A question on black holes

[atrasicarius]

So, imagine that an extremely dense object, such as a neutron star, is accelerated to close to the speed of light. Its mass increases until it falls inside its Schwarzschild radius and becomes a black hole. However, to an observer flying at the same speed, the object is not a black hole. Say the observer fires some type of absurdly powerful bomb into the object which blows it apart. From a stationary perspective, the explosion would appear from inside the event horizon. Doesn't that kind of go against the whole point of an event horizon? Also, is the object a singularity or not?

[csmyth3025]

So, imagine that an extremely dense object, such as a neutron star, is accelerated to close to the speed of light. Its mass increases until it falls inside its Schwarzschild radius and becomes a black hole. However, to an observer flying at the same speed, the object is not a black hole. Say the observer fires some type of absurdly powerful bomb into the object which blows it apart. From a stationary perspective, the explosion would appear from inside the event horizon. Doesn't that kind of go against the whole point of an event horizon? Also, is the object a singularity or not?

The invariant mass of the neutron star stays the same no matter how fast it's going relative to an observer. The relativistic mass that you observe doesn't turn it into a black hole. See http://en.wikipedia..../Invariant_mass

and...

http://en.wikipedia....rgy_equivalence

 

Chris

[timo]

From a more basic perspective: the Schwarzschild solution, including the Schwarzschild radius as the limit of a Black Hole, is defined for the massive object not moving and not rotating (and a few other condition that are not relevant at the moment). There is no reason to assume that your inherent assumptions about the conditions when a moving object forms a black hole are true, and the solution to your problem is "the moving object doesn't become a black hole".

Edited June 7, 2011 by timo