The Paradoxes of Time Travel
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- Опубликовано: 26 сен 2024
- May 19, 2010, at the Linda Hall Library of Science, Engineering & Technology
Science fiction has introduced us all to the idea of traveling into the past - but is it really possible?
Sean Carroll, Research Professor Physics at Caltech, explores how time travel would possibly work in the context of Einstein's theory of general relativity, including the hypothetical idea of wormholes connecting distant regions of space. Dr. Carroll also discusses the logical structure of time travel, and what it implies about predestination and free will. In the end, time travel is probably not possible, but by taking the idea seriously we help understand how the universe works.
Ah way back when Sean was still in the 4:3 timeline.
And somehow it seems right.
That's actually a 4:3 ratio
@@JWStreeterright. That's what he said?
@@SuperUAP I was trying to start a youtube argument
😊
i think it’s great we still have videos like this around from before we could time travel
Right? And floating skateboards.
😆
To quote Douglas Adams, time travel was discovered simultaneously at every point in the time continuum.
I love how his words are mainly used to justify more words and some more words . It’s kind of like he is just stood there chatting sh*t.
@@transatlanticsilkcottonfabrics the results of time travel are all decided by what type of imaginary time travel people are dreaming about!
I watched this at 2am while drunk hoping it would lull me into sleep but it was so interesting I stayed awake for the entire lecture. There's something about the way Sean Carroll talks that really resonates with me.
Did ya ever think to listen sober?
@@lynnfisher3037 Yes, I tend to relisten to stuff like this multiple times. I don't normally even drink.
i wish i could go back in time and give this man a glass of water
It's on the podium with him already lol
@@ender554-b8e Wasn't there for a couple of months
@@olommentesor, was it?
Work: “can you be here in 20 min?”
Me: “That’s outside my light cone”
technically you cannot here the voice of somebody outside your light cone, nor you have any information about them or their reality
@@Staarkalinou good one.
Dude…your light cone is showing..
rkalinou 😢H09=❤
You're fired
When first started watching this, I was tempted to stop because I felt it was going to be above my head. Ironically, this man took a magnificent approach of explaining these laws of physics, in a way that I actually understand everything.
What are the laws of physics, exactly? Who wrote these so-called "laws?" Evolutionist athiests "believe" in this and often rely on the "Laws of Nature." But if you ask them, "What is "Nature?" they give the dumb buck look. It's a magical wall they cannot penetrate. Science is a circular reasoning mental exercise of futility designed to break your mind.
I wish RUclips would remember the timestamp that i fell asleep at so i can finish the lecture 😭😂
I'm the same with audio books
Audio books Co.e with timers and u can save YT vids
Set a timer on your phone where the ‘When Timer Ends’ setting is “Stop Playing”. Then you always know it’s within 30 minutes or whatever your timer is.
You can probably do this with a device that can tell when you fall asleep. Doesn't apple watch do that?
I usually try to screenshot when i feel the sleepy coming. 😂
I think Sean is keeping something back. He has obviously travelled through time. Here in 2023 he looks at least 10 years younger than he did last week.
About 13 years younger to be exact…
😂
When you read this I'm in the past you are in the future .
@@bltn7469 🤣
Hes experienced great trama from many time traveling sessions and made many mistakes all the way. Now hes here to persuade all from ever inventing travel travel through deception.
There is no time travel otherwise time traveller's would have explained it to us by now.
You would think. One option is time police. Another is MVT. And it could be traveling back in time is either physically impossible, or we don't survive as a species long enough to figure out how. In the meantime, it gives theoretical physicists something to work on and the rest of us to ponder.
Right. It cannot be accomplished by man. We have never had time travelers. God can do it obviously
@angusmackaskill3035 as you wish; in the description of my channel, there is explanation of what's going on.
That is unless their truth is suppressed and they disappear. Sounds familiar doesn't it?
The cadence of nervous academics giving talks should be harnessed to power interstellar vehicles.
At the start of "Principia Mathematica" Newton says "For the purpose of this demonstration I must assume that space and time are fixed and immutable" so it must have occurred to him that they might not be.
Time travel does not cause any paradoxes even though there is only one universe. If you travel back in time to meet your grandfather, determined to change the past by shooting him. Then nothing will prevent it, and nothing will happen to you...but on returning back to your own time, no one would know who you were since you CHANGED history and werent part of the new version...
What happens in the past, stays in the past.
@@stewiesaidthat Only depending on where you are viewing it from...
@@stewiesaidthat ...or you go back and change it.
Good point...!!
Time can slow down and even stop; but it can’t go backwards. Because time is delineated by the position of all particles relative to all other particles; the particles can never be in the same positions again.
The Spielberg movie he was talking about was Interstellar. It was going to be Spielberg before Nolan took over. Very cool.
We should start up a list of things we have a name for, but which don't actually exist, you know, like psychokenesis, levitation, ghosts, time travel, big foot, the loch ness monstucker, spider man, the list goes on.
Common sense
Spider-Man totally exists, good sir!
Why, he saved me from falling out of a window yesterday.
How dare you insinuate such a thing!
this spider verse had me wondering if there is a spider out there in the Simpsons universe that was bitten by Radioactive Man and if he teams up with spiderpig?
So refreshing to read something logical on this thread...!!
My will to survive?
Here’s one reason, in physics. one could not visit their past self:
Conservation of mass-
In physics and chemistry, the law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so the quantity can neither be added nor be removed.
law is a strong word. its more like a suggestion really
Time only flows one way, like a river. If you want the river to flow in a different direction you need to change the shape of everything surrounding the river
Ok! Let's do it!!
Liquid is quite flexible. Perhaps time is as well. There is a lot we do not know. Which is fine because it would be pretty dull with nothing left to learn.
Thanks, Michio Kaku.
Or go fast
Our preception of time flows only one way. Actual time doesn't exist
One thing I find interesting, is that if you could travel back in time and would find yourself there, what would the both of you be made of? If you could duplicate matter like that, you could basically create infinite amounts of it, which would mean that there would be a huge exploit in our universe.
Either, matter/ energy is constantly flowing through our universe and no particle is actually the same from one moment to the next, or then something would happen to either one of the versions to make it disappear, because you couldn't have the same matter in two places at once.
Also, the only way I can even begin to imagine time travel to the past is by removing oneself from the confines of whatever here is, and going outside space time, and placing themselves back into space time in a different location. Here again, you would be creating matter out of nothing, thus duplicating yourself, thus possibly creating a paradox of who is the real slim shady and actually owns the atoms one is made of.
You are never the same matter from day to day because every molecule that we're made of gets replaced from day to day.
Particle isn't at two places at once, it's either in the future or in the past.
@@AthenaStanley24 I don't think you understand what is being said here. You are made of matter, regardless of where it is now. You are not taking into consideration whether a person travels back in time for example only one second. Are the molecules the same as they were a second ago?
If so, there are now two of you made from the same molecules, and you both exist for a second, until the other you disappears. Hence, you have two sets of you, made from the exact same molecules. Heart muscles for example don't get replaced in years.
The water in your body right now might be somewhere else in a few days. Still, the water in your body has to change into water that exists in the universe. if it doesn't come from outside of the universe, it has to have existed in this universe since the beginning. It doesn't come from nowhere. Thus, if you take yourself into the past, have you brought back molecules that already exist somewhere in the past universe, or are molecules made out of particles that aren't actually the same, meaning, that is what we see actually an effect of something happening to our universe, or is everything the real concrete thing in this universe, not touched by any other effects?
My double will have to fight me for those atoms
@@Lawhnothing is being “created” in this situation. they aren’t new particles, they’re the same particles from the future. just because a particle’s future is contemporaneous with its present does not mean that it has been duplicated, or that the second particle is different, or that it’s stolen from some other universe.
if this is to make sense, you should be able to draw a world line from past to future to past again. in doing so you will see that nothing is ever duplicated, the particle’s personal history simply folds over itself.
Simply? Using this word makes me doubt your understanding of your lack of understanding, or maybe you are a genius, I can't know since I'm not one.
If I travel back in time one second, there will be two of me for one second. I would have aged one second more than otherwise. The two of me consist of what we would consider to be the same matter, separated by time and space as well. Has the matter somehow reversed it's linear directional travel through time, or has it been taken from time and space and placed back as a separate entity entirely, as you say folded. What does this reflection consist of? There is now for a moment more matter in the universe than there was before, and how will this affect the surroundings? Will there be a balance of matter outside of time, where if you take some matter from the future and put it in the past, that there is no resulting issue in that?
This doesn't make sense but it's funny enough to say out loud. If I have to pay for a car and I have half of the money and a time machine, what theory would support the idea that I would go to the car dealership, wait for my time travelling self to come back with my money, hand the cashier two half stacks of money, and then I would take the car and leave. Of course in I guess my logic there is a problem here, since I would eventually have to get the money into the time machine, so the cashier would not be able to hold on to it without destroying the universe or something.
But the point of this thought experiment is to go deeper into the balance of things. The doubling and removal of matter.
@@tonoornottono
I can't get enough of Professor Carrolls lectures. He speaks so well and is a fantastic teacher. Love his use of real world associations. Some serious & some humorous.
I love the confidence here not to admit that there may be things he doesn't know. It's like some tribal leader 5000 years ago saying we will never get to the moon because boats only move on water. 😅
I travelled 8 hours ahead in time when my alarm clock went off
RUclips: hey wanna hear a guy talk about time travel for an hour?
Me: where you been all my life?
The main issue with any kind of successful time travel is solving the precise calculation of where in SPACE you want to be when you get to that time. The earth rotates, is influenced by Jupiter and the moon, orbits the sun, travels WITH the sun around the galaxy, the galaxy moves toward the Great Attractor.. Lots of luck not winding up in empty space somewhere.. or inside the earth or some other place if you don’t get your location exactly correct for the time you are traveling to. ( and let’s not even think about being at the correct velocity relative to your location).
0:03 In Im not academy rich, we cant going back in time the best we can achieve is slow it down and that's only for the ones who are on that vessel.
And four years after this lecture, Nolan and Kip came out with Interstellar.
Interstellar is a science fiction movie.....the operative word being fiction.
Around 46:00 ... I'm guessing he's hinting to the movie Interstellar?
Yep my taughts too but he mentioned kip Thorne working with speilburg instead of Christopher Nolan
I made a travel back in time in the year 2010 and was able to see a conference of S. Carrol...
On RUclips 😂
And you weren’t able to do anything to change it 😅
@@dfv15
I just listened, had no questions..
It must have been a great trip and experience! Good for you, wish he would come to a place near me
What if you went back in recent time and killed yourself (before you lost all that crypto with FTX) and then replaced yourself and make a better financial decision?
When I traveled back in time, I made a successful campaign for exposing time travel as just pure fantasy, so nobody much believes in it any more, just a few who continue to prefer fantasy over reality.
What do you mean? Time travel is entirely possible. Many scientists concur with this.
Not with the tech we have now mind you, but that could change.
Just because you don't like it, doesn't make it fantasy.
@@mywifesboyfriend5558 yeah, scientists believe a lot of things are possible, (in theory) such as time dilation, when matter is caused to speed up to close to the speed of light. Einstein believed you could use the measurement of the speed of light multiplied times itself to calculate the amount of energy that is bound up in mass. But writing something on paper doesnt mean it's real. Time travel certainly isnt. Ghosts arent. Levitation isnt, unless you consider the short distance one magnet can repel another magnet. But maybe mind reading is real. Right now I can read your mind, and i can tell you believe ALL of those impossible phenomena.
Proof that he will present anywhere. Kudos.
Your audio engineer needs to invest in a parametric equalizer and notch out that feedback.
This is 13 years ago in a school library in Missouri…. I’m sure “parametric equalizers” weren’t top priority
@@JohnnyNiteTrain Tell the kid to use a notch filter lol.
the light cone demonstration basically destroys the entire dream of time travel. still an awesome video
The light cone is a false demonstration. The light from the light source would radiate equally in all directions, therefore it would be impossible to go outside it!
I travel back in time when I'm laying in bed trying to fall asleep.
The main problem understanding time travel is that we don't really understand what any kind of travel is, at a fundamental level. We know how to travel through space, if we want to, I can get up and walk over there, but we don't really know what that means at a fundamental level. So, the reason we don't know the answer is that we don't really understand the question sufficiently well. For instance, there are two quite different notions of "going back in time". According to one of them, I, as I am now, could somehow be transported back into the Middle Ages and find myself living in that time, complete with my memories of the future. According to the other notion, you could somehow "wind time back", so it is the Middle Ages again, but you won't be present there. You won't exist until you are born much later. The difference between these two notions corresponds to two very different ways of understanding time. One is that time is something that you travel through, albeit with no choice. The other is that somehow you are in time, but it passes. It makes all the moves, so to speak, you don't move within it.
If you go back in time, it’s completely possible to change everything about your original timeline if going back in time means going into a parallel universe that doesn’t interfere with the original
@notfiveo time travel decisions are only relative to the person traveling except in the universe’s that are affected due to unlimited possible universes…does that make sense?
@Dracarys yeah except, when you bring about the changes to the parallel universe by changing the past, the one thing that changes in the original universe that does affect others is that you are no longer present in the original universe, right?
@@Just-Browsing-123 I suppose that would be the case though it wouldn’t change the original timeline for you to be gone and would only have an effect on the future that hasn’t happened yet.
Yeah that's what the videos saying dummy
No it doesn't, get your head out of your ass, there is no time travel. @@MadBull.34
All else aside, if a particle (or person) could travel back in time to meet its past self you then have 2 particles - did you just create more mass than you started with (repeat, rinse to get many particles from your time machine)? How can the universe now have (slightly) more mass than was originally in the sum of the mass in the universe?
where you think dark matter comes from? 🤔
Your reply is interesting in that it is very book worm ish. Ask yourself this - what force or intelligence is it that tells a photon to change from a particle to a wave and back again? Of course, the answer is easy. Photons don't exist. No paradox. Just like electron probability clouds. Total nonsense. Physics is fake.
In the depths of paradox, where timelines entwine,
The mysteries of time travel, a complex design.
A journey through epochs, past and future's embrace,
Yet the paradoxes of time, we must carefully trace.
The past is a realm where we yearn to explore,
To rewrite the chapters, to even the score.
But change the past's thread, a paradox unfurls,
Affecting the future, in unpredictable whirls.
The butterfly's wing, a small act in the past,
Can lead to a tempest, a change unsurpassed.
The ripple effect, in time's endless sea,
A paradox that challenges what's meant to be.
And what of the future, that enigma so grand,
Can we alter its course, with a time traveler's hand?
A paradox arises, a loop to contend,
For how can we change what's yet to ascend?
The grandfather's paradox, a conundrum profound,
If you travel to kill, does logic astound?
If you end your own lineage, your existence denied,
A paradox that leaves the mind mystified.
The twins of relativity, time's constant refrain,
One travels through space, the other remains.
A paradox unfolds, as time slows and bends,
In the depths of the cosmos, where reality rends.
In the heart of these paradoxes, we find the key,
To the essence of time, its enigma and decree.
For as we journey through its intricate weave,
The paradoxes of time, they ask us to believe.
In the dance of past, present, and future's embrace,
The paradoxes of time travel, a celestial chase.
A reminder that time, in its essence and prime,
Is a riddle we unravel, through the corridors of time.
This is just more fantastical bs hiding behind poetry. Easy to spot. Eminem would crush you. Why are you posting about time travel on a truther site?
Time is the Movement of an object within a given Space .
Knowing what happened in the past is useful in realizing that whatever you can help prevent you from doing it again. Like pulling wings off flies. In the present you choose not to do that anymore. It won’t change the fact you did it once, but knowing you did allows you to choose not to do it again. As a kid I was stupid and did reckless things. knowing that, I matured and have no need to do them again. As an adult I now do NEW stupid things. Which hopefully I will not do again - in the future 😊
Sometimes learning the hard way is the best way... as long as no one was killed or seriously injured in the process.
Don't feel bad, no matter how stupid the things that you do now, it's not as dumb as trying to create black holes...I'm just saying.
Way I look at it, we kearn the hard way so we can teach the younger generation not to make those same mistakes, or have to learn the way we did.
That's one way to progress in this life. Just a thought.
He's wrong. It's not literally a billion web pages. It's 972,000,000.
I'm inspired by this to write a short time-travel novel. Here it is: Larry built a time machine. He got in it and went back to 1600. He walked around in "Merry Old England" for a few days, surreptitiously taking photos and audio recordings, and then he popped out of existence. Why? Because he transmitted a whole stew of infectious diseases to the Merry Old English of 1600, to which nobody in the world had the least immunity, the diseases proceeded to spread throughout the world and nearly all humanity died, including of course Larry's great-great-greats.... The End
It appears to me, that trying to travel backwards in time, is like trying to travel out of a black hole.
Would have to travel faster than speed of light which cannot be done
Two doctors stayed overnight at a farmer's house...oh wait he's talking about a completely different para docs
When I close my eyes and listen to this video, I hear Alan Alda.
Well, I guess my perception of time is just as unreliable as my ability to draw a straight line. But it's fascinating to think about how our understanding of time has evolved over the centuries, from Newton's absolute time to Einstein's theory of relativity. It really shows that even our most fundamental concepts can be challenged and refined as we learn more about the univers
Gravity as a fictitious force.
Main article: General relativity
The notion of "fictitious force" arises in Einstein's general theory of relativity. The way all masses in free fall descend at the same rate led Albert Einstein to wonder whether gravity could be modeled as a fictitious force. When F = ma, the size of the force can be measured by the size of the mass and how much the mass is being accelerated at. But all masses in free fall accelerate at the same rate of acceleration, that would mean if gravity is a force then that force changes for each object. He noted that a free falling observer along with various items in a closed box would not be able to detect any force at all, for they would all have no weight. W = mg then W zero = mg zero. In other experiments using a scale various items have various weights. Therefore now when using a scale F = ma is true, where equal acceleration truly produces different real weight forces from different masses, and F can now be measured; hence, weightless free falling reference frames are equivalent to force free inertial reference frames (the equivalence principle). Developing this insight, Einstein formulated a theory with gravity as a fictitious force, and attributed the apparent acceleration of free fall due to observers watching from a non-inertial reference frame while they are being accelerated by a force, and to the curvature of spacetime, which is a force free inertial reference frame. This idea underlies Einstein's theory of general relativity.
NIST WTC FAQ 31. How could the WTC towers collapse in speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?
NIST --> "Since the stories below the level of collapse initiation provided little resistance the building section above came down essentially in free fall."
@@davidmudry5622 Your principal premise is wrong. Mass matters. In space, two 10 gram weights will attract each other with a force 4 times as strong as two 5 gram weights, provided that all external influenceces are excluded.
@@davidhess6593 Newton said all objects in free fall have the same acceleration because a big mass might be heavier but it's also harder to push. Einstein laughed his head off, LOL, and said there is no weight in free fall, what an idiot Newton is. Any comments ?
@@davidhess6593 Q. 3 different sizes of drones are hovering inside a bus at the same distance from the back of the bus, and suddenly the bus accelerates. F = ma, what forces are on the drones during this acceleration?
@@davidmudry5622 Virtually none until the drones hit a passenger, a seat or the bus windshield.
Two pair of doxes walk into a bar. Bartender says get out.
This is a creative writing lecture by a physics professor
Yep.
Exactly, just like an episode of Star Trek.
35:58 If I understand the geometry of black holes correctly, not even faster than light travel would help you escape from beyond the event horizon. Because all possible geodesics inside the event horizon point directly to the singularity, no matter what speed youre moving, even greater than light, all motion in any direction will only bring you closer to the singularity.
Its not like a whirlpool in water, where you can imagine swimming against it to move into a direction thats not the center, and the speed of the flowing water is what determines whether you can get out or not. That analogy does actually apply but only outside the event horizon, in the ergosphere where frame-dragging exists as we know it. But instead of water flowing its spacetime itself thats flowing.
Inside the event horizon there is no light cone anymore, space and time lose meaning or they get twisted into a horrible mess. Or the light cone becomes a light beam of infinitesimal size, pointing directly into the singularity. However way you think about it
you dum
nope. think of yourself in a space ship that looks like any ship of days past with a mast and a figurehead, a sail and an anchor, as well as a deck and a crew. you're sailing on the outer boundary of the ergosphere, if you can define such a place. you have an anchor with a chain of near infinite strength, with a spot light shining directly up the chain. while that chain is in the ergosphere, you still expect the light to hit the bottom of your boat, regardless of the direction the ergosphere moves, because that chain will curve to match the movement at a certain point, the anchor and spotlight hit the event horizon and the light is no longer traveling fast enough to overcome the gravity from the singularity, just like if you were to spray a squirtgun at the moon, it's just going to fall back down. that doesn't mean the path to the moon doesn't exist, only that the propellant needed for your water is not sufficient. think about the chain, it hasn't broken, it just experiences spaghettification. a geometry that follows the chain would lead out the event horizon. the concept of the ergosphere is the embodiment of that geometry. as the black hole spins, the centrifugal force is an additional boost to the momentum of light, allowing it to break away from the singularity at a point where it would not have broken free otherwise. so while your ship may be able to pull the anchor out and see the spotlight again, the thing would have sent your ship spinning like a whip as it acted like a sail in the gravity and to pull it out, you would turn into a black hole. but a theoretical geometry does exist, it just doesn't come easy.
@@Mitchell_is_smart._You2bs_dumb I'm not reading all that shit, you dont even use physics you just use dumb analogies and there are no par breaks
There is no faster than light travel. The speed of light is the limit.
@@jhkuno88 Cherenkov radiation, tachyons
The Gita makes the case of Time travel perfectly clear, not only is it do able, it’s quite normal! What exists has never not existed. Make of that what you will!
The most significant problem is that our universe, galaxy, solar system and planet are all in constant movement. We are always traveling at very high speeds and never return to the same position. If we moved in time where would reaper. We would require a type of anchor on Earth to be our relevant location. Speed is always relative. And our location is relative. How could we build a relative location on Earth. And be careful about the location. The same location may have once be underground. While in the future your location may be in the concrete wall of a future building. Either location could be distrusting when you reappear. These problems are rarely covered in movies.
The human mind is not capable of comprehending the reality of "time". We can only try to understand it.
I thought I was an idiot, but some of these questions. Damn. Also this man is a saint. Totally patient and great at explaining things.
Very interesting. Great lecture!
Time travel is a fascinating idea that will never happen. humankind is curious and we love to imagine it.
We are traveling in time right now. Otherwise everything would happen at once.
how do you know it'll never happen? I think it will happen within 1-3 generations and will become something people with money can do as a sort of vacation with lots of rules - the time traveling companies will be watching your journey to make sure you don't violate any of the rules of time travel during your paid for vacation time traveling. That's my prediction.
Agree. Will NEVER happen. It is totally possible though. We just don’t have the means to travel that fast or hang out around a black hole.
Scientists at Cambridge University have taken advantage of the unusual properties of the quantum realm to successfully simulate a method of backward time travel that allowed them to change an event after the fact one out of four times. You may want to consider taking that experiment into account
I like to play with the idea that traveling back in time would not affect a collectively-perceived chain of events. I enjoy the idea that it instead would be more akin to a copy of you going backwards (or two copies of the same person swapping places) and taking the place of the you at that time, and in doing so the copy of you that traveled back would reverse its information to be of the exact same of the you at that point in the past. Although with this idea, the same chain of events would occur. It's a neat thought experiment.
Perhaps the current state of the environment is just the most likely outcome of every possible interaction of "time travel."
One thing that breaks my brain is that if a person travels around earth the opposite as the sun at a fast enough clip they would hypothetically be going back in time. So if a person could do a backwards rotation traveling around the earth they would be traveling through all the time zones in reverse essentially setting the calendar dates in reverse. That would be time travel. But the earth would not be traveling back in its travel of its rotation around a star. So the earth would still be traveling forward as you are traveling back through dates on the calendar. I think this might become an alternative reality not time travel
If you travel back in time you can do whatever you want because you have already done it.
I alway come away from Sean’s lectures slightly more educated and a lot more confused. My brain is just a bit like a slow clock.
Join the club. These are some mind boggling concepts. But from watching vids like this I have come to the conclusion that multiverse theory solves all paradox. I would otherwise not even know what that meant.
Multiverse theory is an explanation that makes sense. However, there are others. Personally, I think that he's succinct in his oration, but poignancy is really what he brings to the table. The explanation of light cones was fairly inaccurate, but that's understandable, as it is a two dimensional description of a four dimensional phenomenon.
@@legiongrattan7349 Which is really just the limitations of a projector screen being your means of visual aid. If he had some kind of hologram projector he could do a 3D representation, but even then to add time into it as the 4th dimension isn't really possible with visuals.
After clicking on this I wish I could go back in time
Lololol
Multiverse solves all paradox. Problem is I imagine there is no way to verify it. Unless we get some kind of quantum leap device.
Multiverse theory is a Heaven myth for atheists
I wish I could see the memories of my future self, but all I have is the infinite now
I love this man. He is so knowledgeable and speaks clearly.and honestly.
He makes physics entertaining.
Glad he doesn't mumble and lie .....
decades and centuries of knowledge in one hour for free
If time is a reference frame in space then what you would need to prove is that the past and future are a perimeter in space. Faster than light travel should be like a Pull in fabric.
I think entropy should be mapped on a hypersphere
You can't travel through time simply because time doesn't exist.
Its like saying i want to travel through red.
If time travel will ever exist it would always have existed.
If I went back in time to meet my parents I would thank them for giving berth to me and give them lots of hugs and kisses!:) same for my cousin as well! I would just give my cousin a hug!
I've been traveling in time for the last 60 years, I haven't run into those paradoxes. Or even one!
If time is what prevents everything from happening at the same "time", then it is the limit of the speed of light that gives time that property. If light had no upper speed limit, causality could not exist nor could our universe exist. So, space is required for "room" in which "things" can exist, but without time, space is essentially useless, hence we must have "spacetime" in order to have a universe in which separate events can occur.
This may appear to be obvious, but I have always somehow believed that time is the key "ingredient" which makes our universe possible.
It's really disheartening when my favorite physicists refuse to admit that we do have free will, there is enough proof just from quantum mechanics that we have free will, and just because the universe has constraints, does not mean that we don't have free will. The latter portion of that statement, is usually where all the arguments start and stop. I mean from Sean to Sam Harris to Brian Greene to a number of others. The argument is always "the universe has constraints, therefore free will is an illusion." The problem with this line of reasoning is that it's a false equivocation. Being able to do something, and being able to try and do something are NOT the same thing, and free will is entailed entirely and exclusively within the latter, not the former.
Sean here uses the example of well we think we could go back in time and kill our parents because we think we have free will. He says, "We think that if we did hope into a time machine and travel to the past, and there we were with our parents, we could then be free to make the choice to prevent them from getting together." The fact that the universe is structured in such a way, that no matter what you tried something would always upend your attempts to prevent your parents from conceiving you, is not incompatible with having free will. Because again, free will is not about choosing to do things. It's about choosing to try to do things. It's almost like saying if you choose something and you fail at it, it's proof that you don't have free will because you didn't actually have the "choice to succeed at doing it." It's a real shame that Sean and many other physicists fall into this trap.
The universe is structured in such a way that, we cannot accelerate something will mass to the speed of light. It is literally physically impossible. The fact that the universe will always keep up from reaching the speed of light is not supportive of us not having free will. In fact it has nothing to do with free will. We can however still attempt to do it, we can still try. We know it's physically impossible. Now in a completely deterministic world where free will doesn't exist and we are guided only by behavioral output influenced by stimuli input that is dictated by where particles were a second ago, which is dictated by where they were a second before that, and so on - there is no behavioral explanation as to why we would ever seek to attempt to do something we adamantly know is literally impossible. No amount of behavioral science can answer that, because there are truly no examples in the wild, humans or otherwise, of animals doing things they KNOW are impossible and thus KNOW they will fail at them.
This is of course difficult to test for because we can't know what animals "know," anymore than we can actually know what another human knows. Based on how they behave however, and what it seems they are willing to do and not willing to do, it does appear that animals will not make an attempt to do anything they know is impossible to succeed at. It seems that before an animal takes an action, chasing after a prey for example, it makes a value judgement or risk assessment about the likelihood of success at catching said prey. Now we can't know what an animal thinks, but we can infer that it won't do anything it has determined to be impossible based on the fact that it stops doing things once it's made a value judgement that continuing along the specific action is no longer viable.
After chasing it's prey for some time, if it fails to catch it, it will stop. It has made some kind of risk assessment that it's unlikely to happen and doesn't want to exert the energy necessary to continue trying, or that it's believes it's now impossible no matter how hard it tries, and this ceases any further attempts. Again we can infer it can determine something is outright impossible based on what it will and won't attempt outright. A lion, a single lion, has never been recorded attempting to single handedly take down an adult elephant. It's not that it's just determined that it's unlikely, because if that were the case, it would have at least attempted it once by now, and again, there are no records of this. Humans on the other hand, can attempt things they either know or believe are impossible, whereby discovering some things they thought were impossible were not, like humans flying. The fact that we are not bound to the conclusion of our risk assessments or value judgements, and other animal species are, reasonably indicates we quite possibly have free will.
Like maybe time travel is impossible. Maybe the universe is constructed in such a way to not allow us to go back in time. Just because that is a fundamental property of the universe, doesn't mean we don't have the free will to try it anyways.
'What do we want?'
'TIME TRAVEL!'
'When do we want it?'
'YESTERDAY!'
Time is the result of "information cannot be destroyed", which is one of 2 universal laws
Okay, I’m only ten min in and already fascinated by this lecture, so maybe he gets to the later, but how would we ever really know if we didn’t or couldn’t effect the timeline??
Knowing the effect of a function and actually how that function occurs are two different things. One cannot make the assumption that they understand why somethings happening simply because they can predict what’s gonna happen. I can tell you to pull the trigger on a firearm and the bullet will come out of the barrel, but if I tell you it’s because of magic. it happening every time doesn’t make it true
Back to the future #1 is right up there with the best movies of all time. Thank God they didn't base it on the science 😂
Sean Carroll has one of the most soothing voices ever. I genuinely love the topics, but it's so easy to just doze off while listening to him for an hour 😅
I don't feel like time actually exists. It can never be a minute from now; it will always just be now, no matter what the position of earth is to the sun. We're constantly moving now. How we age, I believe, depends on how well we look after ourselves. Things like growing, etc, happen because changes are constantly happening, now. Fuck, I'm really high.😂
if you want to go back on that couch and hit it again, i think i can change your mind. lemme just ask, do you remember computers way wayyyyy back like before windows 3.1? there was a button to play games that were from old CPUs, labeled _turbo_ that would take a game that ran at old processing speeds and have them run at half their speed for processors that ran twice as fast. now there is going to be a time when ai is close enough to conscience thought where a second is going to be an eternity and it will be running circles around our own thoughts. it will know exactly how many cycles away it is for one minute from now. couple that with the fact that the activity in your brain settles down before you reach a conclusion, meaning that before you are aware of it, your brain has made up it's mind and then it tells you the answer. a computer would be able to observe this and react in fewer cycles than it takes for you to come to the realization of your answer, so before you answer, it knows your answer. if that display of an answer happens before your aware, that computer has essentially moved backwards in time because it was fast. that means time exists.
i could be the high one...
Good logical thinking, you actually make more sense than most people on this thread.
The past doesn’t exist, the future doesn’t exist. That’s how symmetry works.
I want to go back in time to play gangsta rap from the 90's to hippies in the 1960s.
Time travel without relativity.
Time seems to be like an index that indicates what comes after/before/simultaneously in a change. It seems the only definition that makes sense in all situations. Your refrigerator is not a relativistic moving platform, but it is a time machine. You freeze a chicken andin 2 months you get older but the chicken come into your future as it was. Relativistically it should get older than you because it's atoms and molecules were going slower than yours which were vibrating at a higher temperature.
Are you getting dizzy?
It's one thing to achieve time jumps or connections through time and another talk about the paradoxes of time I'd like to know that the person speaking has some experience rather than just theoretical steering out of a window of what real people are doing in the real world
and then the james webb telescope was launched and it really put a damper on all the theories we had about the light cone of the universe. "we should see infant galaxies at the beginning" lmao!
At the cost of potential over simplification, do you mean:
Traveling through more space mean experiencing less time while experiencing more time mean traveling through less space?
The aether is real, it just lacks the properties first conceived. The higgs field is the aether.
Traveling through the aether you experience less time, though you may not know it.
Remaining motionless relative to the aether you experience more time.
This is the way I've thought about it for 20+ years, but I still don't know if it's correct.
If you throw a drone at the speed of light, filming behind it... Could you see the future?
Paradoxes would be the least of your worries.
Your biggest worry should be how do you survive in deep space and how do you get back to Earth after your time jump.
The Earth is moving...very rapidly...all the time.
And BTW, you would also still have the angular momentum and velocity that the Earth, the solar system and the galaxy had when you jumped.
Gravity as a fictitious force.
Main article: General relativity
The notion of "fictitious force" arises in Einstein's general theory of relativity. The way all masses in free fall descend at the same rate led Albert Einstein to wonder whether gravity could be modeled as a fictitious force. When F = ma, the size of the force can be measured by the size of the mass and how much the mass is being accelerated at. But all masses in free fall accelerate at the same rate of acceleration, that would mean if gravity is a force then that force changes for each object. He noted that a free falling observer along with various items in a closed box would not be able to detect any force at all, for they would all have no weight. W = mg then W zero = mg zero. In other experiments using a scale various items have various weights. Therefore now when using a scale F = ma is true, where equal acceleration truly produces different real weight forces from different masses, and F can now be measured; hence, weightless free falling reference frames are equivalent to force free inertial reference frames (the equivalence principle). Developing this insight, Einstein formulated a theory with gravity as a fictitious force, and attributed the apparent acceleration of free fall due to observers watching from a non-inertial reference frame while they are being accelerated by a force, and to the curvature of spacetime, which is a force free inertial reference frame. This idea underlies Einstein's theory of general relativity.
NIST WTC FAQ 31. How could the WTC towers collapse in speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?
NIST --> "Since the stories below the level of collapse initiation provided little resistance the building section above came down essentially in free fall."
@@davidmudry5622 Gravity is not a force, gravity is the effect that a mass has on space itself.
@@MichaelClark-uw7ex I said gravity does not pull but the official 9/11 explanation said the pull of gravity got stronger and stronger as each floor became part of the downward force.
@@davidmudry5622 That was a mistake, momentum increased as each floor pancaked, gravity is constant.
I'm pretty sure physicists know a lot more about gravity than the 9/11 commission
Teleportation is possible. It exists according to Andrew Basiago, he was involved in a secret Time travel/teleportation project in the early 70's ran by DARPA. It was called project Pegasus and experimented with Tesla Teleportation.
information about the past is still out there and if we manage to curve space time to travel faster than light we can travel in the past but we will only be there as observer
I time traveled to the end of this video when I woke up.
I dont think Time Travel will ever happen because noone has ever come back in time to tell us it exists!
Maybe there's a sort of "prime directive" about traveling to the past? As in, they've decided we, at this point in time, are not yet capable of handling that kind of information.
I disgree with time paradoxes. If you go back in time. It never happened before. Therefore it is new. Still a straight timeline. Therefore no paradox.
But if you go back and prevent your conception, how could you have travelled back to make the change?
Amazing talk
Time
Time seems to be like an index that indicates what comes after/before/simultaneously in a change. It seems the only definition that makes sense in all situations. Your refrigerator is not a relativistic moving platform, but it is a time machine. You freeze a chicken andin 2 months you get older but the chicken come into your future as it was. Relativistically it should get older than you because it's atoms and molecules were going slower than yours which were vibrating at a higher temperature.
Are you getting dizzy?
My time machine wasn't working so I took it to the repair shop. They told me to come back last Tuesday.
I thpught the title was "The President of Time Travel"
I was ready for a speech from our leader.
I discovered how to get around the paradoxes, but I will not share it.
90% of comment section: people who didn't listen and started typing 😂
Ok I was just traveling in time when this question came to me: nothing can go faster than light nor at the same speed. What about darkness? Every time you flick the light bulb off darknes closes in the same distance light can travel away from you at the same time. Each time the light is "off" darkness is totally "on" around you. What does this mean? What if is not light that is traveling at any speed, but darkness is. Is it a bad question? 😅 I'm obviously no physicist.
Don't listen to this man. His only purpose here is to confuse you! That is what the people in power want to do the general population today! Time is simply a measurement and nothing more! The other things that he is talking about are all illusions surrounding the concept of time, that don't really exist except in our mind. Even though yesterday feels like a real place, it doesn't really exist except in your mind. Yesterday's memories may be stored in your central nervous system and feel almost as real as what you are experiencing in the present but they have no reality beyond that! So try and understand that even the ideas about yesterday and tomorrow are happening only in the present, not the past or the future. They are only a measurement of how many times the Earth rotates on its axis and revolves around the Sun. All of these things are measured in one direction only. When you are asked how far you live from work you never say "minus 10 miles" do you? If you are asked when was the last time you went shopping, you don't say "minus 3 days ago" either, do you? Measurements are always positive because we live only in the present. Everything is judged from your present point of view. That is because that is all that is real. The rest is Memorex!
Reason, perception, philosophy...
all interesting, however, you are wrong about the non-existence of past events.
You should know, based on your statement, that there is NO time, as such, but we perceive it.
However, all events have/are taking place simultaneously.
'All time is now.'
It is not technically traveling anywhere in spacetime, not past, not future.
It is more of a dynamic shift of your perception.
You could see the other events, (which your perception say were in the past) BUT cannot affect them in any way as they are not really separated by time, but by perception.
All events have technically already happened. You are merely perceiving these events through the lens of your time perception.
The movie title 'everything, everywhere, all at once' was apropo, though the actual story did not portray the title's claim.
Yet it is accurate.
Everything - all perceived events- are happening now... now....now...
See?
Space is likely 5d, not 3d ... there are also the dimensions of inward and outward , inward being the microscopic and beyond, and outward being what we cannot detect because we are the microscopic in that case
Scaling refers to a change in the size or proportion of an object or space without changing its shape or structure. In an infinite space, scaling can occur in any direction or axis, but it does not necessarily create a new dimension. Instead, scaling changes the relative size of objects or structures within the space, but it does not fundamentally alter the number or nature of the space's dimensions.
While scaling can occur in an infinite space, it is not typically considered a dimension in the scientific sense.
The biggest paradox is... where are the time travellers? Its a bit like the fermi paradox but for time.