New study explains why Mars is RED

AD - Go to https://surfshark.com/drbecky and use code DRBECKY at checkout to get 4 extra months of Surfshark VPN | Mars is quite famously the red planet and it’s red colour has long been thought to be due to something known as hematite - a type of iron oxide - i.e. plain old rust. That’s what we’re all taught, it’s a common mineral on mars, it explains the colour. But a study published this month by Valantinas and collaborators claim it’s ferrihydrite that causes the red colour instead - a different type of iron oxide one with water, H2O, in its chemical make up. Once again pointing to the idea that Mars had a lot more water on its surface in the past, before becoming the desert world we know and love today. All our hopes of confirming this idea rest on the shoulders of the Perseverance rover and the Mars Sample Return mission...

Valantinas et al. (2025) - https://www.nature.com/articles/s4146...
Calvin et al. (2008) - https://agupubs.onlinelibrary.wiley.c...
Christensen et al. (2000) - https://agupubs.onlinelibrary.wiley.c...
Toulmin et al. (1976; NB behind paywall) - https://www.science.org/doi/10.1126/s...

00:00 Introduction
02:49 Why people thought hematite was responsible for the red colour this whole time
06:27 What Valantinas and collaborators have found in their study, and
08:10 What this means for how Mars evolved
11:49 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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