What's time? | Lee Smolin | Theoretical Physicist

Lee Smolin - Theoretical Physicist
Born in New York City, Lee was educated at Hampshire College and Harvard University. He was formerly a professor at Yale, Syracuse and Penn State Universities and held postdoctoral positions at the Institute for Advanced Study, Princeton, the Institute for Theoretical Physics, Santa Barbara and the Enrico Fermi Institute, the University of Chicago. He has been a visiting professor at Imperial College London and has held various visiting positions at Oxford and Cambridge Universitiies and the Universities of Rome and Trento, and SISSA, in Italy. Lee Smolin is a theoretical physicist who works mainly on the problem of quantum gravity. He also has contributed to cosmology, the foundations of quantum mechanics, astrophysics, theoretical biology, philosophy of science and, recently, economics. In quantum gravity Dr. Smolin was one of the initiators of two research programs: loop quantum gravity and deformed special relativity. He has the last few years been pioneering a new direction based on the hypothesis that time is a fundamental and irreducible aspect of nature, and that the fundamental laws of nature evolve irreversibly.
November 22, 2019 at City of science and industry in Paris.

[@sylviarogier1]

I think I'm finally beginning to get the philosophical underpinnings of Lee's quest for a "reality-based" understanding of the foundations of physics.

[@Robinson8491]

I agree with him; I would just not focus on time so much but on the concept of the present. So presentism

[@MrSIZEMIK]

There was a young lady called bright, who could travel much faster than light, she set off one day in a relative way, and came back the previous night, , , Had to bookmark this LS video, just one word AWESOME !!

[@julioguardado]

Smolin is great. I'm in the school that law is fundamental. Strings (wink, wink) don't care about time. The fabric of spacetime doesn't even care about time. Time exists only because we mark it and need it to make physics work.

[@NextLevel-kv5kn]

Why do we need time to make physics work if it doesn't exist? Are there other nonexisting things that we need to make physics work?

[@julioguardado]

@NextLevel-kv5kn Some claim time started at the big bang, so time wasn't needed for physics to happen. Physicists use particles that don't exist to make the standard model work. There are probably particles that can't exist according to the standard model that do exist. Time is just a metric. There is no time force or time particle. Same for space. Or we're just a simulation.... 😁

[@NextLevel-kv5kn]

@@julioguardado So why is it 3am and why isn't it 3am anymore? Some claim whatever doesn't mean time wasn't needed for physics to happen. Physicists use particles that don't exist to make the standard model work. This is incorrect.

[@julioguardado]

@NextLevel-kv5kn That's like asking why isn't over there over here. Seriously though, no one really knows what is time. It's a topic of debate among people much smarter than KZbin posters, myself included. But I know I'm right. 😁

[@NextLevel-kv5kn]

@@julioguardado That is kinda like asking why isn't over there over here. So can we stop pretending that we understand time. When you do that you realize just how much we don't understand time. I made a video about it where I explain everything. Can you tell me what you think about it?

[@vanikaghajanyan7760]

41:20 Expansion is a special kind of motion, and it seems that the Universe is a non-inertial frame of reference that performs variably accelerated motion (according to general estimates, this acceleration is: a=πcH).* Real gravitational fields are variable in space and time, and, developing GR**, we can now talk about the fact of the possibility of generating gravitational field in a non-inertial frame of reference (|a|=g).. That is, finally achieve global (instead of local in GR) compliance with the equivalence principle. Then the energy density of the relic radiation, that is, the evolving primary gravitational-inertial field (= space-time): J= g^2/8πG ~1500 quanta /cm ^3, which is in order of magnitude consistent with the observational-measured data (about 500 quanta/cm ^3). By the way, it turns out that the universe is 1.6 trillion years old! P.S. You can also use the Unruh formula, but with the addition of the coefficient q, which determines the number of phase transitions of the evolving system: q=√n', where n'=L/8πr(pl), L=c/H. Thus, T*(relic)=[q]ħa/2πkc (= 0,4K), which is in order of magnitude consistent with the observational-measured data: T(relic)/T*(relic)= 2,7/0,4=6,7. {However, it seems that the presence of a factor 1/2π in the Unruh formula is not entirely physical.} --------------------- *) - w(relic)^2=πw(pl)H, |a|=r(pl)w(relic)^2 =g=πcH, intra-metagalactic gravitational potential: |ф0|=πGmpl/λrelic , m(pl)w(pl)=8πM(Universe)H; { w(relic)^2=πw(pl)H. **) - See "GR was QG".

[@vanikaghajanyan7760]

GR was QG: docs.google.com/document/d/1FyD9vlFkQmVuVHWXNJSuuk6T86aJqqFG/edit?usp=drivesdk&ouid=110286572639581187540&rtpof=true&sd=true

[@quantumcat7673]

Dr Smolin, I love the way you see current physics. I'm not a physicist (I'm an electrical engineer) but I always thought that Quantum Mechanics is bizarre simply because we do not (possibly cannot) have the full picture of the world we live in. Especially in the very small scale but also in the very large scale too. Although we know very little about the universe, 95% of it where we have no clue, biased humans will inevitably make conclusions about the whole. I think that time arise from the speed limit of the universe. I do not think that the future is already predetermined but is dynamically determined by interactions between particles. I'm glad you do not think, like Lenny Susskind or Brian Green, that current physics won't change much in the future just like physicist at the end of the 19 century thought we had discovered everything after Maxwell and Boltzmann work. After all, we are still very young babies in our great science adventure just a couple of century old!

[@scienceforfree0]

@Quantum Cat Thanks for your comment !

[@sunroad7228]

"In any system of energy, Control is what consumes energy the most. No system of energy can deliver sum useful energy in excess of the total energy put into constructing it. This universal truth applies to all systems. Energy, like time, flows from past to future".

[@MrSIZEMIK]

Hmmm, , ,Mick's been thinking = the present is a continuous but fleeting moment, that allows the future to flow into the past, , ,so does the past and future push and pull the present ?, , , SPOOKY !!

[@davecurry8305]

The Doppler effect of the spacetime continuum must be taken into consideration. Time must compress in inverse proportion to the expansion rate of the universe otherwise quantum gravity collapses. This results in a reverse big bang.

[@axle.student]

Old post but an interesting thought :) I am attempting to formulate in my own mind something akin to this. A more substantial relationship between time geometry and space geometry, where I may expect one being the inverse of the other is some sense.

[@punkypinko2965]

Too bad the audio is so low. I can just almost hear what he's saying.

[@American_Moon_at_Odysee_com]

I love Smolin's baby universe idea. I may be misrepresenting his exact idea, but I've generally thought and thought about it and added my own slant. Maybe a universe makes life because we rise to make more black holes. As power sources or something. Or, maybe the universe makes consciousness in life because that leads to us discovering how to engineer our own universes someday. Aside from black holes. Just, we learn to turn up the oven and make some new bubble universes. And maybe they use some of this universes materials. Or is organized in more orderly manner so in effect, makes more evolved universes out of this one.

[@bryandraughn9830]

I can't imagine any type of calculation that could ignore the uncertainty principle and locate the precise positions and velocities of any particles.

[@snarzetax]

Mathematics is a series of observations, nothing more.

[@grixlipanda287]

What happened to shut up and calculate?

[@edtim3550]

I am just going to suppose that he is so far ahead of me that ,for me, it all sounds like giberish. Am i just a monkey trying to read hamlet here ? He lost me on "i'm going to try ....."

[@michaelsmith6420]

Smolin correctly dissects the faults with current theo physics. Unfortunately, he hasn't a clue about how to right the ship. More of the same, is his suggestion. Total lack of constructive imagination.

[@NextLevel-kv5kn]

That's because it's so difficult. Time is different from anything else. It will be the last thing we understand.

[@axle.student]

​@@NextLevel-kv5kn "Time is different from anything else. It will be the last thing we understand." Unfortunately most have written time off as non existent, as something that is just a figment of human imagination. To even consider giving any agency to time is considered a form of heresy. I think this is why Lee steps around any direct statement on it.