Timeline for Density of infinite gas cloud
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| Apr 4, 2018 at 13:49 | comment | added | Anders Sandberg | The cosmological constant further complicates things: it allows universes with more mass that yet do not collapse. The quick answer to Ola's comment is that black holes are concentrations of mass surrounded by largely empty space while cosmological models have the same density of stuff everywhere but have some global curvature. The kinds of singularities and overall topology are different (black holes: space is $R^3$ minus a point, times a time dimension; cosmology space is $S^3$ or $R^3$ times a time dimension, with at least a past spacelike singularity as a past & maybe a future boundary). | |
| Apr 4, 2018 at 13:37 | comment | added | JEB | Well, maybe it is. If the density of the Universe is greater than the critical density (which is very close to the density described in the answer), then the Big Crunch will happen, and that means, no matter how fast we move in any direction, it is still on our future world line. Kinda sounds like life inside an event horizon. | |
| Apr 4, 2018 at 12:18 | comment | added | Ola | What prevents our universe from "being" a black hole, then? The fact that it is expanding due to dark energy? | |
| Apr 4, 2018 at 11:35 | history | answered | Anders Sandberg | CC BY-SA 3.0 |