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A more diplomatic and uncontroversial way to put it is that the event horizon is the only thing we have any evidence for.
by uoaei 2y ago
A more diplomatic and uncontroversial way to put it is that the event horizon is the only thing we have any evidence for.
- oneshtein 2y agoTwo event horizons, because gravitation cancels out in the center of a black hole. ps. Energy is sucked up from the center by second event horizon, but matter is pushed inside, forming a dense and cool crystal, a solid foundation for second order effects to play.
- uoaei 2y agoThat assumes there is gravity, or even universe, "inside" the black hole. We don't have any evidence of that.
- oneshtein 2y agoOccam's razor says that you must present a proof that they are not existing in a black hole.
- JumpCrisscross 2y ago> Occam's razor says that you must present a proof that they are not existing in a black hole Occam’s razor absolutely doesn’t predict that the weird thing that breaks physics occurs twice and then precipitates a crystal.
- oneshtein 2y agoPhysics is fine, it just model, which breaks. However, we can see that stars are eaten by black holes, and then can be partially released back years later, so it's proven that 1) «an event horizon» exists, 2) matter can pass the «event horizon» in both directions, 3) light cannot pass the «event horizon» in one direction. I do not introduce a new physics, like a «singularity», without any evidence. Occam's razor is in my hands now.
- zardo 2y ago> 2) matter can pass the «event horizon» in both directions Where was this proven?
- mitthrowaway2 2y agoThe comment you're responding to didn't assert that it is proven, but regardless: https://en.wikipedia.org/wiki/Hawking_radiation#Emission_process https://en.wikipedia.org/wiki/Hawking_radiation#Emission_pro...
- JumpCrisscross 2y agoHawking radiation is almost painfully constructed to avoid the problem of anything, even information, crossing back through the event horizon.
- Maxatar 2y agoThe Wikipedia article is fairly loose with language, but at any rate Hawking radiation does not originate past the event horizon itself but just before it.
- mitthrowaway2 2y agoI suppose it's a philosophical matter, but it seems legitimate to me to view this as matter moving out of the event horizon, even if the mechanism of that motion is very indirect. One's answer would depend on whether you consider a photon that travels to your eyes from the sun after reflecting from a mirror to be the same photon that was originally emitted by the sun, because it carries that photon's energy and information, even if it was actually absorbed and then coherently re-emitted by the mirror after a staggeringly complicated sea of particle-particle interactions.
- Maxatar 2y agoOkay in terms of philosophy sure you could maybe make an argument, I don't know. What we can, however, say that is more tangible is that the make-up of Hawking radiation cannot depend whatsoever on the matter that falls into the black hole apart from three properties: mass, charge and momentum. Other than those three properties, all other information that crosses the event horizon is lost and can't escape. So, if one black hole was formed purely from 1 kg of protons with 0 momentum, and another black hole was formed from 1 kg of positrons with 0 momentum, these two black holes would be indistinguishable from each other. There would be nothing that could be emitted by either black hole via Hawking radiation or any other mechanism that could allow you to deduce that one was formed from protons and the other from positrons. It's in this stricter information theoretic sense that nothing escapes from beyond the event horizon of a black hole.
- mr_mitm 2y agoBlack holes are a prediction of general relativity. The same theory predicts that all properties of spacetime exist up until the singularity. You cannot simultaneously believe in black holes and some sort of discontinuation of spacetime before the singularity.
- uoaei 2y agoThat is a theory that makes predictions, not evidence. As you may note in my comments above, I am speaking exclusively to evidence.
- mr_mitm 2y agoIt doesn't make sense to talk about black holes outside the context of GR. What do you even mean by black hole if you can't describe it in the language of GR?
- JumpCrisscross 2y ago> What do you even mean by black hole if you can't describe it in the language of GR? You’re right. But playing devil’s advocate, there are QM objects that look like black holes [1] as well as observations of a supermassive object at Sagittarius A*. [1] https://arxiv.org/html/2307.06164v2 https://arxiv.org/html/2307.06164v2
- uoaei 2y agoThe parts of GR we trust in order to interpret the data from our instruments is trusted precisely because there is evidence to back up those parts of the theory. We have no idea if that theory holds on the other side of a boundary across which no causation can occur.
- mr_mitm 2y agoThe data we have about black holes is nothing more than evidence of objects with a size and density which are only consistent with black holes according to GR. Without assuming GR is true, you have only evidence of unusually dense objects, nothing more.
- GoblinSlayer 2y agoWe don't have evidence for event horizon. Black hole is a hypothetical object to begin with, it exists only in mathematics, what evidence.
- blovescoffee 2y agoThe photos we have of black holes?
- GoblinSlayer 2y agoWe only have photos of collapsars, not black holes. For mathematics the difference is big, only black holes have peculiar mathematical properties.
- devnullbrain 2y agoThat definition requires a higher standard of proof than a Nobel prize committee.
- GoblinSlayer 2y agoA photo of a star is cool, why not give a prize for it. Or maybe they use attention economy. You can't exactly blame them for attention economy, can you?
- devnullbrain 2y agoPhotos as the only evidence of existence are a very convenient way of claming the nonexistence of something that reflects zero light. The baby-out-with-the-bathwater is that it also means there's no proof for anything outside the visible range of light, that's too small to show up on a CCD, or that predates the camera. Or you.
- uoaei 2y agoOn the other hand, arbitrary conjecture in absence of evidence should be treated exactly as such. It's worth noting that there are a number of phenomena for which we have built detectors to find this mysterious "dark matter", all of which have failed to turn anything up whatsoever. In fact they are less than useless in that we still don't know if any of the proposed mechanisms can even be ruled out yet. The experiments achieved basically zero information gain in that regard. Occam's razor flashes bright in the cold dark of space.