Sean Raymond (planetplanet.net)
Building crazy planetary systems on my blog planetplanet.net. Solar System formation. Exoplanets. Free-floating planets and interstellar objects. Astronomy poem book: amzn.to/3muytqo He/him.
- It's official. I just took over as the new director of the Laboratoire d'Astrophysique de Bordeaux (@labastrobordeaux)! It's a whole new gig -- wish me luck!
- My new paper with Nate Kaib explores what triggered the dynamical instability that took place among the giant planets in the young Solar System. We show that the flyby of a low-mass brown dwarf or free-floating planet could have done it (probability ~5%). ui.adsabs.harvard.edu/abs/2025arXi...
- Looks like the link's not working. You can access the paper here: arxiv.org/abs/2512.07979
- Last week, my son Zack shadowed me at my department for a week. I put him to work but I gave him a choice -- and he decided to simulate rings of planets and stars orbiting a black hole. And he wrote a blog post about it for your reading enjoyment (with gif!) planetplanet.net/2025/12/13/b...
- About 100 billion humans have walked the Earth. About 100 billion stars roam the Milky Way galaxy. About 10,000 humans have ever been paid to study the stars (if anyone has better data let me know). So, modern astronomers are each lucky to the tune of 1 in 10 million!
- If you live in France, a new documentary about 'Oumuamua comes out Thursday evening, starting at 9pm on the France 5. Replays on france.tv after I was scientific advisor (and I show up in several places), which was a great pleasure. www.francetvpro.fr/contenu-de-p...
- I just realized that a couple weeks ago was the fifth anniversary of the release of my astronomy poem book: Black Holes, Stars, Earth and Mars. www.amazon.com/dp/B08LFZZWGZ
- Here's a new article I wrote for @nautil.us about a new result hinting that variations in the cosmic ray flux hitting the Earth, which itself varies as the Sun oscillates vertically within the Galaxy, have a strong link to the diversity of microplankton. nautil.us/could-the-su...
- New animation of the ultimate engineered solar system for a talk I'm giving tomorrow at a sci-fi convention in Lithuania. It has 400 rocky planets in the habitable zone of a single Sun-like star It's perfectly stable (I simulated it out to about a billion years) planetplanet.net/2017/05/03/t...
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- In my new @nautil.us article, I use a lot of recent research to argue that rocky exoplanets on eccentric orbits are often very good candidates for life. (At least, eccentric/inclined orbits should not be used as a negative for habitability) nautil.us/wild-orbits-...
- Here's something new and weird -- eccentric rings of co-orbital planets. They are stable indefinitely, from an orbital point of view. Could they actually form and exist? planetplanet.net/2025/09/02/e...
- Flashback to 2012 when I ate the Sun (Photo from the top of Vulcano in Sicily)
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- Reposted by Sean Raymond (planetplanet.net)Today, *every* living prior leader of NASA's science directorate have released a joint letter condemning the proposed cuts to NASA science. These individuals every administration from Reagan to Biden, and all believe these cuts are insanely destructive: www.planetary.org/press-releas...
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- Reposted by Sean Raymond (planetplanet.net)The details are not yet finalized, but the budget bill would devastate NASA science and the future of US exploration in space and astronomy. Among many other things. 🔭🧪 www.planetary.org/articles/nas...
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- @nytimes.com article about Nate Kaib's and my recent paper on the future stability of the Solar System when passing stars are accounted for. www.nytimes.com/2025/06/28/s...
- Like dinosaurs, Saturn and Jupiter roamed They sculpted this system that humans call home The gas giants roared, the system unstable An ice giant planet fell right off the table! A whole ring of comets was launched to the stars The planets — bombarded — still bear the scars.
- I was the scientific advisor for the latest video by Balade Mentale about "World-Killer Planets: The Chaotic History of Planetary Systems" (in French) youtu.be/_6J9axX3r08?...
- The Lindy Effect and the stability of planetary systems. Here's one way of thinking about why planetary systems go unstable, and when. planetplanet.net/2025/06/11/t...
- A quick update about co-orbital rings of planets. This setup -- with 42 planets (each the same mass as Earth) sharing an orbit that is the same average distance as Earth (1 au) but super-eccentric -- is stable for at least 5 million years. (I'm running it out to a billion years to test)
- Need a quick book to read in the bath or at the beach? Even better -- a fun book of astronomy poems to read with your kids to get them interested in science and space? I humbly offer up my book, illustrated by my son Owen (back when he was 12). www.amazon.com/dp/B08LFZZWGZ
- Reposted by Sean Raymond (planetplanet.net)The NASA planetary science fleet chart if the president’s budget is enacted.
- Nice article about our recent paper (with Nate Kaib) on the future of the Solar System under the effect of passing stars. www.sciencenews.org/article/star...
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- New paper (Izidoro et al) We show that planets on very wide orbits -- such as the proposed Planet Nine -- are an inevitable consequence of dynamical instabilities that happen early in planetary systems, still in their (stellar) birth clusters Paper: rdcu.be/enVEi Quick thread 1/
