed on Mars, specifically the lead for an experiment looking for evidence of life.
The experiment grabbed some Martian soil and searched for evidence of microbes that eat food and nutrients to survive, like we as humans do, rather than plants that photosynthesise light to survive.
So the instrument dripped a "soup" of lots of organic nutrients mixed in with a bunch of radioactive carbon onto some Martian soil. If there were any microbes in the soil they’d eat the nutrients in the radioactive soup, they would then breathe out some radioactive gas, which sensors on the instrument would then pick up.
And that’s exactly what they found, a bunch of radioactive gas given off by Martian soil mixed with a nutrient rich radioactive soup. Not as much as if you did the same thing with Earth soil, but still more than if you mix it with a bunch of Moon dust.
And although Levin and his collaborator Straat searched for a chemical reaction to explain what they saw, they couldn’t recreate the result in the lab with any known chemistry. And the result is still unexplained 50 years later.
Now all the other experiments on board Viking searching for life on Mars, didn’t find anything. So this unexplained result was lumped together with those as probably just unknown chemistry.
But given all we now know about Mars, that it once had liquid water flowing on its surface, or that organic molecules, that are the building blocks for the ingredients for life, are found in Martian soil, perhaps 50 years on from Viking it’s time to look at the data again.
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: martino.freelance@gmail.com
Video produced by Marina Hui & Dr Becky Smethurst
---
📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
---
👕 My merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com
---
🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
---
🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
