VLBA observations key to 'complete description' of black hole (light, telescope, mysteries)

[Brian.Pearson]

For the first time, astronomers have produced a complete description of a black hole, a concentration of mass so dense that not even light can escape its powerful gravitational pull. Their precise measurements have allowed them to reconstruct the history of the object from its birth some six million years ago.


Using several telescopes, both ground-based and in orbit, the scientists unravelled longstanding mysteries about the object called Cygnus X-1, a famous binary-star system discovered to be strongly emitting X-rays nearly a half-century ago. The system consists of a black hole and a companion star from which the black hole is drawing material. The scientists' efforts yielded the most accurate measurements ever of the black hole's mass and spin rate.

[NightBazaar]

Here's a video that was released on the same date as the Eureka Alert article. I saw this at the time, then promptly fogot where I saw it. Anyway the gist of it is that it gets down to just two numbers to describe a black hole: The mass of the black hole and it's spin.



Black Holes: Just Two Numbers Is All You Need - YouTube

[Brian.Pearson]

Oddly, I had never thought of the spin of a black hold having a limit.