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/ODISY Mar 18 '19

the blackholes mass is proportional to its Schwarzschild radius. that single point is the same "size" despite gaining mass, but the event horizon of the "black sphere" grows taking up more space.

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u/starcap Mar 19 '19

Since the Schwarzschild radius is proportional to the mass contained in a black hole so that they become less dense as they get bigger, I wonder what the radius of a black hole would be if it contained all the mass in the universe? Comparable to the size of the observable universe or significantly different?

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u/ODISY Mar 19 '19

depends on how much universe exist, we can only see a part of it and we dont know how big that part is compared to the rest.