gravitational waves limit the possible explanations for the formation of black holes outside of our galaxy tagged posts

The black hole named Cygnus X-1 formed when a large star caved in. This black hole pulls matter from the blue star beside it.
Credit: NASA/CXC/M.Weiss

Physicists have described how observations of gravitational waves limit the possible explanations for the formation of black holes outside of our galaxy; either they are spinning more slowly than black holes in our own galaxy or they spin rapidly but are ‘tumbled around’ with spins randomly oriented to their orbit. The paper, published in Nature, is based on data that came about following landmark observations of gravitational waves by the LIGO gravitational wave detector in 2015 and again in 2017.

In our own galaxy we have been able to electromagnetically observe black holes orbited by stars and map their behaviour – notably their rapid spin...