Did the universe have a beginning or has it always existed? Is there just one universe or many? In this series we explore competing models for what happened at or before the big bang. In this episode we interview Alex Vilenkin who proposed the universe had a spontaneous origin from “nothing" and with no cause! He also showed how our big bang would not be alone, that there would be an infinite number of big bangs generating a multiverse. The idea of a universe from nothing has of course been discussed elsewhere. But here we clear up many misunderstandings of the concept with the scientist who invented it. In particular, the proposal that the universe came from nothing is not to be confused with the proposal that the universe originated from a vacuum fluctuation. Below is lit of topics we discuss. Please note we did not release the film until Alex Vilenkin saw a draft and approved it.
00intro and Alex Vilenkin talk about his early life.
2:28 The uncertainty principle
3:16 Tryon’s proposal
5:32 Inflation
7:00 Quantum Tunneling
8:21 Tunnelling From Nothing
12:38 Difference between Tryon’s and Vilenkin’s proposal
13:45 Semi Classical Gravity
15:04 What caused the universe
16:05 Interpretation of QM and implications for cosmology
19:00 Why don’t tigers appear in our living room if things can come from nothing?
21:07 how do we get a multiverse?
23:25 was inflation before or after the big bang?
25:12 Alan Guth’s reaction to Vielnkin’s multiverse proposal.
26:10 Experimental tests of the multiverse
28:17 Indirect test of the multiverse and fine tuning.
33:08 has a recent undermined the multiverse?
36:46 experimental probe of tunnelling form nothing
37:42 geometry of the universe and tunnelling form nothing.
38:50 are the physical laws just description or are they are more than that?
39:24 way are the laws of physics the way they are?
40:31 Boltzman Brain
42:15 The Hartle Hawking Proposal
43:21 Responding to Neil Turok and colleagues new critique
44:50 BGV theorem
47:15 low entropy
47:41 Does anyone back the one big bang one era universe?
48:13 Does infinity exist in the real world?
50:51 Where next for the proposal and early universe cosmology?
