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Aug 23, 2023

Before the Big Bang 11: Did the Universe Create itself? The PTC model

Posted by in categories: cosmology, evolution, quantum physics, time travel

What happened before the Big Bang? In two of our previous films we examined cyclic cosmologies and time travel universe models. Specially, the Gott and Li Model https://www.youtube.com/watch?v=79LciHWV4Qs) and Penrose’s Conformal Cyclic Cosmology https://www.youtube.com/watch?v=FVDJJVoTx7s). Recently Beth Gould and Niayesh Afshordi of the Perimeter Institute for Theoretical Physics have fused these two models together to create a startling new vision of the universe. In this film they explain their new proposal, known as Periodic Time Cosmology.

0:00 Introduction.
0:45 NIayesh’s story.
1:15 Beth’s story.
2:25 relativity.
3:26 Gott & Li model.
6:23 origins of the PTC model.
8:17 PTC periodic time cosmology.
10:55 Penrose cyclic model.
13:01 Sir Roger Penrose.
14:19 CCC and PTC
15:45 conformal rescaling and the CMB
17:28 assumptions.
18:41 why a time loop?
20:11 empirical test.
23:96 predcitions.
26:19 inflation vs PTC
30:22 gravitational waves.
31:40 cycles and the 2nd law.
32:54 paradoxes.
34:08 causality.
35:17 immortality in a cyclic universe.
38:02 eternal return.
39:21 quantum gravity.
39:57 conclusion.

Elizabeth Gould has asked to make this clarification in the written text ” “Despite the availability of infinite time in the periodic time model, this doesn’t lead to thermalization in a typical time-evolution scenario, and therefore doesn’t, strictly speaking, solve the problem related to thermalization in the power spectrum. The reason for this is that, unlike bounce models with a net expansion each cycle, our model has an effective contraction during the conformal phases. Periodic time, therefore, has a unique character in which it reuses the power spectrum from the previous cycles, which is confined to a given form due to the constraints of the system, rather than removing the old power spectrum and needing to produce a new one.”

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