LIGO announces another detection GW170104

There is much discussion about the spins of the holes. This has a significant effect on the 'death spiral' which is either quicker or slower depending upon the mutual spin orientations ie. one can constrain those according to the timing of the final orbits. Interestingly the combined hole has a spin parameter of 0.64, this being a dimensionless number that compares to the maximal ( which would be 1.0 ). In effect this means that points on the event horizon are scooting around at approximately two thirds of the speed of light. What a vortex around the plug hole this is ! Given that the hole's surface is barely a thousand kilometers around* then anything in-falling would be a mere instantaneous smear before being gone forever. Wow. That's what I call a Black Hole Blender or the Ultimate Angle Grinder. :-))

Cheers, Mike.

* Black hole 'radius' goes like 3km per solar mass, so diameter 6km per solar mass, 60 solar masses is thus 6 x 60 = 360 km, for ( apparent ) circumference multiply by PI => ~ 1100 km. Time = distance/velocity = 1100/[0.64 x 300000] ~ 6 milliseconds to go around the circumference once ( as viewed from a distance ). I'm ignoring that such a fast hole would be an oblate spheroid, fatter at it's equator c/w pole to pole .....

( edit ) FWIW : there is an eerie analogy b/w black hole spins and magnetic particles, when seen in pairs. The system energy in both cases is lower when the spins are aligned anti-parallel and higher when parallel. There are other correspondences too, which has prompted some to say that subatomic particles are tiny black holes ..... but in detail no one has made the theory work yet.