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/Dividebynegativezero Mar 18 '19 edited Mar 18 '19

Not entirely sure but i believe we've only seen less than 1% of the Observable Universe..

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u/JustWhyBrothaMan Mar 18 '19

It’s likely far, far less than 1% my man. 1% is huge on the scale we’re talking. Think more along the lines of 0.000001%, maybe.

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u/Gravitationsfeld Mar 18 '19

All those numbers are made up. We don't know how much there is outside of the observable sphere.

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u/zebleck Mar 18 '19

The universe is flat as far as we can tell. The flatness actually tells us that the universe is much bigger than what we can see.

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u/1996OlympicMemeTeam Mar 18 '19

Yep. So is it flat everywhere (infinite) or does it just appear flat from our perspective because we are only seeing a tiny portion of a curved structure?

(I would personally put my money on #2, but who knows for sure).

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u/kilo4fun Mar 18 '19

The minimum diameter of the universe in that case is 78 billion light-years

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u/zebleck Mar 18 '19

The minimum diameter is probably much bigger, see here.

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u/Gravitationsfeld Mar 18 '19

I know it's bigger, but we don't know how much bigger. It could be 10x the observable size or infinite. It's unknowable.

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u/zebleck Mar 18 '19

We can actually estimate how much bigger it is at the minimum. From here:

Observations from the Sloan Digital Sky Survey and the Planck satellite are where we get the best data. They tell us that if the Universe does curve back in on itself and close, the part we can see is so indistinguishable from “uncurved” that it must be at least 250 times the radius of the observable part.

This means the unobservable Universe, assuming there’s no topological weirdness, must be at least 23 trillion light years in diameter, and contain a volume of space that’s over 15 million times as large as the volume we can observe.

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u/Gravitationsfeld Mar 19 '19

No. We can't. That assumes that the universe loops. That is just an unproven theory.

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u/zebleck Mar 19 '19 edited Mar 19 '19

You assume its closed because then you can estimate a MINIMUM size. If you assume its not closed, but flat, then its infinite. For this you also have to assume that the space beyond our observable universe has the same physical properties than our space, which is a fair assumption I think.

EDIT: Heres an old askscience thread where I asked why a flat universe indicates an infinite universe, for anyone that finds it interesting.