Barbara Ryden
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Barbara Ryden
@bsryden.bsky.social
500 followers 370 following 130 posts
Writer of astrophysics textbooks, servant to cats
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bsryden.bsky.social
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
Barbara Ryden (wearing a nametag saying "Barbara Ryden") stands in front of a large sign saying "AAS".
January 8, 2026 at 10:19 PM
bsryden.bsky.social
I haven't quite decided if this is the ideal epigraph for chapter 8. Too Byronic, do you think, or just Byronic enough?
Epigraph for chapter 8 of Astrophysical Gas Dynamics: When Newton saw an apple fall, he found In that slight startle from his contemplation - 'Tis said (for I'll not answer above ground For any sage's creed or calculation) - A mode of proving that the earth turn'd round In a most natural whirl, called "gravitation"; And this is the sole mortal who could grapple, Since Adam, with a fall or with an apple. Lord Byron, "Don Juan," Canto X [1823]
January 1, 2026 at 10:17 PM
bsryden.bsky.social
Happy Boxing Day from Finn the cat!
An orange tabby cats sits inside a cardboard box.
December 26, 2025 at 5:29 PM
bsryden.bsky.social
Happy #Solstice! I hope everyone in the northern hemisphere is keeping warm (preferably with the help of a cat).
Orange tabby cat, sitting comfortably on a human lap
December 21, 2025 at 3:03 PM
bsryden.bsky.social
I hope you are having a well-groomed #Caturday (perhaps with a little help from a friend).
A gray and white cat (Trim) licks the head of an orange tabby cat (Finn).
December 13, 2025 at 3:40 PM
bsryden.bsky.social
Happy #Caturday! At this point, my cats' knowledge of physics is starting to catch up with mine.
An orange tabby cat examines the book Physics for Cats, by Tom Gauld.
November 22, 2025 at 11:04 PM
bsryden.bsky.social
#Caturday night.
An orange tabby cat, lying on a human's lap, looks up at the camera.
October 26, 2025 at 12:07 AM
bsryden.bsky.social
Advice from Finn and Trim: get plenty of rest this #Caturday, to prepare you for the week ahead.
Two cats snoozing. Finn (on the left) is burrowed into a comforter; Trim (on the right) is curled up on top of a folded blanket.
October 11, 2025 at 2:58 PM
bsryden.bsky.social
Happy Fat Bear Week to those who celebrate!
Winne the Pooh (after mass consumption of honey and condensed milk) gets wedged in the door of Rabbit's house. Illustration by E. H. Shepard
September 28, 2025 at 7:49 PM
bsryden.bsky.social
I'm not certain this is the best possible epigraph for a chapter on accretion, but I was feeling Rabelaisian when I chose it.
Epigraph for chapter 7 of Astrophysical Gas Dynamics: L'appétit vient en mangeant. (Appetite comes with eating.) François Rabelais Gargantua, book 1, chap. 5 (1534)
September 22, 2025 at 6:32 PM
bsryden.bsky.social
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.
Epigraph to Chapter 6 of Astrophysical Has Dynamics: It was at a meeting of the British Association in London in 1933 that I remember that [Horace] Lamb remarked, "I am an old man now, and when I die and go to Heaven there are two matters on which I hope for enlightenment. One is quantum electrodynamics, and the other is the turbulent motion of fluids. And about the former I am really rather optimistic." Sydney Goldstein
August 17, 2025 at 6:15 PM
bsryden.bsky.social
Happy #Caturday! May you have all the cat hugs you desire.
An orange tabby cat sits on a human's lap and hugs them around the waist.
August 16, 2025 at 6:15 PM
bsryden.bsky.social
Happy #Caturday: may you dream of stars.
Two cats sleeping on a fleecey blanket covered with stars.
July 26, 2025 at 5:08 PM
bsryden.bsky.social
Roundhay Scene (1888)
July 23, 2025 at 11:51 PM
bsryden.bsky.social
For balance, a chapter that contains Maxwell's Equations must start with Maxwell's Poetry.
Epigraph to Chapter 5 (Mangetohydrodynamics): The world may be utterly crazy, And life may be labour in vain; But I'd rather be silly than lazy, and would not quit life for its pain. -- James Clerk Maxwell [1858]
July 14, 2025 at 6:30 PM
bsryden.bsky.social
Remember to take some time to relax this #Caturday (in whatever posture suits your mood).
An orange tabby cat (named Finn) lounges upside down by the front door of a house.
July 5, 2025 at 5:37 PM
bsryden.bsky.social
I continue my cinematic era with the epigraph to Chapter 4 of Astrophysical Gas Dynamics.
The beginning of Chapter 4 ("Advanced Shocks") of Astrophysical Gas Dynamics, to be published in 2026. The epigraph of the chapter is Captain Renault: I am shocked, *shocked*, to find that gambling is going on in here. [Julius Epstein, Philip Epstein, and Howard Koch. Casablanca screenplay, 1942]
June 28, 2025 at 8:20 PM
bsryden.bsky.social
I cannot guarantee that I will stop crabbing. I will try, however, to stop doing it from pontoons.
View from the pier in St Mawes, Cornwall. A sign states, "Sorry no crabbing from pontoon."
May 24, 2025 at 10:30 PM
bsryden.bsky.social
Finn the cat is hanging out with his lobster. Happy #caturday!
Finn (an orange tabby cat) with his lobster-shaped cat toy.
March 29, 2025 at 5:54 PM
bsryden.bsky.social
Given 274 confirmed moons of Saturn, Lucy definitely has a point.
Peanuts cartoon for 1977 Jul 13 panel 1: Lucy, wearing a baseball glove, misses a fly ball. panel 2: Charlie Brown tells Lucy, "There's no excuse for missing a ball like that! There's absolutely no excuse!" panel 3: Lucy responds, "The moons of Saturn got in my eyes!" panel 4: Charlie Brown concedes, "I take it back... That wasn't a bad excuse..."
March 18, 2025 at 3:36 PM
bsryden.bsky.social
I am entering my cinematic era with the epigraph for Chapter 3 of Astrophysical Gas Dynamics.
epigraph for chapter 3 of Astrophysical Gas Dynamics: "In space, no one can hear you scream." [Barbara Solinger Gips, advertising tagline for Alien]
March 15, 2025 at 3:39 PM
bsryden.bsky.social
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.)
Epigraph for Chapter 2 of Astrophysical Gas Dynamics: "When the gap between ideal and real becomes too wide, the system breaks down" Barbara Tuchman (1912-1989) A Distant Mirror, Foreword [1978] Figure 2.1 from Astrophysical Gas Dynamics: panel (a) show Eeyore drifting downstream, panel (b) shows Pooh, Piglet, Roo, and Rabbit watching from a bridge [illustration from The House at Pooh Corner, chapter 6, E. H. Shepard, artist]
February 23, 2025 at 7:34 PM
bsryden.bsky.social
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.
A copy of Celestial and Stellar Dynamics, by Barbara Ryden (part of The Ohio State Astrophysics Series). A teddy bear wearing a sweater with the motto "Density is Destiny!" sits behind the book.
February 6, 2025 at 8:36 PM
bsryden.bsky.social
Opposing fascism and defying gender stereotypes: it's as American as apple pie, the Saturday Evening Post, and Norman Rockwell.
Saturday Evening Post cover, January 2, 1943: a baby (symbolizing the new year) bayonets a swastika. [J. C. Leyendecker, artist] Saturday Evening Post cover, May 29, 1943: Rosie the Riveter eats a sandwich on her lunch break, in front of an American flag. [Norman Rockwell, artist]
February 6, 2025 at 12:26 AM
bsryden.bsky.social
When a polar vortex is on its way, it is important to be prepared.
Finn the cat is snuggled within a folded comforter, with only his head and front legs sticking out.
January 18, 2025 at 4:37 PM