Supermassive black holes are outgrowing their galaxies

The growth of the biggest black holes in the Universe is outrunning the rate of formation of stars in the galaxies they inhabit, according to two new studies using data from NASA’s Chandra X-ray Observatory and other telescopes and described in our latest press release.

Read more at: https://phys.org/news/2018-02-supermassive-black-holes-outgrowing-galaxies.html#jCp

Can a very large black hole be as large as a galaxy?

Tau.Neutrino said:

Can a very large black hole be as large as a galaxy?

Sure.

https://en.wikipedia.org/wiki/Schwarzschild_radius

Michael V said:

Tau.Neutrino said:

Can a very large black hole be as large as a galaxy?

Sure.

https://en.wikipedia.org/wiki/Schwarzschild_radius

In other words, no.

In order for the Schwarzschild radius to be as large as the radius of a galaxy, it would have to contain more mass than in the visible universe. This is really a guess on my part. I’d better calculate that to see if it’s right.

To match the radius of the Large Magellanic Cloud (a typical small galaxy), the black hole’s mass would have to be 4.5*10^46 kg. That’s 20,000 times the mass of the Milky Way. So I’m wrong, the visible universe is much much heavier than that, about 10^53 kg.

Can supermassive black holes swallow everything in the universe eventually?

Divine Angel said:

Can supermassive black holes swallow everything in the universe eventually?

Supposedly they will be some of last objects left in the universe when all the stars have burnt out and no more can be formed

Divine Angel said:

Can supermassive black holes swallow everything in the universe eventually?

They can swallow most of it but eventually the black holes themselves are expected to dissolve.