dimanche 12 novembre 2017

Big Bang, act 2

So it just dawned upon me that there's a question I should have asked the last time: so... err... why didn't it turn into a black hole anyway?

I'll take the roundabout way here because I'm lazy. Last I heard the mass of the visible universe is somewhere around 6x1052. Or thereabouts. Plus/minus one order of magnitude. The mass of the sun is around 2x1030, so that would be about 3x1022 solar masses. A 1 solar mass black hole would have a Schwarzschild radius of about 3km, so that brings us to approximately 10[sup]23[/km] or about 1010 light years for the Schwarzschild radius of the visible universe. That's about 10 billion light years radius, unless I messed up the mental maths something fierce. (Which wouldn't surprise me.)

We're not even talking about immediately after it blew up. We only need to go back a couple billion years to go back to where it should have been a black hole. Or if that plus/minus goes about 50% on the plus side, it would STILL be a black hole, and we're inside one.

So, what am i missing? If the argument against an explosion in flat space is that it would become a black hole before it can explode, how didn't it turn into a black hole anyway?

via International Skeptics Forum http://ift.tt/2hoD3pu

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