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A) I like cute scroll effects, but maybe we should consider making them additive rather than completely ephemeral (when screen size permits)? The intro is beaut

by bbor 2y ago

A) I like cute scroll effects, but maybe we should consider making them additive rather than completely ephemeral (when screen size permits)? The intro is beautiful on mobile, I'm sure, but it's just kind of irritating on desktop. B) Thanks so much for posting, I had skimmed a few of these articles but didn't realize it was part of a cohesive series. For others, since it's not really obvious at first: the whole series is built to setup the three articles at the bottom, where Charlie Wood examines three competing research groups. Quanta is on fire these days... This is an amazing evolution upon 2020's What is a Particle?, which is an article I've been bringing up in like every other conversation b/c it's so fascinating and accessible. C) Other than the initial complaints about the intro, the article itself is downright groundbreaking webdev-wise. And I called it when I started this comment -- the rest is additive! The way the text deforms around the sliding divs (but quick enough that it probably won't interrupt you since you haven't gotten to it yet) is just beautiful, I don't think I've seen that before. The dynamic, freeform cutouts fit perfectly with the theme, and the background is bold (how many sites are purple??) but indescribably perfect. Of course, the star of the show is the animated "thought experiment" page, even if the transitions are atomic (can't be reversed halfway through by scrolling back up). And the final summary + animation is worth scrolling to the bottom for, even if you don't read the rest of it. Well done Quanta web team, you're seriously raising the bar with this article, IMHO. Inspiring stuff. Is there any magazine ~~article~~ "series" (issue?) that even approaches the beauty and cohesiveness of this one? I'd love to proven wrong by the experts on here ;) [ETA: wow everyone hates the UX, I'm shocked. Why, in particular...? At the end of the day the linked page is just a list of links that appears right near the top, I don't understand the ubiquitous hate! What am I missing?] D) I'm pretty far from critically evaluating the physics surveys themselves, but I certainly found them helpful. Some quotes that are just insanely insightful, the kind of simple, boring statements that edge on superstition through their pure profundity alone: In periods when we are looking for new theories, physics has always become philosophical. Our natural perspective as beings with locations separated by space sticks out as a mathematical oddity. “It’s a reminder that the laws of physics that we perceive in our world don’t seem to be random,” said Sean Carroll (opens a new tab), a physicist at Johns Hopkins University. “They seem to be specific.” “AdS/CFT is an insane suggestion that should be stupid,” said Geoff Penington, a physicist at the University of California, Berkeley who studies holography. “But then you try all these things, and it all ends up being consistent.” For his part, he feels that holography isn’t radical enough. It shows how one dimension of space could emerge, but otherwise all the familiar ingredients of quantum theory are there from the start: some space, locality, and a clock to mark time. Arkani-Hamed feels that all of those elements should emerge together from something more primitive — as they do in surfaceology. It might seem like I’m interested in lots of different things, but I’m not sure if they’re really all that disconnected. At least within math, it is kind of true that sufficiently beautiful things tend to be connected with one another. E) Any friendly experts around to explain what a "lower dimension" representation of a black hole would look like? What's a periodically-repeating 2D manifold, given that circles (flattened spheres) don't pack? I guess it warps to pack nicely? This is a core example they use to explain the broader thesis--which I thought I understood--but I don't really understand in the topological shape of what they're describing, so it ended up confusing me more. In particular I'm commenting on this: So the key to black holes’ underlying structure exists on their surface. “People began to think,” Law said, “that maybe whatever microscopic theory describes black holes lives in a space-time with one lower dimension.” F) Even more fundamentally, can someone explain why we can't just assume that there isn't spacetime inside black holes? If everything's pointing towards their contents being entirely contained within their infinitely-thin surface, why can't we just embrace that? In other words, that whatever determinations make up the universe are undetermined in those places? That the diameter of every black hole is 0, when considered from the inside? I'm assuming the answer is "complicated math says no", but I'm failing to confirm that. Sorry for the spam, won't mind if this is deleted -- it's just terribly helpful to write as I go. If you're scrolling by, I highly recommend bookmarking this series in full! And if you work at Quanta and are reading this: you're awesome.

jiggawatts 2y ago
> F) Even more fundamentally, can someone explain why we can't just assume that there isn't spacetime inside black holes? If everything's pointing towards their contents being entirely contained within their infinitely-thin surface, why can't we just embrace that? You're not crazy, that's my pet theory too!
mr_mitm 2y ago
> F) Even more fundamentally, can someone explain why we can't just assume that there isn't spacetime inside black holes? If everything's pointing towards their contents being entirely contained within their infinitely-thin surface, why can't we just embrace that? It's not that simple. The surface at the event horizon is not a physical thing, it's a coordinate singularity which is only apparent for a very distant observer. If you imagine two spaceships flying towards the center of a black hole within close distance, they would notice nothing unusual when crossing the event horizon. They would be in constant radio contact. It's mind bending stuff, really.
- raattgift 2y ago
  The idea of making the black hole membrane paradigm generally covariant and everywhere locally Lorentz invariant gives me a migraine. Dropping charges onto a superthin surface (and keeping it cold, we have to consider arbitrarily large SMBHs too) or having the superthin surface emit Hawking radiation is hard to make not-a-toy (step 0: spectral structure evolution; step 1: ultraboost something, Aichelburg-Sexl style pancake; step 2: astronomer near ISCO around a distant SMBH; step 3: Rindler particles from the membrane's pole; step 4: incoming ultra-high-energy cosmic rays, GZK-like cutoff induced above membrane; ...; step N how the hell do they evolve during the PN phase of a BHB merger, and how do you match that up with the numerical relativity?). (This line of thought has taken me somewhere that seems crazy: following Giddings & Rychkov <https://arxiv.org/abs/hep-th/0409131v1 https://arxiv.org/abs/hep-th/0409131v1> and Yoshino & Mann (RN metric and during the LHC-will-destroy-the-world silliness) <https://arxiv.org/abs/gr-qc/0605131v3 https://arxiv.org/abs/gr-qc/0605131v3> can UEHCRs on a hyperbolic orbit peel off small black holes from the electromagnetic field around a black hole membrane? If a standard quiescent BH is massive enough there won't be much Hawking anything to collide with, so we won't see evaporation signals; but isn't there a nontrivial electromagnetic field strength close to even a big horizon in the membrane paradigm or anything reasonably like it? [note to self, in case I care later: Parikh & Wilczek (1997) "An Action for Black Hole Membranes" <https://arxiv.org/abs/gr-qc/9712077 https://arxiv.org/abs/gr-qc/9712077> just after eqn. (3.8)])

by bbor 2y ago

jiggawatts 2y ago

mr_mitm 2y ago

> F) Even more fundamentally, can someone explain why we can't just assume that there isn't spacetime inside black holes? If everything's pointing towards their contents being entirely contained within their infinitely-thin surface, why can't we just embrace that? It's not that simple. The surface at the event horizon is not a physical thing, it's a coordinate singularity which is only apparent for a very distant observer. If you imagine two spaceships flying towards the center of a black hole within close distance, they would notice nothing unusual when crossing the event horizon. They would be in constant radio contact. It's mind bending stuff, really.

raattgift 2y ago
The idea of making the black hole membrane paradigm generally covariant and everywhere locally Lorentz invariant gives me a migraine. Dropping charges onto a superthin surface (and keeping it cold, we have to consider arbitrarily large SMBHs too) or having the superthin surface emit Hawking radiation is hard to make not-a-toy (step 0: spectral structure evolution; step 1: ultraboost something, Aichelburg-Sexl style pancake; step 2: astronomer near ISCO around a distant SMBH; step 3: Rindler particles from the membrane's pole; step 4: incoming ultra-high-energy cosmic rays, GZK-like cutoff induced above membrane; ...; step N how the hell do they evolve during the PN phase of a BHB merger, and how do you match that up with the numerical relativity?). (This line of thought has taken me somewhere that seems crazy: following Giddings & Rychkov <https://arxiv.org/abs/hep-th/0409131v1 https://arxiv.org/abs/hep-th/0409131v1> and Yoshino & Mann (RN metric and during the LHC-will-destroy-the-world silliness) <https://arxiv.org/abs/gr-qc/0605131v3 https://arxiv.org/abs/gr-qc/0605131v3> can UEHCRs on a hyperbolic orbit peel off small black holes from the electromagnetic field around a black hole membrane? If a standard quiescent BH is massive enough there won't be much Hawking anything to collide with, so we won't see evaporation signals; but isn't there a nontrivial electromagnetic field strength close to even a big horizon in the membrane paradigm or anything reasonably like it? [note to self, in case I care later: Parikh & Wilczek (1997) "An Action for Black Hole Membranes" <https://arxiv.org/abs/gr-qc/9712077 https://arxiv.org/abs/gr-qc/9712077> just after eqn. (3.8)])