# How big a black hole could the whole universe make? Is that relevant ca. Big Bang? **URL:** \ **Category:** Factual Questions\ **Created:** [June 1, 2002, 5:40am UTC](https://boards.straightdope.com/t/how-big-a-black-hole-could-the-whole-universe-make-is-that-relevant-ca-big-bang/111861 "2002-06-01T05:40:45Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![knock\_knock](https://avatars.discourse-cdn.com/v4/letter/k/22d042/32.png) [@knock\_knock](https://boards.straightdope.com/u/knock_knock)\ **Post date:** [June 1, 2002, 5:40am UTC](https://boards.straightdope.com/t/how-big-a-black-hole-could-the-whole-universe-make-is-that-relevant-ca-big-bang/111861/1 "2002-06-01T05:40:45Z")
If all the mass in the universe were located densely enough in one area, how big a black hole would it make? Around the Big Bang, when all the mass in the universe was all close together, would it make sense to talk about it making a black hole? Or would the conditions at that time, including the extremely high energies, the expansion of space itself from a (near?) singularity, and the fact that the forces did not exist as we now know them make that not an issue? If there was a universal black hole around the time of the Big Bang, is it at all relevant to the life of the universe since then? ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [June 1, 2002, 6:26am UTC](https://boards.straightdope.com/t/how-big-a-black-hole-could-the-whole-universe-make-is-that-relevant-ca-big-bang/111861/2 "2002-06-01T06:26:53Z")
This is kind of interesting. The universe would make a black hole approximately (and i mean really approximately) the size of the current universe! Really huge black holes get away with being very low in density. So it’s conceivable that we’re inside a black hole. This is not really the same kind of black hole that a stellar collapse may result in, but it still has an escape speed greater than c.