But when was it conclusive to say yep these exist and we call them black holes and don’t need a theory anymore because they are fact? How come scientists say that a black hole will rip anything that enters apart. But what if treated like a shower drain. Match the speed at the lip of the black hole and slowly go down increasing speed when you get deeper. Like a funnel. Speaking of that what is the speed at which a black hole “disintegrates” stuff?
A black hole is a single point. The “funnel” doesn’t go “down” like a drain…it goes inward towards the center of that point from all directions at once.
That funnel idea is just a graphical representation that they use to illustrate the idea. But, in reality, it doesn’t make sense to represent it that way. The effect is similar, but you have to try and imagine it happening in all directions at the same time…like a spherical funnel…which is difficult to visualise.
Obligatory, I’m not a scientist but I took an astronomy class in college and we talked about black holes a bit: The simple answer for why a black hole will tear everything apart is because the acceleration due to gravity will destroy it
The fastest speed you can go is the speed of light in a vacuum. That’s the upper limit (at least as we currently understand physics I think). So theres a limit to how fast you can go even in space. Black holes are really big and therefore have a really strong gravitational pull. It’s so strong that if something gets close enough, eventually the gravity will be strong enough that even if you’re going the speed of light, you won’t be moving fast enough to escape it. So you wouldn’t be in the black hole yet, but you wouldn’t be able to escape its gravity anymore. That area is what’s called the event horizon. The closer you get to the black hole, the stronger the pull of gravity becomes and the faster you accelerate towards it. Eventually it gets to the point that the part of you that’s closer to the black hole is accelerating so fast that it’ll be ripped from the rest of you that’s slightly further away and therefore being pulled slightly slower
Because not even light can escape the event horizon, black holes don’t look like anything except… black holes or dark spots in space, which makes them hard to detect bc darkness isn’t uncommon in space. So we actually detect them by looking for the distortion of light that passes near the event horizon and by the bursts of gamma rays that are released when a black hole feeds on matter. But afaik black holes aren’t technically “fact” yet. They’re still theories because while we have good evidence for them existing, we haven’t confirmed it bc obviously we can’t see them and can’t visit them bc they’re really far away. They’re just a really well agreed upon theory. But I think there are some different theories of the specifics of how black holes work, since we don’t actually know a ton about them
As I said at the start, I’m not a scientist, this is just based off an astronomy class from college so I may well be wrong. If I am please please correct me
How do the gamma rays escape it?
The gamma rays come from the super heated gas near the blackhole. That gas hasn’t crossed the event horizon yet so thats why we can still see it
I’ll be honest, that’s one of the things I didn’t fully understand myself from the class. I tried to do a bit of reading to refresh my memory and I realized I was thinking of accretion disks, not gamma ray bursts. Black holes can emit gamma ray bursts apparently but I think they only emit it when they eat a star and the star explodes as it’s being pulled apart. So the burst we see is a part that’s still able to escape. I think
Accretion disks though are another way we can detect blacks holes. Because of their massive gravity, black holes draw in a lot of matter that orbits it until it eventually passes the event horizon and can no longer be detected. Before that though, all the matter, whether it be gasses or parts of stars or planets that have been torn apart, rubs together and heats up, emitting light that we can detect until it eventually is pulled past the event horizon
Like I said before, there’s still a lot we don’t know about black holes because they’re hard to find, let alone study. Honestly, the more I learned in that astronomy class, the more I realized just how much we don’t fully understand about the universe yet. We have so much left to learn and discover that it’s kind of exciting to think about what will be discovered next in our lifetime!
Depending on you define “directly observe,” but here’s a “picture” of a black hole.
DrBob@lemmy.ca 1 week ago
You misunderstand what a theory vs a fact is. If a fact is a lego brick,a theory is a what you build.
A theory collects facts and builds a cohesive narrative to explain why they are. Most importantly there will be gaps, so a theory makes predictions about facts that we don’t have yet. When a new finding fits expectations, then the theory is supported. When a new finding is unexpected or doesn’t fit, it’s time to reclaim the bricks and build a new structure.
So black holes were predicted and fit the theory very well. It increased our confidence that the theory was moving in the right direction.