Santa Fe Institute
2 HN recommenders · recommended in 3 months, 2014–2022
1:13:39 · 1.7M views · Jul 16, 2013
Leonard Susskind's Santa Fe Institute talk on the arrow of time: why the past differs from the future when physics equations are time-symmetric. He covers entropy, cosmology and Boltzmann brains.
HN commenters recommend it as a clear explanation of why time runs one way, from a leading physicist.
3 comments from Hacker News
Leonard Susskind talked about this idea and expanded on it in his talk 'Why is time a one way street' Highly recommend the talk. this video
One interesting question of this is if science changes once the other galaxy groups disappear. By that I mean if a human was to redo all previous experiments have we lost any data that would result in us building a different model of the universe than what we've built with the other galaxy groups present. Sure, we will have records of evidence from the past, but records of evidence from experiments that can no longer be repeated is no longer reliable data. This is ignoring the whole development of humanity and science in the intervening 150 billion years which may change what options are available to use then. I'm also not sure if this is the most up to date model of the universe. I've recently dived deep into quantum field theory and theoretical physics (well as deep as one can without understanding a field of spinors) and I've watched a number of lectures given over the last decade that include alternate takes on expansion. I could be completely misunderstanding what was being spoken about, but it appears one possible model of reality is a sort of bubble in hyperexpanding space that gives rise to a big bang event that eventually leads to the bubble becoming hyper expanding space itself that can give rise to further bubbles. Here is one talk. this video I recommend the whole thing if you aren't familiar with Boltzmann brains and boxes, but if you want to see the issue with the current model presented in this article go to 41 minute mark and to see a possible alternate model go
Here's a clip from physicist Leonard Susskind where he discusses some "psychic" experiences with a Russian colleague. He offers a pretty good mundane explanation, but it's still pretty incredible. this video