Name: Distant time and the hint of a multiverse
Uploaded: 2011-05-05T02:40:00Z
Duration: 15 min 37 s
Description: Cosmologist Sean Carroll attacks -- in an entertaining and thought-provoking tour through the nature of time and the universe -- a deceptively simple question: Why does time exist at all? The potential answers point to a surprising view of the nature of the universe, and our place in it.

The Universe: Hubble Ultra Deep Field

Squelching Boltzmann Brains (And Maybe Eternal Inflation)

Cosmologist Sean Carroll attacks -- in an entertaining and thought-provoking tour through the nature of time and the universe -- a deceptively simple question: Why does time exist at all? The potential answers point to a surprising view of the nature of the universe, and our place in it.

Distant time and the hint of a multiverse

Time’s relentless forward march is rooted in a deep puzzle: the early universe was astonishingly smooth and low in entropy, a delicate starting point unlikely to arise by chance. There are roughly a hundred billion galaxies, each with a hundred billion stars, yet they were once packed into a region smaller than a grapefruit. Scientists have discovered that the universe is not only expanding but accelerating, driven by dark energy that fills even empty space. Grappling with why our universe began with such order—and whether it’s just a tiny part of a vast multiverse—forces us to rethink our place in time.