AD | Join me in reading Nautilus by heading to http://joinnautilus.com/drbecky where you can get 15% off a membership to Nautilus, perfect for any science enthusiast. | We only know of one planet in the universe that hosts life: Earth. So when we search for other life out there in the Universe we look for what we know. We look for water, and ozone, and methane, and a whole bunch of carbon containing molecules because we know that those ingredients point to life here on Earth. But what if life out there in the Universe is NOT as we know it, and we’re missing the signs because it doesn’t have the same signatures of Earth-life?! This is a real possibility, and there are astrochemists and astrobiologists out there who are working through all the options of what we think life could be like. So let’s chat about the fundamental biochemistry of life and pick out a few things that could be different to Earth…
Petkowski et al. (2020; silicon as a potential building block for life) –
Petkowski et al. (2025; PNA stable in sulphuric acid) –
Duzdevich et al. (2025; complex structures in sulphuric acid) –
Greaves et al. (2021; phosphine detected in clouds of Venus) –
Madhusudhan et al. (2025; dimethyl sulphide on exoplanet K2-18b) –
00:00 Introduction
02:59 Solvents: if it’s not water like on Earth, what could life use instead?
06:20 Solvents: Liquid carbon dioxide
07:44 Solvents: Liquid sulphur
08:38 Solvents: Liquid sulphuric acid
12:20 Organics: if it’s not carbon based life like on Earth, what could it be instead?
14:55 Organics: Silicon-based life
16:37 Chirality: a mirror image to life on Earth?
18:39 How we’d even find life as we don’t know it
22:02 Bloopers
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: https://www.fiverr.com/mgs_editing
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👩🏽💻 I’m Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). 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.
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