Is time travel possible? | Lee Cronin and Lex Fridman 

Lex' ability to ask constructive questions and push back (which proves that he actually understands what Cronin is saying) is really impressive. Me on his spot would just sit there with an open mouth wondering what is going on.

This is definitely the kind of conversation I want to listen to..... its hard for my standard brain to process but I love it!

Ive never enjoyed a conversation that I don’t understand more then this

Thank you Lex! Appreciate your consistently exceptional content

Absolutely loved this. High-level discourse, not mumbling New Agers, but intellects firmly grounded in science, taking it up to the next level. One of Lex's best!

Brilliant Lex. Absolutely brilliant. Thanks for posting

Definitely going to watch this entire interview based off this clip. Well done boys

Lex has become a master interviewer 💪🏻 what a great conversation 👍🏻

Subscribed...keep it continuous guys....

My only objection to time being fundamental, is that something that is fundamental must demonstrate a consistency in measurement. Yet time is relative to its observer. It can be warped by both mass and acceleration. I would say we need a better understanding of the nature of time before making such a bold assumption.

How is his concept of time and memory ( being fundamental) any different to the 2nd law of thermodynamics and the Universe's memory of that of order or entropy occurring in its evolution?

I can honestly say Lex has improved the way I converse with more intellectual people and all kinds really and actually improved my listening to understand and not to respond,

I enjoyed this 👍🏼

The last five seconds are the best

Lex is so flipping adorable. He seems super normal for being as brilliant as he is!

I was going back in time listening 2 this dude,wow

The 2nd law isn't fundamental to physics, it emerges from statistical physics which essentially says entropy can decrease but probability is so low due to the huge number of microstates which have higher entropy configurations

To ask what is was first the chicken or the egg is more a statement describing our condition within the present than a question about chronological causality. Our thoughts about the logical causality justifying what's actually here is always just a thought about an assumed past, while the actual observable and provable reality is that one always goes with the other within a static structure as a model of reality that hopefully grows continuously as we learn more about the actual fundamental forces at play serving us our experience.

I enjoyed this video 😊

Fascinating.

I am afraid Lee Cronin has done that thing that happens in my brain when someone comes up with an idea that shatters my previous way of looking at a problem: in this case traveling back in time.

This was captivating, thank you Lex and Lee

Time travel requires that you travel faster than c or slower than minus c. That’s why c squared is always a positive number. If it were negative we would have negative energy, which is often referred to as dark energy. There you have it, the theory of everything is c. Without c nothing exists.

When you're listening to two PhDs talk and you keep nodding your head just to stay in the discussion !

Wow, Cronin said dark energy may actually be time, even though flippantly, I say wow, because that is the same idea I have. If time slows or even appears to stop (to an external viewer/reference point) on the event horizon of a black hole, then time must be running very very fast in the middle of deep expanding space between the galaxies. If time is running fast then space must also expand if the speed of light is to remain constant for all reference points. My hypothesis also means mass does not curve space and slow time but rather it compresses space (therefore time slows so the speed of light is constant for all reference points) and in the absence of mass space expands, as we observe, and time accelerates, as we observe the expansion of space accelerating. Anyway just some thoughts I have entertained when thinking about the expanding universe. The idea dark energy is negative curvature (gravity being positive) at least in the equations was never satisfying as expanding space is not the opposite of gravity, negative curvature would imply the galaxies should be repulsing one another like they are attracted by gravity, not the space inbetween expanding.

this is what I watch myself to sleep

@6:34 i agree with Lee. People talking about if time isn't a fundamental axis but instead is possibly "emergent" don't realize it but they're mind is breaking...which isn't always necessarily a bad thing, but let's explore this one. Wow.. this is going to be a challenge for me because I suck at communication with these complex topics. Let my compartmentalized self try anyway. So...let us start with recollecting that science is foundationally about empiricism. We all begin with our own virtual sintax of birth and vaguely becoming conscious and meta-conscious. Right from the start we all are thrown into something in which consistency and patterns already exist through a common medium, and are the language that applies to everything as far as I can see. (Were doing pattern recognition and applying knowledge.)We developed math and geometry and began applying computation which is the foundation of almost all of our modern science AND theory. What I mean is...we feed info in and get output. This is the truth of physics as well. The stuff is way more moldable than people make it seem. ... See I can't stay on track. Wtf.haha. Okay, im trying alternative approach. Everything that you can possibly point to, talk about, calculate, formulate, distinguish between,sytax, logicize, model, imagine, ect...can only be because of the consistencies that we've built our formalities on _in conjunction with _ the consistencies of the natural world. We can vaguely imagine some quantum system going "back in time" but at our real end of it, we also can how aimless and incoherent that event would be to us in present. Haha the voices in my head have as many perceptives as my mind can seemingly take.

I would love to see you do these interviews with a green screen back drop with related images Would be awesome seeing the Universe , DNA , Microbes 🦠 or whatever in the background I love this podcast 👍 awesome content

Time’s is personal for earth of us, when you dies, only your time’s finished, but the moving time’s still moves, another words, the moving objects continue with time’s, and your personal time’s finish!

Assembling preassembleds is not assembling, but reassigning (whether by brute force or seeming purposeful [though of brute force afield beyond affecting the micro moments thought casually localized]).

If you were faster than the light reflected from the earth, you could look at the previous day, the previous year, or the year 50,000 BC, depending on how far you have overtaken the light. The photons from the sun to the earth take almost 9 minutes, to the edge of the solar system over an hour.

‚Life is the universe developing a memory‘

Because you can't go back to that exact visit to Houston (exact space position and time period) WITH the transportation method you have available does NOT mean that it doesn't exist anymore, and so no one can ever find that exact "moment" (space time) with a different transportation method. That space and time ( first travel to Houston) still exists. It can't simply stop existing, even if there has been assemblements out of it, it still is somewhere. Assembling states can't mean initial states cease to exist. They are mixed for some perspectives but not for others.

it takes space to look back in time

Every event in the universe is unique

Interesting!

I think time flows in many directions, not just one

I think I understand Lex's point here, though I'm not saying it's his opinion. If you say that Time is fundamental then you say its ever present, or ever existing. But what are the properties and caulities that compose Time's existence? But the guest's point is that change cannot happen without Time, and with change comes new states of existence that provide an opportunity for consciousness, movement. If time was emergent then what change could happen before it emerged? If there was no change what caused it to emerge? Interesting topic...

Finally somebody makes the argument: consciousness was not possible in the beginning of existence. The only problem is does there have to be a beginning? We predicate beginning upon our current understanding of time. What if everything is circular and multidimensional . His limited by his understanding as are we all. Doomed to question for eternity in an existence of limitless

Lex always nails it down to zero effectively, in a positive sense. About time: I rather follow Julian Barbour, noting that *expansion* is fundamental - it creates ever more possible states which are necessary for complexity to increase overall. In turn, this leads to entaxy instead of entropy as a better measure for order (or disorder). 🤓

In Buddhism, it's called dependent origination. All impermanent constructs are subject.

I may need to go and listen to this episode from the start, my brain got hot towards the end and started smoking lol

Anything is possible, if you have the time

"The future you have tomorrow won't be the same future you had yesterday." ~Rant Casey

What about reversible reactions at the quantum level ? Where is the direction of time ??

You need to have Wallace Thornhill on your show as soon as possible.

There’s so much we don’t know.

I would love to hear their perspective of the universe after a DMT break through 😱😱🤯🤯🤯🤯😂

start at 4:20 for context. i legit laughed out loud at 4:32. that's the perfect physical representation of what my brain was doing at that moment. 😂😂😂

That very last bit about what Lee said not being back in the "same place" ....he is in Austin again... but not at the "same time" and because the earth is going around the sun and the solar system orbiting around the Galactic center.... it the "same place" is the very reason my Dad and I feel like time travel into the past is not possible....the fact the Space and Time is not absolute, as held by Newtonian mechanics, but relative and we exist in a space-time continuum...further complicates the issue...imagine the energy requirements to be able to recreate a past event and have every particle of every atom of every molecule of every compound of every star of every planet of every galaxy be in the exact state/place/time for a time traveler to return back to...even if it is arbitrary and not a specific point in space-time....It would likely require more the the grand sum of the total energy in the entire Universe...so while maybe not "impossible" per se...highly highly improbable.

I wish it was

16:12 and time

Time is directly connected to gravity. Gravity directly effects heat. It's a very very difficult concept to fully describe but here it goes. Without gravity space is especially dead space. While incredibly rare, dead space exists. In a space that is at the very edge of all gravitational pull extended in every direction. As soon as you start touching gravity you start moving through time. If you were to be in gravity and then move to dead space you would slowly stop metabolism but if you were in a controlled environment like a space craft and you stopped in complete dead space, not TDS or temporary dead space witch is spots in the cosmos that dead space happens but not indefinitely. But there are other places in the cosmos that are actual Dead space and will never obtain gravity. These are the only places in the cosmos were time ceases to exist or stops. Getting there with current technology is obviously impossible. But in actual Dead space inside a space craft you would slowly recognize everything moving around you. If there long enough depending on fluctuating speed relative to the craft. Meaning the faster the craft vibrated the faster time would seem to move. If the craft were engines off and static in dead space time would seem to show down to a stop. As soon as engines go on line, time starts to show itself. Physics will find these dead spaces one day. Physics will also find space and time are not one thing but gravity, space and time are directly connected and manipulate one another completely naturally. Time is relative. Time on Earth is the same for all of us. Time on Earth is not the same as time on essentially any other planet. Although I'm sure there is another earth out there somewhere. 1 to 1 with this earth. Our time in controlled by our sun Sol, which dictates the speed of Earth. Then our planet dictates our speed. Although all of our planets have a hand in our time here in our solar system the main controlling factors for the velocity of time relative to us humans is our Sun and earth. ∆U = Q - W. F = M • A. Fa = −Fb

Lol I had this idea about the universe working itself out like an equation when I was trippin on dmt 3 months ago

Lex “pockets of complexity” Fridman

Time only exists in our heads. There is only the current.

Cronin's last point about the uniqueness of instances in space-time is dead on. Since the solar system is also moving around the galaxy, even floating seemingly still in space, you're never in the same space twice.

is time travel possible to past future i wan to do I am from india please help me out

I like Lee

My ignorance is fundamental to the lack of understanding my mind is experiencing.

Lex: In space... Lee: ... and time Me: 🤯

It's not that hard to word, Lex. Time is perceived as..... the non-spatial Continuum in which matter and energy both exist, moving with a tendency (though NOT a requirement) of "towards most entropy". or, I dunno... somethin like that

Seems like lee just wants his theory to be disproven. If they do we learn a lot, if they don’t we learn a lot. Win win scenario and what a bold idea ! Love it, very profound implications

Time is only present if there is mass. So if the universe was at one early time purely kinetic energy, time didn't exist so it must of emerged. Locally anyway.

He's saying the direction of time is fundamental. I have a theory about time. If you have ever had a long day and it just feels like the day is flying by and it has come and gone then the particle that are entangled with your own are traveling through a certain speed within space maybe a traffic jam in the universe or some kind of current which causes you to perceive that speed relative to time.

Anytime you catch yourself saying something about reality is an absolute, that's when you know you'll end up on the wrong side of history. The good news is, you'll have plenty of company.

We are the memory of the universe, manifest. An ancient complexity which once shined bright.

is time travel to past future really possible and how

Ive just watched this whole vidio without understanding one dam word! Lol

Time travels at the speed of light.

never heard a phsyicist say you can go back it time? only forward

What if are we're all part of universe's consciousness

Time is what we messure between events. So it's the messurement of a distance, just not in a geometrical way. Saying "time is fundamental" is like saying "geometrical distances are fundamental". As soon as there is at least one (spatial) dimension there's the possibility to messure the (temporal) distance between the events that occure in it. Of course you need to define the time, so everything you messure is always relative to another event, for example the transition of atoms between two different energy states. I don't see any reason to suppose that time is fundamental in a sense that there would be time but nothing to messure, meaning no events with time intervals . That would be like saying there is distance between _nothing_ without the need to define it. This wouldn't make any sense (to me). Thanks for your time 😉

something or someone designed and created that water bottle

i just entered the 4th dimension

Time is hard to put your finger on.. Two hands is much easier..

The universe exploded and we are in the fizzle, If you were 10x the size of the visible universe you’d see the firecracker pop and done, but since you are more than microscopic, you ride the spark. You can never un-explode the bomb.

Bam! God’s is always hanging in the unexplainable background. Love the way your mind works Lex.

Imagining counting one Mississippi etc. And a defined set of perceived chronological reactions aren't the same kind of time, the first is just repeatable imagination. It seems more like a lack of understanding than an actual alternating dimension

Wow, this guy might be right. What does it mean, when Time is fundamental? Why physics don't want to have Time fundamental? 🚀

Get back to me when we actually start really going back and forth to the moon, somehow this happened in 69 with a perfect phone call to Nixon, but we can't seem to do it today - well because of the radiation problem that did not seem to be an issue in 69, and when the astronauts were asked by reporters in 69 they seemed to be oblivious to it. Seems like it would make more sense to set up launching pads on the Moon to go to Mars if there is 1/6 the gravity

What if we experience the past, present and future simultaneously but we are only able to perceive the present? We don’t have eyes on the back of our heads. We have limits to our view of the Universe.

I’m still confused, but at a much higher level. 🤔

Conciousness gave rise to the water bottle. I struggle with the causality of the watter bottle. You can trace it back to the start of the universe but get nowhere. These complex ideas and discussions inevitably break down and become philosophy. ...for me anyway., maybe i just dont understand the science

Time travel is already possible through time dilation but ok whatever I guess I’ll listen to this.

Time’s is stable and moved forward, as universes move forward , and the lights does exists, We’re the ones who must fixing ourselves with the time’s, another words, time’s go forward until the end of world 🌍 when the last star ⭐️ builds up it’s black holes 🕳 and we can not be a witness by the time’s that happens!!!!!!

Is time travel possible? Maybe, but we don't even know what time is yet.

See: John Titor

Time is an aspect of electromagnetic propagation it moves and expands as a fractal of state time can not be reversed it grows and moves with the path of electricmagnetic flux lines so if you were traveling within the flux lines then you would travel within time that it takes the electricmagnetic flux line to produce the fractal geometry of Crowther. Therefore you would be considered to have time travel. Time can not be thought of as something separate from the electricmagnetic spectrum it is the result of the dielectric that causes the electricmagnetic moment which causes the geometry of mass fractally thus gravity is the result. I would really like to eliminate the word gravity because it is rather confusing word to most people because it does not discribe really what is going on. There you go.

WELL, THE PRODUCER OF THE SIMPSONS CARTOON, CERTAINLY DID KNEW A THING OR TWO ABOUT TIME TRAVEL!!!🤷‍♂️

Think of Time as a fundamental force, not a dimension. Einstein’s mistake was to conflate Space and Time. Wouldn’t it make more sense to conflate Time and Gravity. Or Time and Light. My layman’s theory is that Time and Light are equal and opposites, yin and yang. Regardless of my theory, if you consider time as a force rather than a dimension, then the “arrow” of time is conserved. Einstein’s block universe doesn’t exist.

but if Einstein was correct, then time is more of an artifact than a fundamental aspect of the universe. It emerges from gravity and the curvature of space. How does Cronin explain the notion that time slows near super massive structures like neutron stars and indeed does not seem to be able to exist within black holes?

..rather than asking is time fundamental ask is motion fundamental, because there is no time without motion...everything in the UNIVERSE is moving and absolute stillness is incomprehensible, at least for us, hahaha, the problems we have in time is when we have problems with motion, for instance, entanglement, initiation on a contemplated action...best clocks have to do with frequencies of cesium atoms, frequencies of waves that PASS (motion) through a fixed point with no significant variation say in 60 million years...was there motion in the singularity? I say more than likely and if so then there was time...

so is time travel possible according to this man :D :D :D :D

The question is, do we need time to exist????

He's a chemist, not a physicist. And it shows.

I’m with him. I think it’s possible to accelerate or decelerate the passage of time, but never reverse it.

Cronin just doesn't seem to like physicists. What I got from this discussion was that Cronin is irritated by physicists and he REALLY wants to describe everything using his assembly theory. The funny thing was that often in this conversation he just said that he didn't like the idea that time was emergent. It seemed to make him uncomfortable. And his explanations for why he believes time is fundamental were fairly weak. It seemed to just boil down to him saying "how could time go backwards? That makes no sense"

You can’t shoot fireballs like ryu but you can maybe meet yourself in the past . Yeah both sound ridiculous

Sometimes the like button is just not enough.