When two neutron stars slammed together far off in space, they created a powerful shaking in the universe —Einstein's theory of general relativity.

In general relativity, black holes are simple objects: infinitely compressed singularities, or points of matter, surrounded by smooth event horizons through which no light, energy or matter can escape.

I Have to mention here that I believe the above information is correct as for the records my personal starvation This is also fact sages in those days from Indians clearly  menses even before 600 B.C without any help of instruments  they calculated mathematically above to the potion of growth moon and other planets of our solar systems
sun and moon eclipse Calcutta by mathmathly my sages some Indians by birth humans power