Nick @internic@qoto.org
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Theoretical physicist by training (PhD in quantum open systems/quantum information), University lecturer for a bit, and currently paying the bills as an engineer working in optical communication (implementation) and quantum communication (concepts), though still pursuing a little science on the side. I'm interested in physics and math, of course, but I enjoy learning about really any area of science, philosophy, and many other academic areas as well. My biggest other interest is hiking and generally being out in nature.
Joined Nov 2022
@j_bertolotti @BartoszMilewski Right. The situation with your arm is different, and that's where the conformal diagram that @johncarlosbaez posted is helpful. If you imagine an extended object falling into the black hole you can see that light from the left side (closer to the center) will always reach the right side at a later time. If, however, the object stops falling inward while partially over the horizon, light from the portion inside the horizon will never reach the portion outside (correspondingly meaning no causal force law can possibly keep them from tearing apart).
I think that another way to think of it is that near the horizon light is moving outward from the center more and more slowly (in terms of Schwarzschild coordinate distance vs. coordinate time), at the horizon it's standing still, and inside the horizon it's actually falling inward. If you're stationary outside the event horizon, the light from inside never reaches you. If you're falling inward, you will catch up with with the light from stuff further toward the center, because while it is falling toward the singularity, it is doing so more slowly than you (or any massive body).
@BartoszMilewski @johncarlosbaez Incidentally, that video is the work of @SchnittGetsReal
@johncarlosbaez Yeah, but perhaps a sloppy one. Just associating adjoints, duals, and one-forms on a manifold (as a common example of a dual space).
@johncarlosbaez I can only hope that the application for Adjoint School is one form.
Nick
boosted
Hey, don't forget: the deadline to apply to the Adjoint School is December 1st!
This is a great thing to do if you're interested in using category theory to tackle problems in topics like quantum computation, machine learning, numerical analysis or graph theory.
Many applied category theorists I know have gotten their start at this school. You’ll work online on a research project with a mentor and a team of other students for several months. Then you’ll get together for several days at the end of May at the University of Florida, in Gainesville. Then comes the big annual conference on applied category theory, ACT2025.
You can apply here now:
https://adjointschool.com/apply.html
For more details, including the list of mentors and their research projects, go here:
https://adjointschool.com/2025.html
Important dates:
• Application opens: November 1, 2024
• Application deadline: December 1, 2024
• School runs: January-May, 2025
• Research week dates: May 26-30, 2025
Who should apply?
Anyone, from anywhere in the world, who is interested in applying category-theoretic methods to problems outside of pure mathematics. This is emphatically not restricted to math students, but one should be comfortable working with mathematics. Knowledge of basic category-theoretic language—the definition of monoidal category for example—is encouraged.
The school will consider advanced undergraduates, PhD students, post-docs, as well as people working outside of academia. Members of groups which are underrepresented in the mathematics and computer science communities are especially encouraged to apply.
@polotek Maybe I don't know enough about the governance of open source projects, but isn't this a fairly common situation? (Which isn't to say it's not a problem.)
Nick
boosted
One of the worst misfeatures of #Mastodon from a safety angle: If you get an abusive reply to your post, you can't remove it even by blocking the person. Even after blocking, your server still shows the abusive reply to everyone else.
There has been a patch ready to fix this for 2 years, 6 months, and 1 day. @Gargron has not approved it, and has provided *zero* explanation for why he will not allow it to be merged.
@nixCraft A @frameworkcomputer laptop is also a very good alternative.
@johncarlosbaez But presumably @BartoszMilewski's statement that "you'd see the horizon as a black surface coming at you" is true at some level, because what you see in the distance is not only a function of local spacetime (unless you're inside an enclosure, which is the usual conceit of equivalence principle thought experiments).
Nick
boosted
As you're freely falling through the air you don't feel any force except the wind - but you're also getting *stretched* a tiny amount because gravity is a bit stronger near your feet. This is called a 'tidal force' because it creates tides: for example, water on the side of the Earth facing the Moon is pulled toward the Moon more than water on the opposite side.
As a star falls toward a black hole it can get stretched and even destroyed by this tidal force - we've seen it happen! It can create a huge flare of radiation.
But surprisingly, the bigger the black hole, the smaller the tidal force is near the event horizon. We could be falling through the event horizon of a truly enormous black hole right now, and we'd never notice - though I consider this very unlikely.
More importantly, a star like the Sun will only get disrupted *before* it crosses the event horizon if the black hole is < 100 million solar masses. Otherwise it will get sucked in and be lost to sight without any drama!
The big black hole in the center of our galaxy is only 4 million solar masses, so this 'silent death' doesn't happen here. But it happens elsewhere. The biggest black hole known is 66 *billion* solar masses!
Black holes emit flares of light that we don't understand. Some must be from stars falling in. But many flares show very little light in hydrogen's spectral lines! This talk is pretty fun, and it's all about these mysteries.
Nick
boosted
On SciComm.xyz, we have a rule about the use of image description; there are good reasons for that.
The most important one is because we believe that people using screen-readers (or with sight-related problems) should be 1st-class citizens on the Fediverse and should not feel excluded by inaccessible content.
But there are also very down-to-earth reasons why scientists and science communicators should use image descriptions.
A thread.
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- Pronouns
- he/him/his
Theoretical physicist by training (PhD in quantum open systems/quantum information), University lecturer for a bit, and currently paying the bills as an engineer working in optical communication (implementation) and quantum communication (concepts), though still pursuing a little science on the side. I'm interested in physics and math, of course, but I enjoy learning about really any area of science, philosophy, and many other academic areas as well. My biggest other interest is hiking and generally being out in nature.
Joined Nov 2022
