Thread: Black holes and gravity.

I don't know all the big words or einstein's stuff so please be patient with me, my question is, why is it that gravity can escape a black hole when it too is supposed to travel at light speed, and people say nothing gets out of a black hole ??

Originally Posted by Home200

I don't know all the big words or einstein's stuff so please be patient with me, my question is, why is it that gravity can escape a black hole when it too is supposed to travel at light speed, and people say nothing gets out of a black hole ??

In the picture of Genaral Relativity, gravity causes the space fabric (if you will) to bend. It is understood as a result of the curvature of space. So there is nothing that escapes a Black Hole in order to cause a gravitational force. It is the bent shape of space itself that causes it.

It is a bit different in the quantum field picture, where particles - the gravitons - are postulated that are the carriers of the force.

I thought I made it clear I don't understand all that stuff, so why just reply with it?

Please, if you can't explain it in a way that a normal kid can understand it then don't reply, there's no need to show off.

Originally Posted by Dishmaster

Originally Posted by Home200

I don't know all the big words or einstein's stuff so please be patient with me, my question is, why is it that gravity can escape a black hole when it too is supposed to travel at light speed, and people say nothing gets out of a black hole ??

In the picture of Genaral Relativity, gravity causes the space fabric (if you will) to bend. It is understood as a result of the curvature of space. So there is nothing that escapes a Black Hole in order to cause a gravitational force. It is the bent shape of space itself that causes it.

It is a bit different in the quantum field picture, where particles - the gravitons - are postulated that are the carriers of the force.

Why is space bent?
That is just the easiest way to describe it. But the force itself is matter attempting to limit its surface area, and conserve energy. Matter is nothing but energy being transferred from galaxy to galaxy.

Isnt it quite possible that this fabric has a uniform wave, and we just happen to be on the part of that wave that is "cupped"? This forces matter together in our part of the visible universe(condensation), but in other parts (purely speculative of course) matter is turned back into energy(steam). Imagine that these lower parts are "colder" and the higher parts are "hotter", as the hot steam(matter that has been converted to energy) is pulled down by the cold trough of the wave, it is slowed down, and forms the most efficient form for heatloss, a sphere(suns, planets). If you were to cause the cooling faster, this form would be even more efficient(snowflake).

Originally Posted by Home200

I thought I made it clear I don't understand all that stuff, so why just reply with it?

Please, if you can't explain it in a way that a normal kid can understand it then don't reply, there's no need to show off.

I'm sorry?! Now, what is so difficult to understand about my reply?Maybe you should have specified a bit better your level of knowledge. Okay, let me try to break it down even a bit more.

You have to imagine space like an invisible fabric or cloth that reacts on gravity, just like a membrane of rubber reacts to something that is put on it. This produces a cavity in that membrane. This picture can be understood as an analogue to the 3D configuration of massive bodies in space.

Now, if you put something on the bent rubber membrane, it gets "attracted" by the mass in the centre of he cavity, although there is no real connection between them. So, the additional body only reacts on the curvature of the membrane caused by the central massive body.

This is exactly how you should try to imagine what is going on in space and in Black Holes. I know, it is difficult, and I doubt that anyone can really do that. But the 2D analogue helps. The mass inside the black hole bends the space fabric like a rubber membrane creating something like a funnel. The resulting curvature makes any additional body "outside" the Black Hole react on it and it falls towards it.

Hope, this was better.

Originally Posted by Home200

I don't know all the big words or einstein's stuff so please be patient with me, my question is, why is it that gravity can escape a black hole when it too is supposed to travel at light speed, and people say nothing gets out of a black hole ??

The explanation is easy. Gravity cannot stop gravity so the speed of light here is irrelevant.

As to space, it is literally nothing. It gets definition by matter, energy, gravity, etc in it. People talk of curved space due to gravity but no one talks of heat space when infra-red radiation travels through it or radio space when radio waves travel through it. Curved space is just a silly name dreamed up by people who confuse a mathematics page with the real world.

Originally Posted by Cyberia

Originally Posted by Home200

I don't know all the big words or einstein's stuff so please be patient with me, my question is, why is it that gravity can escape a black hole when it too is supposed to travel at light speed, and people say nothing gets out of a black hole ??

The explanation is easy. Gravity cannot stop gravity so the speed of light here is irrelevant.

As to space, it is literally nothing. It gets definition by matter, energy, gravity, etc in it. People talk of curved space due to gravity but no one talks of heat space when infra-red radiation travels through it or radio space when radio waves travel through it. Curved space is just a silly name dreamed up by people who confuse a mathematics page with the real world.

So, how do you explain gravitational lensing if not by space distorted by gravity? You do not seriously suggest that massless photons are actually attracted by the mass producing the gravitational force.