Black holes are massive enough to distort spacetime itself. Light still travels in a straight path at the speed of light, but that "straight line" is actually curved by the black hole. Once you cross beyond the Event Horizon, all spacetime paths that point out away from the black hole are curved enough that it directs itself back into the black hole. That's the reason that even if you were to build a spaceship that traveled faster than light and crossed into the Event Horizon, you'd still never be able to leave. There would be no direction that you could point that would take you away from the black hole.

It's like if you were to make a Hot Wheels race track that goes in a circle. The cares are propelled forward and only move forward, but the track itself is curved. Not the best analogy, I'll admit, but it should be at least enough to understand what's going on by a black hole.

What is space-time made out of?

Photons, derp

Made of (spatial) dimensions and time integrated in them. They're pretty abstract, but it's basically what we are in, the "ether" of our time. In mathematics we think of this as a plane where we calculate things.

I don't know if you're serious or trolling, but I sincerely hope not the latter.

This post was edited by Holod on Sep 20 2011 01:03pm

What do you mean? Space-time makes up the four dimensional reality in which we live -- three spatial dimensions, and time. You essentially just asked what is "up or down" made of.

http://en.wikipedia.org/wiki/Time : Currently, the international unit of time, the second, is defined in terms of radiation emitted by caesium atoms

herp derp derp

And the meter is defined to be 1/299792458 the distance that light can travel in one year through a vacuum. What's your point? Neither of these define what time or space are.

Ok, you wrote: '[...] light may be able to effect mass through wave transfers of energy'. This is clearly wrong.
The right formulation would be: '[...] light is able to effect mass through wave transfers of energy'. I hope this is only a linguistic error.


No, you are wrong again. You appearently have a fundamentally flawed understanding of what radiation pressure is, so I will try to clear this up for you: Heat is a thermodynamic property, and 'heat motion' is the random motion attributed to the molecules/atoms of an gas/liquid with nonzero heat Q>0. This has nothing to do with radiation pressure, which is a real transfer of momentum (in the quantum mechanical picture the photons transfer their momentum to the surface). Your misunderstanding probably arises from the http://en.wikipedia.org/wiki/Crookes%5Fradiometer (probably the experiment you are referring to is of similar nature). There, you illuminate a little fan which will then start to rotate, but not due to radiation pressure, but because some stuff on the fan will heat up, evaporate, and then heat motion will indeed move the fan.
In this case, radiation pressure is much to weak to have a measureable effect. However, radiation pressure is a totally different phenomenon than heat motion, and, I must repeat myself, is a real & measurable effect, see my first post.

Edit:
Space and time are abstract concepts to order events.

This post was edited by rolle on Sep 21 2011 03:00am

Abstract concept of locations ( space and time ) ok , but I'm talking about what it is made of.
And my 107 J/s was only for the surfaces, the +depth calc is way too hard.

''Gravity studies back up conclusions drawn from seismic data. We know that gravity values across the Yellowstone Plateau are much lower than normal, and low gravity values are associated with low rock densities. In Yellowstone the low densities imply molten, thermally expanded material. As you might expect, the lowest gravity anomalies are found in the same place where seismic velocities are slowest-under the northeast caldera rim and beyond.''

hawking radiation ....





its a fair question actually ( rather , " what is space " , is a fair question )
and the answear is , we dont really know

we can give answears that are tautologys ( space is what we live in , space is the universe we exist in , etc )
but those are not real answears