Why is Time a One-Way Street?
1,688,654
Published 2013-07-16
June 26, 2013
Anyone can see that the past is different from the future. Anyone, that is, but theoretical physicists, whose equations do not seem to distinguish the past from the future. How, then, do physicists understand the "arrow of time" — the fact that the past and future are so different? Leonard Susskind will discuss the paradox of time's arrow and how physicists and cosmologists view it today.
All Comments (21)
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This is one of the best lecture you can watch on youtube. I've learnt alot. Thanks Lenny!
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Time-Space is aptly named, because the felt phenomenon of time, i.e., the changes, the motion and development, are spatial ones, which we feel/interpret as "Time". However, the "space" is observable; the "time" is not--PARTICULARLY as some sort of time-tunnel-environment IN WHICH "space" is moving, from past to future. Really, no such "time" exists. Space is ALWAYS "now", and the "developing" of "now" is what we interpret to ourselves as "Time". But it's all ALWAYS "here", "now".
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Found myself thinking of Jeremy England's ideas about order and entropy several times during this excellent talk.
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Awesome video ! Leonard is an amazing lecturer.
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A "conclusion" is where a man arrives when he gets sick of thinking.
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Nice complement to Sean Carroll's excellent discussion of this.
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very interesting talk. thank you for sharing
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Incredible physicist ... among all that I know, none explain matters better than Leonard !
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Lenny have over 300 lectures on Youtube. All of his lectures are clear and brevity. I have read his Ph.D thesis from Cornell.
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This lecture is legendary.
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...this man is great
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Susskind is the best lecturer. 41:00 Jacob Bekenstein, is the name Susskind cannot remember.
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Space and time are a unit. Spacetime. Space is expanding. What is time doing?
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I have watched all of his talks and his lectures and most of his papers. He have/had an influence on my ideas on theoretical physics and elementary particle physics.
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"No time dependence for the changes in the constants of nature"- most changes in the "constants" on which we compute our reality are random and stepwise in nature, and relative position in space may be more meaningful than time when considering infinitesimal small parcels of space...
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Besides being real, time can be complex. Nahin (An Imaginary Tale...) explains how the equations of motion of a man and a bus tells us if the man can catch the bus. This is done by interpreting complex components of time, that explains if the man can catch the bus or not. In doing so he explains how complex time maybe interpreted as indicating space !!!
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Check out the series "what we still don't know" They go trough from the start when there are just the elements in the big bang to how those elements created all ect. one of the best documentaries i've seen in years.
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Time passes at different rates for different observers. The universe is a vast, ancient sphere from our point of view, but it's a young pancake for a primordial photon. How long does it have to wait for one of Lenny's bubbles? Does it perceive its disk universe to be expanding? And what's the speed of time?
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It's been 5 years!
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29:22 story of my life
