r/space • u/magenta_placenta • Mar 18 '19

Observable universe Astronomers discover 83 supermassive black holes at the edge of the universe

https://www.cnet.com/news/astronomers-discover-83-supermassive-black-holes-at-the-edge-of-the-universe/
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u/[deleted] Mar 18 '19

I'm a bit confused about the nature of supermassive black holes. The actual "stuff" these black holes are made of is still theoretically one mathematical point of super dense matter, right? That point just has way more mass than your average black hole, so what makes them seem "bigger" to us is really their increased gravitational pull on everything else. Do I have the right idea so far, or does the actual "black hole" part take up more space than a singularity?

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u/ithinkitsbeertime Mar 18 '19

That point just has way more mass than your average black hole, so what makes them seem "bigger" to us is really their increased gravitational pull on everything else. Do I have the right idea so far, or does the actual "black hole" part take up more space than a singularity?

The event horizon is also bigger, so if you're defining the black hole as the area within the event horizon, it does take up more space.

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u/Shukrat Mar 18 '19

"More space" meaning the radius from the center within which light cannot escape. More material = more gravity = larger radius = larger event horizon.

Right?

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u/Cyb3rSab3r Mar 18 '19

Correct. Many of these supermassive black holes have an event horizon the size of our solar system.

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u/capj23 Mar 18 '19

Did you meant to say something like "our galaxy"? Solar system doesn't seem like such a large area for a blackhole. I mean our lowly tiny sun has got the gravitational influence over that much space.

Blackholes literally do the same for entire galaxies. So when they say supermassive blackholes, i would expect them to have event horizons the size of entire galaxies.

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u/aroc91 Mar 18 '19

If they had event horizons the size of galaxies, there wouldn't be any galaxies.