umdhep@eneevax.UUCP (Todd Aven) (08/20/85)
Here's a simple question with perhaps a not-so-simple solution: I am led to understand that time is slower as one approaches a black hole. Can a black hole collide with another black hole in a finite length of time in a) its reference frame or b) in an inertial reference frame outside the pair? I guess that the solution depends upon the convergence of an integral with respect to time, but I don't have the background to set up the integral. ============================================================ |Todd Aven MANAGER@UMDHEP.BITNET | |Softwear Sweatshop AVEN@UMCINCOM (arpanet, bitnet)| |High Energy Physics UMDHEP@ENEEVAX.UUCP | |University of Maryland | |College Park, MD 20742 (301)454-3508 | ============================================================
rimey@ucbmiro.ARPA (Ken Rimey) (08/22/85)
Todd Aven asks, >Can a black hole collide with another black hole in a finite >length of time in > a) its reference frame or > b) in an inertial reference frame outside the pair? The easy case to consider is that where one of the black holes is much smaller than the other. Then the smaller one will not perturb the larger one, and it will follow the same trajectory any small particle would follow. It will cross the Schwarzschild radius and hit the central singularity in a finite time as measured by someone riding on the particle. Of course, in speaking of a rider on the particle I am presuming that it is not a black hole. It is not clear what would be meant by the "reference frame" of a black hole. Question (b) makes sense in the general case. Everyone is taught the answer for the case of a black hole and a small test particle (which might as well be a black hole): The small particle never reaches the Schwarzschild radius. But what happens if instead of a small test particle we use a black hole comparable in size to the other black hole? I don't know. Do any of you people? Ken Rimey rimey@dali.berkeley.edu