Viewing profile — Keysh

The face-on galaxy image is credited to Stefan Payne-Wardenaar ( https://stefanpw.myportfolio.com/home ), whose Twitter and Bluesky bios say, "I make astronomy visualizations in Bl…

> is there some sort of gravitational body in the middle that makes everything orbit in galaxies? No. The Sun's orbit is determined by the total mass of stars, gas, and dark matter…

I think there is some, but it’s pretty limited. E.g., “He was an old man [who fished alone in a skiff in the Gulf Stream] and …”

"Keplerian" is a term of art based on the rotation curve in Newtonian gravity when all the mass of a system is concentrated at its center. For the Solar System, the rotation curve …

It's kind of amusing that you present "keplerian rotation curves" as a "prediction" of MOND, given that the whole point of MOND is a kludge to produce non -Keplerian rotation curve…

The "batting average" is a bit higher than that. For example, measurements of the proper motion (motion across the sky) of Sirius led to the prediction in 1844 that it was in an or…

You don't need a simulation; you just need an understanding of Newtonian gravity, basic algebra and a bit of calculus, and some knowledge of stellar masses, velocities, and space d…

The problem isn't so much the flatness of the rotation curve, but its continued high value: as you go farther and farther out in distance, it should drop rapidly because most of th…

I think "if the training pool is large enough" is a real issue here. We're not talking about living languages with large, properly attested and annotated corpuses. Indeed, one of t…

It sounds like they were excavated in 1881-1882 (e.g., https://en.wikipedia.org/wiki/Sippar#Archaeology ) by Hormuzd Rassam ("widely believed to be the first-known Middle Eastern a…

> there could be empty regions of space in which billions of years more have elapsed than in e.g. a galaxy. A problem with that idea would be that the ages of galaxies in low-densi…

> There have been a longstanding problem that the history of the universe and cosmological distance scale haven't made sense. https://medium.com/starts-with-a-bang/the-hubble-tensi…

I like how the arXiv sub-category this paper is in is "Soft Condensed Matter". Because of course it is. (Also, the Acknowledgments ends with "We further thank [list of names] for t…

I'll admit I've never seen "track" used to mean "write" before.

> * I'd like to move the cursor backwards and forwards in long commands easier, maybe even with the mouse (!). Use case is, say, a long curl command and I press up-arrow to repeat …

From Chapter VII of Thomas Kuhn, The Structure of Scientific Revolutions ( https://www.lri.fr/~mbl/Stanford/CS477/papers/Kuhn-SSR-2ndEd... ): "If awareness of anomaly plays a role …

Physics has obviously had Kuhnian revolutions since Newton, the emergence of relativity and quantum mechanics being two obvious examples.

The Wikipedia entry includes notes on the hypothesized history of modifications to the disk. For example, the non-solar arcs were probably added later (different gold). So the orig…

Not only that, Saxony-Anhalt filed a recent DMCA takedown notice against Wikimedia ( https://en.wikipedia.org/wiki/Nebra_sky_disc ): > In 2023, the state of Saxony-Anhalt filed a D…

Tardigrades are not "extremophiles", which refers to organisms that live (grow, reproduce) in "extreme" environments ("phile" = "like, love"). Tardigrades can temporarily survive s…

Those would be "captive" ferrets, not "domesticated" ones. (They want to introduce the offspring from the breeding program into the wild, and have in fact done this for about 10,00…

From the linked Washington Post story: "The cloned animals were made by injecting one of Willa’s cells into an egg from a domesticated ferret." Which is kind of interesting, becaus…

The article says that it was no longer functional (in its communications abilities, at least) by that point > Launched in 1969 ... the spacecraft ceased working a few years later .…

The Tines in Vernor Vinge's A Fire Upon the Deep are pretty good example. (The aliens in A Deepness in the Sky are physically alien, but psychologically pretty close to humans.)

Amusingly, I have made three tries to read that book, and kept giving up (getting a little further each time). Partly it was the peculiar sense of aesthetics (e.g., the idea that o…