Building crazy planetary systems on my blog planetplanet.net. Solar System formation. Exoplanets. Free-floating planets and interstellar objects. Astronomy poem book: http://amzn.to/3muytqo He/him.https://bsky.app/profile/planetplanet.bsky.socialhttps://bsky.app/profile/planetplanet.bsky.social/post/3mrppvl5x422rIn this new paper we showed that interstellar objects can be captured as a byproduct of stars flying by each other in the Galaxy (no planets involved). It only works for strong-enough encounters, probably just a few for the Sun during its history. It means that all stars have (sparse) Oort clouds [contains quote post or other embedded content]28 Jul 2026 15:26 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mrppvl5x422rhttps://bsky.app/profile/planetplanet.bsky.social/post/3mq2k2mhz3k2aI fell asleep and forgot my June 15th tradition of reminding the world that something amazing may have happened on June 15, 2014 -- but no one on Earth saw it.. https://planetplanet.net/2014/06/04/something-amazing-will-happen-on-june-15th-but-no-one-on-earth-will-see-it/07 Jul 2026 11:50 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mq2k2mhz3k2ahttps://bsky.app/profile/planetplanet.bsky.social/post/3mpizp3zpi227For #AsteroidDay, here is a good ol' poem about, well, asteroids! https://planetplanet.net/2020/06/30/asteroids-the-poem/30 Jun 2026 12:42 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mpizp3zpi227https://bsky.app/profile/planetplanet.bsky.social/post/3mpiqnomuoc2hA nice write-up of a new paper by Nate Kaib and myself by @starstryder.space. The punchline: the orbits of long-period comets appear to hold a signature of the flyby of the star HD 7977, which happened 2.5 million years ago! https://phys.org/news/2026-06-ancient-stellar-flyby-period-comets.html30 Jun 2026 10:01 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mpiqnomuoc2hhttps://bsky.app/profile/planetplanet.bsky.social/post/3mnvxaabkzs2aI never thought I'd get the chance to shake hands with the president and have a one-on-one chat -- for a solid 15 seconds, during which one subject of conversation was, indeed, my tie (thanks to Marisa for suggesting it!)10 Jun 2026 05:13 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mnvxaabkzs2ahttps://bsky.app/profile/planetplanet.bsky.social/post/3mmjih2s4cs2m@elizabethtasker.bsky.social made an amazing and amazingly clear all about sample return mission from asteroids. Well worth your time! [contains quote post or other embedded content]23 May 2026 12:51 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mmjih2s4cs2mhttps://bsky.app/profile/planetplanet.bsky.social/post/3mmbj55xqp22fI love this new paper about planets in AGN disks around supermassive black holes! arxiv.org/abs/2605.19241 Naturally, it also helps to motivate some of the crazy planetary systems I've built: https://planetplanet.net/2018/06/01/the-million-earth-solar-system/ https://arxiv.org/abs/2605.1924120 May 2026 08:42 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mmbj55xqp22fhttps://bsky.app/profile/planetplanet.bsky.social/post/3mdnopkbtpc2aIt'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! [contains quote post or other embedded content]30 Jan 2026 16:07 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mdnopkbtpc2ahttps://bsky.app/profile/planetplanet.bsky.social/post/3mal7w6jqws2kMy 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%). https://ui.adsabs.harvard.edu/abs/2025arXiv251207979R/abstract22 Dec 2025 12:21 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3mal7w6jqws2khttps://bsky.app/profile/planetplanet.bsky.social/post/3m7xs22tnh22vLast 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!) https://planetplanet.net/2025/12/13/black-hole-sun/14 Dec 2025 18:52 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m7xs22tnh22vhttps://bsky.app/profile/planetplanet.bsky.social/post/3m6pdtvf7bc25About 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!28 Nov 2025 16:52 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m6pdtvf7bc25https://bsky.app/profile/planetplanet.bsky.social/post/3m5vmpkeg3k2wIf 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. https://www.francetvpro.fr/contenu-de-presse/74631584 https://france.tv18 Nov 2025 11:21 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m5vmpkeg3k2whttps://bsky.app/profile/planetplanet.bsky.social/post/3m522etf7sk2xI 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 https://www.amazon.com/dp/B08LFZZWGZ07 Nov 2025 12:11 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m522etf7sk2xhttps://bsky.app/profile/planetplanet.bsky.social/post/3m3kkxpcdls2uHere'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. https://nautil.us/could-the-suns-orbit-shape-evolution-124218619 Oct 2025 15:00 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m3kkxpcdls2uhttps://bsky.app/profile/planetplanet.bsky.social/post/3m3kkvfc5ek2uhttps://nautil.us/the-nautilus-reading-list-about-the-cosmos-1241638/19 Oct 2025 14:59 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m3kkvfc5ek2uhttps://bsky.app/profile/planetplanet.bsky.social/post/3m2tsv2ruis2vNew 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) https://planetplanet.net/2017/05/03/the-ultimate-engineered-solar-system/10 Oct 2025 13:51 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3m2tsv2ruis2vhttps://bsky.app/profile/planetplanet.bsky.social/post/3lyfakubjek2aIn 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) https://nautil.us/wild-orbits-prime-planets-for-life-1231853/09 Sep 2025 07:55 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3lyfakubjek2ahttps://bsky.app/profile/planetplanet.bsky.social/post/3lxv23towx22kHere'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? https://planetplanet.net/2025/09/02/eccentric-rings-of-co-orbital-planets/02 Sep 2025 21:17 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3lxv23towx22khttps://bsky.app/profile/planetplanet.bsky.social/post/3lxkdcrafuk2gFlashback to 2012 when I ate the Sun (Photo from the top of Vulcano in Sicily)29 Aug 2025 15:03 +0000at://did:plc:yem4aneptdbzpgwhf7qaocwp/app.bsky.feed.post/3lxkdcrafuk2g