Why do people say that nothing can escape a black hole?

Question

i mean, according to howstuffworks, items being sucked in emit radiation, and can be detected, meaning that radiation has not been sucked into the black hole.

cant we make a connection between radiation and electromagnetic radiation, which in turn connects to colors, radio waves, and light?

so are there things that can escape a black hole?

http://en.wikipedia.org/wiki/Image:EM_Spectrum_Properties_edit.svg

Answer 1

A black hole has unlimited gravitational pull as its mass exceeds it's maximum volume. It's like packing a trillion marbles into a pen lid. A black hole is so dense and it's gravitational pull so huge that not even light which travels at speeds close to 10 000miles/second can escape it. That's why its called a black hole, no one can see it.

FYI, items sucked in do not emit radiation, it is the black hole itself that emits radio-active waves  

Answer 2

Important to keep in mind that "black holes" are theoretical.  They have not been proven to exist, therefore any effects / non-effects are (educated) guesswork.

Answer 3

No, the gravity is soo immense...Light can't escape, so theres no way any kinda of radiation will be visible. Lets say you walked into a black hole (if you could) with a friend sitting safely away watching, you would pass through the event horizon. And if you were to walk back out, your friend sitting safely would have aged A h**l OF A LOT since you went in, maybe 5 years. But to the person watching, you'd be stuck there for ever. The friend would not even see you going in, because there is no photons (things that carry light) to carry light back to your friend.

Answer 4

As matter falls into a black hole, it is superheated and emits x-rays.  But these x-rays are emitted before the matter crosses the event horizon (the point of no return) and are going in the opposite direction - they don't get sucked in, having no mass.  But after all the matter falls into the event horizon, we don't get any more radiation from it - nothing escapes.

Answer 5

That is true as long as it does not cross the event horizon. Once inside it however, nothing can escape because the escape velocity exceeds that of light, and nothing can move faster than light.

Answer 6

the last things that are seen are at the rim of the event hoizon, after that nothing escapes

Answer 7

As has been mentioned, once something falls into (past the event horizon) of a black hole, it cannot escape.

A black hole can emit radiation with nothing around it due to Hawking Radiation.  This is due to the tremendous curvature of space near the black hole (most especially, *small* black holes).  Virtual particles are created constantly in empty space and then recombine.  However, near a black hole, it is possible for one of them to escape whilst the other gets sucked into the black hole.  These escaping particles form "Hawking radiation" and cause the black hole to actually shrink in both size and mass (although very slowly, except in the case of very small black holes).

So, while nothing directly escapes a black hole, it is possible for a black hole to "radiate" .... and eventually evaporate!  However, this radiation is not the original infalling matter or energy that made up the mass of the black hole.

I've included some links for you to peruse.

Best regards,

Jim

Answer 8

From current understanding, there are only two things that can escape from within the event horizon of a black hole - Hawking radiation and gravity.  Personally, I'm not so sure about the gravity part.  

Answer 9

Because it really can't!

Answer 10

Black holes in the Universe are  binding forces to creat new solar system, any particle that is related to solar system will not escape.

Answer 11

It depends on how close something is to the Black Hole.  The radiation is emited before it crosses the Black Hole's event horizion - which is the furthest distance from the surface of the Black Hole where nothingcan escape.  Once matter or energy cross the event horizon, they do not get out, again.

.

Answer 12

Once matter passes through the event horizon of a black hole nothing can return.  The event horizon is simply the point around a black hole in which not even radiation or light can escape.  But there is matter circulation around black holes outside of the event horizon.  This matter is heated to billions of degrees by the gravitational force of the black hole and emits massive amounts of x-rays, but no visiblel light.  Strange huh?  No visible light, but high energy x-rays so we know there is no nuclear fusion going on.  X-rays are created at the core of stars as a direct result of nuclear fusion, and these rays take hundreds of thousands of years to reach the photosphere of a star, but by then they have lost most of their energy and are now in the form of mostly visible light and ultraviolet radiation.  But with the matter around a black hole being superheated there is not much for the x-rays to be filtered out by so they travel through empty space while still maintaining their high energy x-ray form.  I hope this helps explain this better for you.  

Another thing I forgot to mention.  When a massive star dies, sheds its outer layers and it's core collapses to become a black hole, it's gravity does not increase.  The black hole's gravity is still the same as the core of the star before it collapsed.

Answer 13

No.

Answer 14

There are very few 0%s or 100%s in nature (there is always an exception).

In this case it is not so much 'nothing can escape', but more that it is so incedible that something (an actual object) could escape.

As for things like light and other EM waves, even being so fast and having very little actual particles, they can be affected by black holes (light bends when nearby, and gets sucked in at the hole itself).

As for an object, it would be very unlikely for it to have a large enough gravitation to avoid it, as a black hole is extremely dense compressed matter from an old star, giving it a very very strong gravitiational pull.

Answer 15

stuff that get sucked in doesnt emit light. its the stuff swirling around it that hasnt yet been sucked in. it gets heated up to massive temperatures if it is right outside the event horizon (boundary) of a black hole.

there are things that do come out of a black hole though. according to stephen hawking, and all physicists will agree, it is an inherent property of space time that particles can be created out of nothing. but when this happens it is a particle-antiparticle pair, so they annihilate eachother right away. but if a particle pair were created on the event horizon of the black hole one may fall in, and the other could fall out. to satisfy conservation of energy, this would appear as if the black hole emitted a particle to an outside observer.