K2-18b: did JWST really find evidence of life on this exoplanet?

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2024-06-06に共有
AD |  To try everything Brilliant has to offer for free for a full 30 days, visit brilliant.org/DrBecky and you'll also get 20% off an annual premium subscription. | Back in 2023, we saw the first ever claim that JWST had discovered a possible signature of life in the atmosphere of an exoplanet, a planet orbiting another star in our galaxy the Milky Way. But the evidence for the claim that dimethyl sulphide exists in K2-18b’s atmosphere was weak. Now, in the past few months of 2024, we’ve had two new papers analysing the data from K2-18b which both claim there are other models that can explain K2-18b just as well, with the same level of statistical backing. So what is going on here? So let's dive into what’s going on so you can all make up your own mind.

Madhusudhan et al. (2023; hycean world with DMS evidence) - arxiv.org/pdf/2309.05566.pdf
Shorttle et al. (2024; hydrogen atmosphere with magma ocean) - arxiv.org/pdf/2401.05864
Wogan et al. (2024; mini-Neptune) - arxiv.org/pdf/2401.11082
Hu et al. (2021; prediction of the molecules present in a hycean world atmosphere) - arxiv.org/pdf/2108.04745.pdf
Benneke et al. (2019; water vapour in K2-18b's atmosphere) - arxiv.org/pdf/1909.04642.pdf
Cloutier et al. (2019; K2-18b mass) - arxiv.org/pdf/1810.04731
Foreman-Mackey et al. (2015; K2-18b discovered in K2 data) - arxiv.org/pdf/1502.04715
Seager et al. (2013; biosignatures in hydrogen atmospheres) - arxiv.org/pdf/1309.6016.pdf

JWST proposal 2722 - www.stsci.edu/jwst/phase2-public/2722.pdf
JWST proposal 2372 - www.stsci.edu/jwst/phase2-public/2372.pdf

00:00 - Introduction
02:45 - What do we know about K2-18b so far?
05:21 - Madhusudhan et al. (2023) - K2-18b is a hydrogen atmosphere with a liquid water ocean with dimethyl sulphide
09:33 - Shorttle et al. (2024) - K2-18b has hydrogen atmosphere with a magma ocean
11:05 - Wogan et al. (2024) - K2-18b is just a mini-Neptune
13:19 - What data do we need to figure this out?
16:37 - Bloopers

My previous video on K2-18b:    • Did JWST find a MARKER OF LIFE in an ...  
My previous video on the markers for life JWST is looking for:    • JWST is hunting for these FOUR signs ...  

Video filmed on a Sony ⍺7 IV

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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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コメント (21)
  • @gleedads
    Awesome summary: "Promise me you'll bear all of this in mind...just because one model fits the data doesn't mean there aren't other models..." This is such a good summary of the essence of science that I will probably point my students at this video, whether we are studying anything to do with exoplanets or not.
  • @bujin1977
    One thing that blows my mind is that I went to university to study astrophysics not very long after the first exoplanet was discovered. I found it fascinating back then that we had the ability to detect planets around other stars. And now we're able to analyse the light passing through the atmospheres of these planets. I wonder where we'll be in another 30 years time.
  • @mastick5106
    "Well, this kind of confusion, of not knowing what the actual right answer is, is science in action and it's wonderful to see." This attitude is honestly the main reason I subscribed to your channel. I love it.
  • @SazzleCam
    1st rule of media: Don't let data & scientific analysis get in the way of selling a good story.
  • @jacobhald1377
    Just want to point out that magma means underground molten rock, where lava means topside molten rock. So a magma ocean would mean an underground ocean of molten rock. I guess that's sort of what we have right here at home in our own planet. In other words, we got K2-18b at home! :D
  • @tf454
    Dr. Becky videos are just pure gems. Thank you again.
  • @luudest
    Ok, we need to build a bigger telescope right now.
  • @RaeanneNichol
    I simply love your channel because you illustrate quite well how same data can be interpreted in many different ways. And which is why we need to keep asking questions and obtaining more data to better understand our universe just a little more clearly.
  • Awesome analysis. You break it down nicely for the layman. Appreciate you! Keep up the great work.
  • I was in high school when discovery of the first exoplanet was announced. And now, we might soon have evidence of life on them. It almost feels like science fiction.
  • @JeffLearman
    THANKS! I saw the headlines but didn't even bother to read, hoping it'd be covered here, especially if it wasn't the usual news hype.
  • I listen to this and am reminded of the old saying: Lies, damned lies and STATISTICS. Excellent explanation of something that goes so far over my head it could be in orbit 😊
  • Another great video... Thanks Dr. Becky <3 from Scotland
  • @seliasthemage
    I really like the way you cover this by talking through each of the papers.
  • Thanks so much for creating and sharing this informative video. Great job. Keep it up.
  • Thank you for this great report! I've subscribed and I'm looking forward to more. As I watched, I was paying as much attention to the data analysis as to K2-18b itself. I'm applying to a Masters program in economics, and for that I'll need to know statistics and other analytical tools. So as your video got toward the end I was thinking, OK, time to start on that. And hey ho there you go, you're talking about Brilliant and its new material on data analysis. Synchronicity -- you gotta love it. Thank you for that too. Cheers, Chris Schulman
  • Your excitement about hat you do is invigorating and I enjoy listening to you explain plausible possibilities of complex scenarios is mesmerizing. I'm a retired Industrial teacher and I know when someone is doing a great job. I do share your astronomical interest. Have a sunny day and a clear night!
  • @StEvEn-dp1ri
    As a non-scientist, but an armchair science enthusiast, it drives me crazy to see the claims that some of these "scientists" make using such imperfect data. The ambiguity in the data leaves way too much room for interpretation to make a claim this important.
  • @chadcrotts870
    Thank you as always for making the complex easy to understand for the casual observer.
  • @xantiom
    -Pack swimming suits! -Unpack swimming suits, pack fire proximity suits and lots of hydrogel! -Unpack the fire proximity suits, pack the gasmasks and bring a balloon