if there is even just one blackhole, wouldnt it just keep on consuming matter and eventually consume everything?
In: Planetary Science
A black hole will consume all matter within the range of its gravitational influence, but that’s not infinite. We’re not in the influence of, say, Alpha Centauri; if it turned into a black hole, we wouldn’t really notice as far as potentially getting sucked in is concerned.
Black holes aren’t special in terms of how their gravity pulls on things, they’re just special because they’re very dense so the force of gravity on their “surface” is extremely high.
The Earth could be a black hole if it was all compressed down to a little smaller than a centimeter across. If that happened the moon and all the satellites orbiting the Earth wouldn’t even really notice – from their orbit the gravitational pull of the Earth is the same, the only difference would be that light can’t escape from the surface of the Earth anymore.
So really the reason why black holes don’t destroy the universe is the exact same as why the Earth doesn’t destroy the universe, or the sun, or any object in space. Everything is moving around really fast, and even though they’re pulling on each other through gravity the force they’re pulling with usually just isn’t enough to really affect things that don’t happen to accidentally pass really close on their own.
Black holes simply have a point, pretty close to them, where matter can’t escape. They don’t really have a ‘pulling’ force greater than their mass would allow, dragging on everything far away. If the sun were replaced with a black hole of equal mass, the only difference for us is that it would become dark, but we’d still keep orbiting it the same way we have been.
Time is long, space is large, orbits are stable, and there are other sources of gravity on the other side of everything
For the same reason the the stars and galaxies they’re born from don’t.
Black holes don’t just arbitrarily suck everything in from any distance. They still obey normal gravity.
The only difference between black holes and other objects is size. Boack holes are incredibly compact for their mass. So when you get really close to them, things can get weird.
But further away, from the perspective of gravity, there’s no difference between a black hole or a star of the same mass.
The gravity of a black hole isn’t any different than any other celestial body. It consumes whatever falls into it, *just like the Sun does,* or any other star, or the Earth. It’s perfectly normal for matter, or whole solar systems, to be in stable orbits around a supermassive black hole for billions of years.
It’s theorized that supermassive black holes at the centers of galaxies will eventually consume their entire galaxies, in like… trillions of years, but this is purely in “theories about the end of the universe” territory, and depends on so much that we don’t know about dark energy and the expansion of space.
Think like a shop vac hose put in the middle of a shops floor covered in woodchips. Turn the vacume on and hold the hose stationary. It will consume all the dust with in a range of the nossle however its not pulling all the rooms sawdust to it self.
That edge is like the event horizon of the black hole. It can’t get at things beyond that range.
Outside of their event horizon, black holes don’t behave much differently than any other object of similar mass. If the sun somehow suddenly turned into a black hole, the planets would continue in their orbits.
No it wouldn’t for the same reason any other stellar body hasn’t. Stuff in space tends to stabilize into orbits. Some stuff will collapse in, but others will be in a stable orbit (or at least a very slowly decaying one). Stuff can orbit black holes without falling in like the earth orbits the sun without falling in. If you swapped the sun with a black hole of the same mass, none of the plants would orbit noticeably different.
Also, black holes evaporate over time due to hawking radiation. They’re not forever.
They are just objects with mass and behave like any object with mass until you get to the event horizon. They don’t have some magical pulling power.
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