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Sean Carroll

@seanmcarroll.bsky.social

38K followers 580 following 7.9K posts

Physics, philosophy, complexity. @jhuartssciences.bsky.social & @sfiscience.bsky.social. Host, #MindscapePodcast. Married to @jenlucpiquant.bsky.social. Latest books: The Biggest Ideas in the Universe. https://preposterousuniverse.com/

preposterousuniverse.com

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Sean Carroll @seanmcarroll.bsky.social · Sep 5

Postdoc job! I expect to have an opening at Johns Hopkins for a postdoctoral researcher working somewhere in the broad realms of physics, philosophy, and complexity. Apply at Academic Jobs Online:

academicjobsonline.org/ajo/jobs/30496

Johns Hopkins University, Physics and Astronomy

Job #AJO30496, Postdoctoral Fellow in Foundations of Physics, Complexity, and Emergence, Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland, US

academicjobsonline.org

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Sean Carroll @seanmcarroll.bsky.social · 7h

I wonder whether at some point people who are currently Christian nationalists are going to figure out that Christianity isn’t actually a good fit for their core values - too much empathy, helping the downtrodden, etc - and just become pagan nationalists or something.

Rich Raho @richraho.bsky.social · 1d

Pope to Chicago Labor Leaders: “Please know of my appreciation for your welcome of immigrants and refugees, especially your support of food pantries and shelters….I encourage you to continue to advocate for society to respect the human dignity of the most vulnerable.” www.vatican.va/content/leo-...

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Jacob T. Levy @jacobtlevy.bsky.social · 8h

The deportation order derives from the crime of which he has now been exonerated.

www.miamiherald.com/news/local/i...

He was wrongfully imprisoned for 43 years. Moments after being released, ICE took him

Subramanyam “Subu” Vedam now faces deportation.

www.miamiherald.com

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Adrienne Mayor @amayor.bsky.social · 1d

Let me know in a message if you would like a free Spotify code for my audiobook Mythopedia, limited supply

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Sean Carroll @seanmcarroll.bsky.social · 2d

This has made my day.

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Sean Carroll @seanmcarroll.bsky.social · 2d

Tragedy is when I am criticized on social media. Comedy is when you are dismembered with a bone saw and die.

Wajahat Ali @wajali.bsky.social · 2d

With receipts!

www.theguardian.com/stage/2025/o...

‘Amoral, evil’: vitriolic backlash builds against comics who played Riyadh festival

Murder by bone-saw, lashings for rape victims, punishment amputation, jail for satirists … these are the Saudi human rights abuses fuelling the fury being directed at the likes of Louis CK, Dave Chapp...

www.theguardian.com

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Senator Chris Van Hollen @vanhollen.senate.gov · 2d

This is what courage in the face of authoritarianism looks like. No university should take Trump's bribe & surrender their integrity — bending the knee to a bully only feeds the beast & puts ALL our rights at risk.

Others should follows MIT’s example ASAP.

MIT rejects Trump administration deal for priority federal funding

MIT is one of the nine schools that were asked to agree to adopt conservative priorities and policies in exchange for funding perks.

www.washingtonpost.com

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Filipe Campante @filipecampante.bsky.social · 2d

It might be hard to convey to people outside economics just how seismic this is. The Trump effect has most certainly arrived to US academia.

Florian Scheuer @florianscheuer.bsky.social · 2d

I am delighted to share that Nobel laureates Esther Duflo and Abhijit Banerjee will join our Department of Economics @econ.uzh.ch at the University of Zurich on July 1, 2026, as Lemann Foundation Professors of Economics.

🧵 1/7

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Sean Carroll @seanmcarroll.bsky.social · 2d

Still can’t get over that my job involves talking and thinking about this stuff.

Sean Carroll @seanmcarroll.bsky.social · 2d

The fun, of course, is thinking about the implications, from the Einstein-Podolsky-Rosen (EPR) paper from 1935. If we move spins A and B far apart, it remains true that the outcome of Alice measuring her spin affects the potentialities for Bob's measurement outcomes. Spooky action at a distance!

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Sean Carroll @seanmcarroll.bsky.social · 2d

How can spin B's options be affected by A's measurement, apparently faster than light? And how does Nature conspire to prohibit us from using this fact to actually send information?

I was honest that people still don't agree on how to talk about this. A modern intellectual tragedy.

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Sean Carroll @seanmcarroll.bsky.social · 2d

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Sean Carroll @seanmcarroll.bsky.social · 2d

Another fun lecture today, this time in #QM1. It didn't start out fun, at least not any more fun than usual: we considered measurements on composite (possibly entangled) systems. Did an example of two entangled spins and showed how to calculate probabilities and how wave functions collapse.

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Jennifer Ouellette @jenlucpiquant.bsky.social · 3d

How Easter Island’s giant statues “walked” to their final platforms. It's basic pendulum physics, per new study. Workers with ropes could make the moai "walk" in zig-zag motion along roads tailor-made for the purpose. arstechnica.com/science/2025...

How Easter Island’s giant statues “walked” to their final platforms

Workers with ropes could make the moai “walk” in zig-zag motion along roads tailor-made for the purpose.

arstechnica.com

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Sean Carroll @seanmcarroll.bsky.social · 2d

If anyone wants the full story, do I have the book for you.

www.amazon.com/Eternity-Her...

From Eternity to Here: The Quest for the Ultimate Theory of Time

Buy From Eternity to Here: The Quest for the Ultimate Theory of Time on Amazon.com ✓ FREE SHIPPING on qualified orders

www.amazon.com

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Sean Carroll @seanmcarroll.bsky.social · 2d

Another was to imagine an eternal universe with random thermal fluctuations. Wait long enough and you will fluctuate into whatever low-entropy condition you like.

In doing so he invented (1) the multiverse and (2) the anthropic principle. Clever! But as we shall see it doesn’t quite work…

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Sean Carroll @seanmcarroll.bsky.social · 2d

One was to imagine that the universe “started” in a low entropy state. That’s actually what we currently think is the right answer! But Boltzmann is writing in a Newtonian world, 20 years before general relativity. He had a chance to basically invent the Big Bang, but never really followed up.

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Sean Carroll @seanmcarroll.bsky.social · 2d

The basic problem is that you can’t really derive a time-asymmetric conclusion from purely time-symmetric assumptions. In an 1895 paper, Boltzmann insisted this issue was easily overcome— but offered multiple ways to do it, which were mutually incompatible.

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Sean Carroll @seanmcarroll.bsky.social · 2d

Today in #PhilosophyOfCosmology was one of my favorite topics: Boltzmann’s justification(s) for the Second Law, especially in response to Lohschmidt’s Reversibility Objection and Zermelo’s Recurrence Objection. Boltzmann was both incredibly clever and somewhat shifty!

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okay Kelly @kmdoublev.bsky.social · 2d

Making sure my slide deck template matches the vibe of my outfit. Is this the digital humanities?

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John Rogers @johnrogers.bsky.social · 3d

ME: Now Mom, just remember, there's a lot of disinformation and AI in your social feed and your friends' Facebook.
MOM: I know! My friend sent me this crazy post where someone used AI to make an image of a giant frog fighting Army troops!
ME: ... okay, no, that one's ... goddamit, Portland.

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Carl Zimmer @carlzimmer.com · 3d

Today my @nytimes.com colleagues and I are launching a new series called Lost Science. We interview US scientists who can no longer discover something new about our world, thanks to this year‘s cuts. Here is my first interview with a scientist who studied bees and fires. Gift link: nyti.ms/3IWXbiE

nyti.ms

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Sean Carroll @seanmcarroll.bsky.social · 4d

Wait until I tell you all the people who won awards *before* appearing! I'm claiming credit for those too.

Sean Carroll @seanmcarroll.bsky.social · 4d

This adds the MacArthur to the Oscar and Nobel as prestigious awards that people have won after appearing on my podcast. #MindscapePodcast gets results!

www.preposterousuniverse.com/podcast/2024...

Title card for Mindscape episode with Hahrie Han.

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Sean Carroll @seanmcarroll.bsky.social · 4d

Congrats to my friend and Hopkins colleague Hahrie Han for being selected as one of this year's MacArthur Fellows!

www.macfound.org/programs/awa...

MacArthur Fellows - MacArthur Foundation

The MacArthur Foundation supports creative people and effective institutions committed to building a more just, verdant, and peaceful world. In addition to selecting the MacArthur Fellows, we work to ...

www.macfound.org

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Sean Carroll @seanmcarroll.bsky.social · 4d

Trump’s enablers in govt/media honestly think of him as a ranty old gasbag, so they don’t treat authoritarian pronouncements like this seriously.

They should! Have they learned nothing?

Governor JB Pritzker @govpritzker.illinois.gov · 4d

I will not back down.

Trump is now calling for the arrest of elected representatives checking his power.

What else is left on the path to full-blown authoritarianism?

Donald Trump Truth Social Post: Chicago Mayor should be in jail for failing to protect Ice Officers! Governor Pritzker also.

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Sarah Kendrew @sarahkendrew.bsky.social · 4d

Reading this thread and thinking how incredibly useful it is to be able to sit down and have a smart grown up tell me what I need to know about a topic I'm interested in. I know a PhD is supposed to prep us for this, but it's hard. 🧪🔭

Sean Carroll @seanmcarroll.bsky.social · Aug 25

First day of classes at @jhuartssciences.bsky.social. A glorious day to learn #QuantumMechanics!

I'm teaching two courses - QM for physics majors, and Philosophy of Cosmology for a general audience. I'm going to try to maintain a thread saying what happens in each class, let's see how I do.

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