Breaking Physics more than Black Holes? - Nuclear Engineer Reacts to Kurzgesagt

[ascohn]

"Hopefully, nobody's drawing a vacuum on your room." Literally the nicest thing anyone has said to me this week.

[LetsbeHonestOfficial]

I look at this as a healthy amount of criticism, but with the lack of the meaning of the channel Kurzgesagt = In a nutshell. Their whole point is to take it with a pinch of salt, and to listen to their wording and context carefully, because they do an incredible amount of research for each video compared to other channels, and even correct themselves in the future if they've felt they've done something wrong. With full transparency, authenticity, and hard work. This is simply a theory in its basics for us common folk, and the first source of information I've gotten on gravastars, in which I'm happy for.

[Merennulli]

It's not an issue of calibration. The star's matter is compressing (same as a black hole) with as much gravitational pressure as is possible, while the internal energy pressure has a hard upper limit. This is analogous to electron degeneracy pressure in a neutron star, but with no upper bound where it gets overcome. A point at which it can't be compressed any further, no matter how hard you push. So once a star's mass goes past that threshold, any amount of mass is going to have the same effect.

As for the new form of matter, it's not part of the standard model because it's not defined by a field. It's a boundary layer at the transition between matter as quantum field energy and hyperdense vacuum energy.

[DamianLark]

Actually, the first scientist to speculate about the existence of black holes was John Michell, an English clergyman, natural philosopher, and geologist. In 1784, Michell proposed the idea of what he called "dark stars" in a letter to the Royal Society. Using Newtonian mechanics, he theorized that if a star were massive enough and its gravity strong enough, light would not be able to escape from it.

[fsmvda]

I think the real story is gravastars are a solution to GR equations that do not have a singularity.

The shell is just like maximizing the stress/strain parts of the metric of spacetime. That's why it's not a material it's just an energy configuration in Einstein's equations.

It's an interesting maybe alternative to black holes but it does seem like the evidence is towards black holes not these.

[Xnoob]

The idea i think is that gravastars replace black holes. I mean we know that a singularity is physically impossible by quantum mechanics AFAIK. The thing is, there would not need to be any parking. When a star attempts to collapse into a black hole, the upper limit of density would be reached and it'd automatically stop and form a gravastar.
We currently don't know if the dark mysterious objects in the sky are black holes or gravastars, and we cant tell them apart with our current gravitational wave detectors, but gravastars would be more logical by the singularity issue.
I'm not sure about the other issues gravastars pose though.

[ThisIsNotAUsername-vo]

If I understand the theory correctly (as a non-scientist), the inside of a gravastar would "not have energy" in much the same way the air on a windless day wouldn't have energy. One atmosphere of pressure at sea level is still about 100 kiloNewtons per square meter, but it won't do a thing on its own to turn a windmill. Since the quantum foam would be compressed to its absolute limit in a gravastar, ripples become impossible; the foam can't move. Ho ripples, technically no particles or energy.

It is very theoretical, though. And unless one is detected, it's a math exercise. Forming such a perfect shell also strikes me as highly unlikely.

[bigneto]

Dont they usually put the source material on the description? That can help since the video feels like a massive oversimplification that a concept that is inherently hard.

The vacuum the mention feels a lot like vacuum energy / casimir efect related but thats far above my level of understanding

[fandomguy]

Gravastars don't break physics more than black holes do.

They don't break the second law of thermodynamics. In a closed system entropy must always increase, that's what happens in the core of a Gravistar. "It's made out of Heat Death" which is why it is the coldest object in the universe despite being so massive & full of energy. It's relative, inside all heat gradients are gone, no particles or energy, but outside it's the most massive & energetic object in the universe, hence its gravity. (False Vacuum or "condensed nothing.")

It's similar to how a gas, despite being hotter, higher energy, is actually higher in entropy than a cold solid. Entropy is about disorder, all it cares about, the gravastar's core is maximally disordered, its energy not even organized as particles anymore! Disorder must always increase.

A gravatar is closed off because of its gravity. (Similar to a black hole, energy can't escape.) The video does a bad job of explaining why the gravastar is in equilibrium, it is not inherently because of the shell of adamantine, rather it's the extreme gravity that closes off the core. A gravastar is like a neutron star, it has a crust & a core. Like in a neutron star the crust experiences less forces & thus is made of less exotic material. A neutron star's crust is made of regular atoms, though forced into a strong lattice. The core meanwhile is made of neutron star matter, nuclear pasta, etc. Likewise, a gravastar's crust is made of an "adamantine" state of matter as I call it that is the hardest thing in the universe but less extreme than what's in the core. That's the only reason why it's there.

I suppose it's technically right in that the core feels the weight of the adamantine crust above crushing & sealing it but that's primarily a result of gravity.

[Hd]

8:30 The matter of that thing is constantly compressed to one planck meter (could be useful for a warp ship) and that compression is probably why the matter is what it is. A gapless but very dense, homogenous material with no gaps. It could be as dense as protons or neutrons are but it might be more dense. But for that density calculation, you have to calculate that protons and neutrons have minimal units so you'd have to know how big a neutron or proton is and get that volume to the cool bubble.
It’s not in a particle collider (my guess not a scientific thing lol) because it’s not as compressed and there’s space in all directions. That beyond particle compression is all directions and has to stay compressed (I kinda forgot my original thought on this but this might be it).
8:40 There is probably a correlation between the gravity force and to how densely the vacuum is packed.
10:04 It would just make the vacuum a compressable (relatively resistance free (because we don’t know a place without vacuum)) liquid and give it inherent energy. I am going to guess that vacuum likes to expand but Gravistars don’t expand because the vacuum outside somehow counters it. Maybe because there’s infinite vacuum. It could be an explanation for Gravistars if Hawking Radiation or the effects of it are observed. I have no Idea how that would make sense tho. The Gravistar compresses and the inside vacuum looses energy because it’s already compressed and gets compressed further (think of a metal wire being reformed or a spring loosing mechanical strength) but the outside vaccine close to it can expand and creates a particle for that. Virtual particles would be that vacuum expands but also compresses in other parts which creates a particle-antiparticle pair.
11:43 It's the Gauche limit (I think). Stars are too big for you to reach it because you hit the surface before your tidal forces rip you apart.
14:11 Depends on how the forces of physics are balanced.
14:29 The waves of particles make it imaginable.

[Hd]

So we might be safe from Doofenshmirtz and his two Nickles.

[centrixal]

I hope you take no offense to this, but you misconstrued their function almost entirely. The point of these gravastars is that they follow the quantum model whereas your expertise lies in the regular model which predicts black holes. if the collapse of a sufficiently large star does follow the quantum model rather than the regular, it would form a gravastar as far as we understand since the quantum model does not allow for mass to be infinitely condensed, instead it forms that vacuum energy similar to how the bottom of the ocean is perfectly stable, yet unbelievably energy dense due to its compression. The shell is also not necessarily a material as you understand and is rather a boundary layer between quantum field energy and vacuum energy, not actually matter in the way you understand. Once again, this is just taking the process of a black hole formation and calculating what would happen using quantum mechanics instead. Because quantum mechanics have more complex laws, it makes a far more complex result. Anyway, as i said, i hope you don't take offense, but the reason you misunderstand is because you're applying the wrong system to the problem.

[scottkidder]

I honestly don’t buy the idea that these are any less viable than black holes. These are basically predictions that don’t involve infinities in the math which is what we get from black holes. If anything, if you see an infinity, it means you’re wrong. In fact it’s infinitely more likely that there’s a process that doesn’t include infinities, so why not this explanation? I don’t really understand it, but if it doesn’t break mathematically or break the conservation of information, it’s an improvement. The only reason we prefer black holes is because we’ve heard about them more often. But if we’re being honest, infinite density and infinite curvature makes absolutely no sense in a space we know is finite. Especially considering quantum mechanics and the standard model. Maybe I’m crazy, but it insists that there are fundamental particles and even fundamental volumes and it doesn’t describe a continuous, classical system where you can divide by infinity. So black holes break the standard model and make relativity produce nonsense answers. They also destroy information. And yet this new idea that doesn’t do any of that is somehow less likely?

I don’t know I’m very openminded on things like this just because we have no idea and pretending we do is silly. In fact if anything, we know we’re wrong. Black holes or any other explanation are about as real as string theory or the multiverse. They only make sense on paper and even then, they don’t make sense. And they don’t really have any experimental data. Black holes do, but again, it doesn’t have to be a black hole, some other explanation could account for it like a gravistar. All of the evidence we have now doesn’t put it out of the question.

[DregExheart]

Basically is like throwing a coin: one face a Blackhole, Another face is Neutron Star but ocasionally could have the chance to fell on the Rim, and that's where Gravastar are

[RoseBenson-jvxm]

So vacuum energy held in by the surface tension of a shell of unobtanium.

[nobodx]

Too be fair, in an unlimited universe, with unlimited stars, even the slightest possibility will happen unlimited times

[Hellsliver]

I understand the video as that the mass of a super nova got crushes into absolute energy fission before its mass became super condensed matter, so I speculate that the physics to achieve a gravastar is similar to a pseudo big bang that are balanced by a constant gravitational collapse. Possibly the shell could be the highest density of non moveable energy that cannot be seen as it neither emit nor reflect energy.

[supayambaek]

"a closed system where entropy is going down" not at all, the energy inside the shell is constantly trying to escape, meaning entropy is trying to go up. Also, as the shell absorb more and more energy (either from ground up matter or light) it'll expands and will take more pressure from outside until the pressure from inside can no longer keep up and burst the entire shell, releasing the energy. That's one way entropy can increase.

[Metametheus]

Black holes do expose exotic material, until we know the material at the center of a singularity that makes a singularity a singularity, we might as well just say its cheese, since a neutron star is pasta.

[ashleyxfleur]

I'd like to note a few things about the theory, or rather, lack thereof behind gravastars;
Physicists who actually believe in gravastars as an alternative explanation to black holes assume;
- The shell is a perfect fluid. Nobody knows what the fuck this is made of.
- The shell is not actually "cold". The whole atoms vibrating thing is nonsense. It seems cold due to extreme redshift from the gravity making light lose energy.
- The "compressed vaccum" is assumed to be a sort of Bose-Einstein Condensate of gravitational energy (idk how, gravity doesnt have a particle for now in the standard model)
- We can observe the difference between black holes and gravastars via their influence on null geodesics
- Gravastars are mathematically unstable if they spin. At all. Some models have suggested physical stability of the shell, but... you're working with a substance with no known properties apart from being a perfect fluid.

also, the perfect fluid sphere of death thing reminds me of yorozu from jjk :D