yes. Force causes acceleration. I asked what force the being should apply to make room accelerate so that the man inside when lets go off the ball sees the ball travel to the ground (accelerate) near to speed of light? I am sure i have made things clear by this statement. Ok language barrier is there.i am very poor in language.
so black hole in this way is impossible right? Since blackhole can make ball travel at speed of light? Am i right?
Black holes don't have infinite gravitational acceleration. A black hole with the mass of the Sun would only have a gravitational acceleration equal to the Sun's (outside its event horizon). So, if the Earth was a black hole, then you'd only need to accelerate your object at 9.8 metres per second per second to create the same acceleration as the black-hole Earth's gravitational field at the distance of the Earth's current surface. No. You're wrong. See above.
That means the reason by light is not able to escape from blackhole : space is that curved that it has ripe apart. So the reason why light is not able to escape from the blackhole is independent of acceleration produced by blackhole. Am i right?
and the reason why an object turns into a blackhole is the answer that eram gave in his first post. When an object's radius become smaller than critical radius,it is able to break apart the space,turning it into blackhole..
Once you go within the Schwarzschild radius/event horizon (< R), all spacetime paths lead closer to the black hole's center. This applies to everything, including light. Basically, once you're within event horizon, you're permanently screwed Please Register or Log in to view the hidden image! Note that the Schwarzschild radius is not equivalent to the event horizon in a rotating black hole, such as a Kerr black hole.
what? Again a language barrier? C'mon,i have expressed in the way that everyone understands in this case!!
yes.then why can't light escape if earth was turned into blackhole? Inother way, if an object wants to escape from the gravitational field,object's acceleration should be greater than earth blackhole. Well,light has its velocity higher than earthblackhole's escape velocity. Then we would visibly see it. Since blackholes cannot be seen,then how does this make sense?
Because if the Earth became a black hole then it wouldn't have the same escape velocity. It would take crushing the Earth to about the size of a marble. Then it would have more density, and a smaller radius. Then the gravitational force would increase, it would then have a higher escape velocity from the surface. It would then just be much smaller and have a smaller event horizon. So then you wouldn't be able to see the little black marble that would then be Earth.
look at the comment of james r. He said acceleration due to gravity remains the same.so wouldn't escape velocity remain the same?
Yes, look at JamesR's comment, he said, at the distance of the Earth's current surface. A black hole the same mass as the earth would have an event horizon with a radius of less than 1 cm. Thats how close to the center of the BH you would have to get for the escape velocity to equal the speed of light. The acceleration due to gravity at that distance would be ~5e17 time that at the present surface of the Earth. On the other hand, a super massive black hole of 1 billion solar masses would have an event horizon twenty times the radius of the Earth's orbit around the Sun and an acceleration due to gravity of ~6069 times that of the Earth's surface at the event horizon while still having an escape velocity of c. This is because there is not a direct relationship between escape velocity and surface gravity. (We even have an example of this in our own Solar system; The surface gravity of Uranus is less than that of the Earth's, yet its escape velocity is more.)
Then why did JamesR said that ""to create a gravitational field equivalent to black hole's, an object needs to travel faster than the speed of light or it needs to travel at the speed of light."" is wrong?
