Will The Big Bang Happen ANEW (and Anew)?
Summary
PBS Space Time celebrates its 10th anniversary while exploring cyclic cosmology as an alternative to the Big Bang. The episode details how the ekpyrotic model, proposed by Paul Steinhardt and Neil Turok, uses a scalar field to create an endless cycle of expansion and contraction. This theory resolves the horizon, flatness, and monopole problems without requiring a singularity or eternal inflation. The hosts also explain the brane cosmology interpretation, where colliding branes trigger the Big Bang, and discuss future gravitational wave tests that could distinguish these models.
Topics discussed
Sponsor reads and intro
PBS Space Time 10th anniversary and merch
The appeal of cyclic universes in mythology
Big Bang problems: horizon, flatness, monopoles
Cosmic inflation as the standard solution
Inflation's downsides: multiverse and singularity
Early cyclic models and the Ekpyrotic universe
Steinhardt and Turok's scalar field proposal
Scalar fields and potential energy mechanics
The cyclic universe mechanism: contraction and bounce
How the Ekpyrotic model solves Big Bang problems
Plausibility and the Kallosh-Linde mechanism
M-theory, branes, and the bulk
Brane collisions and the origin of structure
Explaining CMB smoothness and flatness via branes
Critiques and comparison with eternal inflation
Testing the models: gravitational waves and CMB
Conclusion: infinite multiverse vs cyclic time
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