The Schwarzschild equation for a black hole's event horizon is rsh = 2GM/c2 or (1.48 x 10-27 m/kg) x M. Thus, the ratio of mass to radius is 6.7 x 1026 kg/m for all black holes.(adsbygoogle = window.adsbygoogle || []).push({});

If the mass and radius of the universe are calculated as follows,

Mass of the gravitationally connected universe, MU = c3/2GH = 9.25 x 1052 kg

Hubble distance (radius of universe), RU = c/H = 1.38 x 1026 m

where H = 2.18 x 10-18 /sec (67.15 km/sec/Mpc)

Then the ratio holds true. Two questions. One, assuming a finite universe, do we live in a black hole? Two, when the universe was much smaller (say 12 billion years ago after atoms formed), the mass to radius ratio had to be much larger, how is this interpreted?

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# Black hole radius and universe

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