Since the cats have anti-parallel spins, they can both occupy the ground state. (Since they are cats, they are seldom in an excited state.)

Seen from certain angles, at occasional moments, the OSU campus is lovely.

Trim and Finn are recovering after their Caturday night party.

@benneholwerda.bsky.social is an authority. Pay attention to their words of wisdom!

Apparently, I am an author. It says so, right on my label.

Although my Friday lecture was on quasars, I decided to spread some Moon joy in the cover slide for the lecture. (The students seemed to tolerate the digression.)

"I'd like to get away from Earth awhile And then come back to it and begin over." For some reason, Robert Frost keeps running through my head today....

Now 285.

Happy #Caturday! Trim and Finn have each others' back, in a fine example of feline solidarity.

Finally... some "introverted astronomer" representation in the media!

Happy #Caturday. If you are in the path of a winter storm, Trim and Finn recommend that you keep warm.

Stellar Structure and Evolution: a very fine textbook.

It is not strictly required, when attending a meeting of the American Astronomical Society, to pose in front of the big AAS sign. However, I couldn't resist the opportunity. #aas247

I haven't quite decided if this is the ideal epigraph for chapter 8. Too Byronic, do you think, or just Byronic enough?

Happy Boxing Day from Finn the cat!

Happy #Solstice! I hope everyone in the northern hemisphere is keeping warm (preferably with the help of a cat).

I hope you are having a well-groomed #Caturday (perhaps with a little help from a friend).

Happy #Caturday! At this point, my cats' knowledge of physics is starting to catch up with mine.

#Caturday night.

Advice from Finn and Trim: get plenty of rest this #Caturday, to prepare you for the week ahead.

Happy Fat Bear Week to those who celebrate!

I'm not certain this is the best possible epigraph for a chapter on accretion, but I was feeling Rabelaisian when I chose it.

Although a quotation about the incomprehensibility of turbulence (even with divine intervention) is often attributed to Werner Heisenberg, this statement by Horace Lamb seems to have priority.

Happy #Caturday! May you have all the cat hugs you desire.

Happy #Caturday: may you dream of stars.

Roundhay Scene (1888)

For balance, a chapter that contains Maxwell's Equations must start with Maxwell's Poetry.

Remember to take some time to relax this #Caturday (in whatever posture suits your mood).

I continue my cinematic era with the epigraph to Chapter 4 of Astrophysical Gas Dynamics.

I cannot guarantee that I will stop crabbing. I will try, however, to stop doing it from pontoons.

Finn the cat is hanging out with his lobster. Happy #caturday!

Given 274 confirmed moons of Saturn, Lucy definitely has a point.

I am entering my cinematic era with the epigraph for Chapter 3 of Astrophysical Gas Dynamics.

I have chosen an epigraph for Chapter 2, and I think I have found a good illustration for the difference between Lagrangian and Eulerian observers. (I still have to negotiate the rights from the Shepard Trust, however.)

The latest volume in The Ohio State Astrophysics Series has been published! Thanks go to everyone in The Ohio State Astronomy Department, but especially to the students in the graduate dynamics class.

Opposing fascism and defying gender stereotypes: it's as American as apple pie, the Saturday Evening Post, and Norman Rockwell.

When a polar vortex is on its way, it is important to be prepared.

Are you attending #aas245? Stop by the Cambridge University Press display and get 30% off their featured books (including my latest, Celestial and Stellar Dynamics). Not attending? You can still get the discount online.

This is the time of year when I always think of the Ogden Nash poem "Good Riddance, But Now What?" It ends with the couplet: Hark! It's midnight, children dear. Duck! Here comes another year. (I am preparing to duck 2025.)

With Christmas lunch, there is nothing like a snowman-shaped glass filled with Guinness. ("I didn't say there was nothing better. I said there was nothing like it.")

Progress! I have chosen the epigraph for the first chapter of my next book (Astrophysical Gas Dynamics, to be published in 2026). May I have a cookie now?

Best Caturday wishes. I hope you are able to spend some time hanging out with your buddies.

The two people on the right when the clip begins are LePrince's parents-in-law, who were both born in 1816. Yes, there exists video footage of people born during the reign of George III.

What's your favorite 80's movie? Mine is the Roundhay Garden Scene (Louis LePrince, director: October 1888)

Happy caturday! I hope you find time to relax like a cat.

Best barrow ever!

I have two certificates with my name on them, written in Latin (a language I cannot read). Apparently they say I earned a PhD in "rerum astrophysicarum" and made the pilgrimage to Santiago, but I'm not *entirely* certain... [Just in case, I won't read them out loud while standing in a pentagram.]

Are you an undergraduate, grad student, postdoc, professor, or researcher interested in learning more about astrochemistry? Consider applying to the online Global Astrochemistry Lecture Series! The lecturers are world-class astrochemists (plus a cosmologist cunningly disguised in a lab coat).

More Herscheliana to share: a portrait of Caroline Herschel from her obituary in the Illustrated London News, 1848 Jan 29. Her obituary notes “she searched the heavens for comets, and that so effectively as on no less than eight several occasions to be rewarded by their discovery.”

Among my collection of Herscheliana is a Wedgwood jasperware portrait of William Herschel, with Saturn and Georgium Sidus orbiting above. (What’s your favorite portrait of an astronomer?)