# Thread: See you on the other side...

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Originally Posted by dhjana
Maybe she meant anti-matter.

But I don't think that a black hole would devour anything slowly. If it started big enough that it wouldn't just disappear immediately, then the more it pulls in the stronger it gets and I don't know what is the proportion of mass and gravity for black holes, i still bet it would be significantly bigger then earth's in a short while. And even if it did just sink into earth and eat it slowly it would still mess up earth because the first think it eats then would be iron and, poof, there goes the magnetic field.
There's a limit to how fast black holes can devour material, which is relative to their mass. Any black hole that this Large Hadron Collider could make would be smaller than an atom, so it wouldn't be able to devour material fast at all.

Are Microscopic Black Holes Buzzing Inside the Earth? | Universe Today

From what I understand about black holes, they don't actually produce any more gravity than the mass it has consumed. The reason why a black hole is inescapable is not because the gravity is stronger, it's because its schwarzschild radius (the distance away from the centre of the mass at which the gravity becomes inescapable, or the event horizon) is larger than the radius of the object itself. For every other object in the universe the schwarzschild radius is smaller than the actual object is, so it's impossible for the object to trap anything. For instance, Earth's schwarzschild radius is less than a centimetre wide, and it's impossible to get trapped by gravity because as you get closer to the core of the Earth and its schwarzschild radius, gravity would get weaker because the matter that makes up the outer crust of the planet will start pulling you away from the core instead of towards the core. If you were to make it to the centre of the Earth, instead of being trapped there the gravity of Earth's matter would be pulling on you uniformly from all directions, canceling itself out. You would be floating in zero G.
Last edited by MadDogMike; 04-08-2008 at 05:05 PM.

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Am I the only one that wants to see a 50's B movie on this very subject?

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^ There's a novel you can read about it. It's called "Hole Man" by Larry Niven, but it's based on Mars instead of Earth.

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their going to fail, just like they did last time, and the time before.

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Originally Posted by Terasiel
Am I the only one that wants to see a 50's B movie on this very subject?
I'd point to this movie,

SCIFI.COM | Black Hole

But even by 50's B movie standards, it sucked big time. I'd rather watch a rerun of The Monolith Monsters.

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From what I understand about black holes, they don't actually produce any more gravity than the mass it has consumed. The reason why a black hole is inescapable is not because the gravity is stronger, it's because its schwarzschild radius (the distance away from the centre of the mass at which the gravity becomes inescapable, or the event horizon) is larger than the radius of the object itself. For every other object in the universe the schwarzschild radius is smaller than the actual object is, so it's impossible for the object to trap anything. For instance, Earth's schwarzschild radius is less than a centimetre wide, and it's impossible to get trapped by gravity because as you get closer to the core of the Earth and its schwarzschild radius, gravity would get weaker because the matter that makes up the outer crust of the planet will start pulling you away from the core instead of towards the core. If you were to make it to the centre of the Earth, instead of being trapped there the gravity of Earth's matter would be pulling on you uniformly from all directions, canceling itself out. You would be floating in zero G.
Not quite.

Any uniform shell exerts 0N of force on any object inside of it so it can be ignored, for any object outside of it, it can be replaced with a point mass. So for any object embedded inside of a uniform sphere, we only need to worry about the mass the object is "above".

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Anyone else remember that movie where a black hole turned out to be a grand-daddy spider from outer space?

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Not quite.

Any uniform shell exerts 0N of force on any object inside of it so it can be ignored, for any object outside of it, it can be replaced with a point mass. So for any object embedded inside of a uniform sphere, we only need to worry about the mass the object is "above".
I understand that, but I tried to put it in layman's terms for the regular forum reader.

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You want laymen? This is all I got out of that: "These objects' mass have gravitational pull on the inside, so ignore that, things touching the outside will have point mass. Nothing inside counts."

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Originally Posted by Terasiel
You want laymen? This is all I got out of that: "These objects' mass have gravitational pull on the inside, so ignore that, things touching the outside will have point mass. Nothing inside counts."
I wasn't talking about black holes really, they aren't really spheres for one thing.

And you basically switched it around, once they've been passed, the outer shell no longer matters.

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