{"id":164840,"date":"2023-05-31T09:24:10","date_gmt":"2023-05-31T14:24:10","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2023\/05\/before-the-big-bang-11-is-the-universe-a-time-machine"},"modified":"2023-05-31T09:24:10","modified_gmt":"2023-05-31T14:24:10","slug":"before-the-big-bang-11-is-the-universe-a-time-machine","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2023\/05\/before-the-big-bang-11-is-the-universe-a-time-machine","title":{"rendered":"Before the Big Bang 11: Is the Universe a Time Machine?"},"content":{"rendered":"<p><\/p>\n<p><iframe loading=\"lazy\" title=\"Before the Big Bang 11: Did the Universe Create itself ? The PTC model\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/cLSuM8rKMyk?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<p>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 <a href=\"https:\/\/www.youtube.com\/watch?v=79LciHWV4Qs\">https:\/\/www.youtube.com\/watch?v=79LciHWV4Qs<\/a>) and Penrose\u2019s Conformal Cyclic Cosmology <a href=\"https:\/\/www.youtube.com\/watch?v=FVDJJVoTx7s).\">https:\/\/www.youtube.com\/watch?v=FVDJJVoTx7s).<\/a> 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.<\/p>\n<p>0:00 Introduction.<br \/> 0:45 NIayesh\u2019s story.<br \/> 1:15 Beth\u2019s story.<br \/> 2:25 relativity.<br \/> 3:26 Gott &amp; Li model.<br \/> 6:23 origins of the PTC model.<br \/> 8:17 PTC periodic time cosmology.<br \/> 10:55 Penrose cyclic model.<br \/> 13:01 Sir Roger Penrose.<br \/> 14:19 CCC and PTC<br \/> 15:45 conformal rescaling and the CMB<br \/> 17:28 assumptions.<br \/> 18:41 why a time loop?<br \/> 20:11 empirical test.<br \/> 23:96 predcitions.<br \/> 26:19 inflation vs PTC<br \/> 30:22 gravitational waves.<br \/> 31:40 cycles and the 2nd law.<br \/> 32:54 paradoxes.<br \/> 34:08 causality.<br \/> 35:17 immortality in a cyclic universe.<br \/> 38:02 eternal return.<br \/> 39:21 quantum gravity.<br \/> 39:57 conclusion.<\/p>\n<p>Elizabeth Gould has asked to make this clarification in the written text \u201d \u201cDespite the availability of infinite time in the periodic time model, this doesn\u2019t lead to thermalization in a typical time-evolution scenario, and therefore doesn\u2019t, 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.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"<p>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\u2019s 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 [\u2026]<\/p>\n","protected":false},"author":661,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[33,385,1617,1515],"tags":[],"class_list":["post-164840","post","type-post","status-publish","format-standard","hentry","category-cosmology","category-evolution","category-quantum-physics","category-time-travel"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/164840","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/661"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=164840"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/164840\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=164840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=164840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=164840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}