Skip to main content
Astronomy

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

8
  • 1
    $\begingroup$ FWIW, If they were heading exactly towards each other, their relative speed would be 180c/181, about .9945c. According to vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator their EH radius is about 9853 light-seconds. And don't forget they have a huge relative angular momentum too. $\endgroup$
    – PM 2Ring
    Commented Jun 24, 2019 at 21:57
  • 5
    $\begingroup$ To also spice things up further lets say they are already rotating at the Kerr's limit in opposite directions to each other so when they touch its very messy from an angular momentum conservation point of view. $\endgroup$
    – Loadwick
    Commented Jun 24, 2019 at 22:37
  • 1
    $\begingroup$ Well, SMBHs do tend to be rotating fairly close to the limit anyway, so that's not unrealistic, unlike the relative speed you've given them. ;) But it's going to make an already difficult calculation even harder. There's no analytical solution to the general 2 body problem in GR, so you have to resort to numerical methods, and trying to handle a pair of SMBHs at relativistic speed will require some very heavy number crunching just to get an estimate that's vaguely trustworthy. $\endgroup$
    – PM 2Ring
    Commented Jun 24, 2019 at 22:51
  • 5
    $\begingroup$ Possible duplicate of highspeed black holes or neutron stars on (almost) head-on collision course and kinetic energy $\endgroup$
    – eirikdaude
    Commented Jun 25, 2019 at 7:14
  • 2
    $\begingroup$ FWIW, there was a thread on xkcd a month or two ago related to this topic: Is it possible to escape from a black hole using another black hole? $\endgroup$
    – PM 2Ring
    Commented Jun 25, 2019 at 16:12