Toggle light / dark theme

Theoretical physicists have a lot in common with lawyers. Both spend a lot of time looking for loopholes and inconsistencies in the rules that might be exploited somehow.

Valeri P. Frolov and Andrei Zelnikov from the University of Alberta in Canada and Pavel Krtouš from Charles University in Prague probably couldn’t get you out of a traffic fine, but they may have uncovered enough wiggle room in the laws of physics to send you back in time to make sure you didn’t speed through that school zone in the first place.

Shortcuts through spacetime known as wormholes aren’t recognized features of the cosmos. But for the better part of a century, scientists have wondered if the weft and warp instructed by relativity prescribe ways for quantum ripples – or even entire particles – to break free of their locality.

Astrophysicist Geraint Lewis of the University of Sydney in Australia recently authored a study about time dilation and said that Doctor Who’s description of time travel is accurate, as we truly don’t yet understand the limitations of time (via Reuters).

Sci-fi shows like Doctor Who can usually rely on the audience’s suspension of disbelief when diving into heady concepts, and the science doesn’t always have to be accurate — though it is much cooler when a show gets the science right. Apparently, the long-running BBC series can take pride in the fact that the Doctor’s description of time as ‘wibbly-wobbly, timey-wimey stuff, is co-opted by real-life astrophysicists.

In other words, theoretical concepts like time travel and warp drives could be possible, or they may not be. Maybe a Time Lord out there uses a British police box to travel through time. Okay, so Doctor Who probably isn’t right about that part, but there technically is still a chance that it is!

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.”

The research uses the genomes of 241 species.

A species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.

Created using Paragraph ai.

Time travel has long been a popular theme in movies, but scientists believe that the concept of time teleportation is unlikely in reality. However, they do not dismiss the possibility of time travel altogether. The laws of physics suggest that time travel may be possible, but the details are complex.

Physicists explain that traveling to the near future is relatively simple, as we are all doing it right now at a rate of one second per second. Additionally, Einstein’s special theory of relativity states that the speed at which we move affects the flow of time. In other words, the faster we travel, the slower time passes. Furthermore, Einstein’s general theory of relativity suggests that gravity also impacts the flow of time. The stronger the nearby gravity, the slower time goes.

In this episode, I discuss how our brain and body track time and the role that neurochemicals, in particular dopamine and serotonin, but also hormones such as melatonin, allow us to orient ourselves in time. I review the three types of time perception: of the past, of the present, and the future, and how dopamine and serotonin adjust both our perception of the speed of the passage of time and our memory of how long previous experiences lasted. I also discuss circannual entrainment, which is the process by which our brain and body are matched to the seasons, and circadian (24 hours) entrainment, both of which subconsciously adjust our perceived measurement of time. I explain the mechanisms of that subconscious control. And I cover the ultradian (90 minutes) rhythms that govern our ability to focus, including how to track when these 90-minute rhythms begin and end for the sake of work and productivity. I include ten tools based on the science of time perception that you can apply to enhance productivity, creativity, and relationships in various contexts.

Thank you to our sponsors:
ROKA — https://www.roka.com — code “huberman“
Athletic Greens — https://www.athleticgreens.com/huberman.
InsideTracker — https://www.insidetracker.com/huberman.

Our Patreon page:
https://www.patreon.com/andrewhuberman.

Supplements from Thorne:

Story of the distant Future.


“Able to journey “out of the body” the time traveller whirls through space and time seeking the Starmaker of the cosmos. He visits many worlds, often during periods of social and political crisis, and finally joins others travellers in developing an unusual mental community.“
Chapter list:
00:00:00 — (i) Book info.
00:04:00 — (00) Preface.
00:10:39 — (01) The Earth.
00:30:35 — (02) Interstellar Travel.
00:55:20 — (03) The Other Earth.
02:05:33 — (04) I Travel Again.
02:26:05 — (05) Worlds Innumerable.
03:18:04 — (06) Intimations of the Star Maker.
03:31:22 — (07) More Worlds.
04:38:07 — (08) Concerning the Explorers.
04:48:59 — (09) The Community of Worlds.
06:14:26 — (10) A Vision of the Galaxy.
06:35:13 — (11) Stars and Vermin.
07:21:35 — (12) A Stunted Cosmical Spirit.
07:27:46 — (13) The Beginning and the End.
08:07:41 — (14) The Myth of Creation.
08:15:30 — (15) The Maker and His Works.
09:01:25 — (16) Epilogue: Back.

Like these books? Want to help?