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When the universe was dense, gravity dominated. As it expands, dark energy gets more and more important. From Ars Technica's article: "If dark matter gives ris
by not2b 3y ago
When the universe was dense, gravity dominated. As it expands, dark energy gets more and more important. From Ars Technica's article:
"If dark matter gives rise to the gravity that holds the universe together, then dark energy is the counter-force pushing the universe apart. Very early in the universe’s existence, dark matter dominated. Everything was closer together, so its density was higher than that of the dark energy, and its gravitational pull was stronger so the early galaxies could form. But as the universe continued to expand, the dark matter density, and hence the gravitational pull, decreased until it was less than that of the dark energy. So instead of the expected slowdown in the expansion rate, the now-dominant dark energy began pushing the universe apart at ever-faster rates."
- DrBazza 3y agoStill hoping for micro-black holes as the solution as the early universe density must have been enough for some to form. Also, where's the anti-matter gone?
- snarkconjecture 3y agoBoth of those are pressureless, so they could be dark matter but not dark energy. Except that primordial black holes are ruled out (as 100% of dark matter) by various observational bounds, and antimatter would be just as visible as normal matter and not "dark" at all.
- superjan 3y agoWell, if we suppose all the anti-matter is in those black holes, we kill two birds with one stone. It’s ridiculous, I know, but your remark made me realize that an anti-matter black hole is essentially indistinguishable from a ‘normal’ one.
- BlueTemplar 3y agoCould just be the anthropic principle at work : in a ridiculously large universe, we live in a tiny fraction of it where local fluctuations in the respective distributions of matter and antimatter have happened to favor matter. (And the observable universe is even smaller than that.)