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.
People who want to travel back into the past are the same kind of people who get old, look old and trying to find means to be young and look young again. These people live miserable lives full of regret imo.
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.
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?
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.
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.
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.
Excellent lecture, thanks! A small inaccuracy about GPS though (33:26)....the receiver does not beam anything, it only passively receives signals....nor does it have any (accurate enough) clock to compare against....the received signals have encoded the time they were beamed and the position they were beamed from....given multiple available signals, the receiver's chip performs triangulation calculations to compute its own position.
The GPS receiver has a stable quartz clock. It constantly sets its time by using at least 4 satellites. By using at least 4, the overlapping signal spheres means it can pinpoint itself and calculate and correct for its own clock inaccuracy (because it can trust the satellite clocks) Therefore, all gps receivers are as accurate as an atomic clock. Otherwise, they would be very inaccurate
I think it's fascinating that we have to adjust the time on GPS satellites (in order to compensate for the relativistic effects of time dilation and frame-dragging), not because time is flowing any differently on-board the satellites, but because it _appears_ to be flowing differently from our perspective here on Earth. Relativity is weird!
@@simesaid We have grown up thinking time is unwavering- maybe in our experience we think it is, although 'time flies' is a great hint. Once you realise that the speed of light is fairly constant - and that different observers experience time _relatively_ which makes this true - it makes far more sense.
@@simesaid According to the experiment on an airplane flying around the earth time is really flowing different at a higher speed and different gravity. If it is time that is flowing different or the clock that is behiving different at speed is a question though in my oppinion. There is often two sides to a coin.
It is fascinating but with GPS we are talking micro seconds. When you get into the time dilation effects from near light speed travel that is when things get really interesting. Einstein's thought experiments were able to simplify mind boggling concepts. Then, he could math it.
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.
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?
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.
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
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.
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?
@@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
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
@David Mudry 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.
So we are moving thu space and time. Since every thing in the known cosmos is moving thu time and space. And always has. What would happen to an object or person if we stop them moving relative to the universe. Would it stop moving in time?
@@whichgodofthousandsmeansno5306 Absolutely it's impossible. we'd need to factor The size location and trajectory of every atom in the cosmos just for a reference point to start with. and that's not to mention that we don't know if the same sheet of time travels through multiple dimensions. and if we can stop relative to this dimension. that maybe its not gonna stop relative to another dimension. And in effect void any attempt to measure it.
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.
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?
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
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.
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.
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.
12:20 I take issue with you stating the idea that quantum mechanics "implies multiple worlds", since that is just one interpretation of quantum mechanics.
Since gravity can change the direction of space-time, what can the three other forces do? Can we have an effect on space-time by applying the weak or strong or electric-magnetic forces? What if all four were utilized simultaneously but at different angles and intensities? Could we precisely steer space-time?
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.
I've always wondered if Time Dilation accounts for the Fermi paradox. Beings in another galaxy travelling slower than we are, or with less gravity, would not have experienced as much time as we have, and wouldn't be as technologically advanced. So they wouldn't have mastered interstellar/intergalactic communication or travel.
34:35 hold up, I thought it was the immense speed that they were moving that affected the time dilation not the difference in gravity which would be negligible
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!
33:35 GPS receivers are called "receivers" because they only receive a signal from the satellite. They never send a signal to the satellite, that would be impossible because the satellites are 20000 kms away. No hand-held device could have the capability of sending a signal that far away.
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 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.
another video i watched some years ago(most likely a PBS Space time video) that put my mind at ease, solved the paradoxes by saying you dont really go in the past you only just create a copy of your current universe at the desired time and travel to it. so killing your parents really has no effect on you. edit: holly s*** it was this video. is this a reupload?
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??
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.
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.
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).
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.
I would think everything to do with theoretical physics is incomplete. My take is that multiverse theory solves all paradox. However, I see no way to verify it.
What if I went back in time and killed myself as a baby? If I did go back in time and killed my grandfather wouldn't that cause the time line to split causing an alternet time-line where I was never born but the time line I came from would continue on as if I never traveled back? Or would this time line be destroyed because there might be able to only have one time line.. No alts for some reson?
Sean who is this "we" you keep referring to? We don't know, is this we everyone you know or do the rest of us not count? Please be more specific. Thanks ✨️
That's what I was thinking. Since the solar system is revolving around the Galaxy the earth isn't where it was. So the time traveler would freeze in space until they burnt up on re-entering.
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...
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.
Surely everything you could possibly do, including e.g. breathing, would therefore not be possible, as even the most simple thing would have some effect on everything that happens after it.
I thought that at near light speed the time between observing the ship leaving from Earth and seeing it in front of you on Alpha Centauri could be arbitrarily short. With light taking zero time between observation and arrival. So it is true that the Earthling could reach Alpha Centauri in time for the Friday party if a near light speed autocraft is employed. I guess it depends on which "now" you accept when referring to things which happen on Alpha Centauri. It just seems impolite to refer to things on other planets happening "now" when we know that our observations are very old. * I think I am wrong. Anyone know where? I'm wondering why it is not sensible to call "now" on Alpha Centauri, the time at which light arrives when it leaves right now. Since all other now's are inaccessible. But if I send a message to Mars, I wouldn't say it arrived "right now" until 3 minutes after I sent it. So the "now" of anything is at least double what we can observe on their clocks from here. We see their clocks light distance behind and the soonest we can have any sense of being in the "now" on Alpha would be another light span of time. It makes no sense to call "now" on Alpha anything less, because we will never experience a "now" on Alpha any time sooner.
Backwards is not likely. First: how could you ever slow time beyond completely stopped? And I don't see any way of even slowing time slower than the constant pace everything moves at. Even if something is moving along the timeline slower than you, how could you reduce your speed not only to match it but actually travel slower? Now I'm talking "light speed" if indeed it could be done, however we do know that, the faster a object of mass moves the more massive it becomes... these are real serious and as of now and probably forever will remain impassable obstacles, if we choose speed and momentum as our field of experimentation. But what about electromagnetic energy?
I think the closet that some of us will get to Time Travel will be a computer generated version of reality, maybe a Virtual Reality machine of sorts like a holodeck or something, where points in time, although possibly arbitrary, could be generated for people to see. The way computer tech is advancing, this is not beyond possible in te next 50 years.
and maybe they'll be able to create a perfect simulation of our time that people will get plugged into. and maybe people inside this simulation forget that they're in one. and they create simulations of their own. which eventually create simulations of their own...and so on ;]
I do have a legitimate question though; I thought that all that is, all that was, and all that will be exists within a state akin to omnipresence? Meanwhile, something with a consciousness is "railed in" to percieve at a limited rate, in its limited space, while the rate at which that being percieves time is dependent on its speed through that-which-has-already-taken-place? I am sorry that I can not write this to be more clear.
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 😊
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.
Time travel forward= to go about things through out your day in the most efficient and correct way possible puts you ahead of any other that has to rework something because they had to redo something.Time travel back=failure lack of completion of a process ,unforseen ,refuse help,forgiveness,distruction
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.
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.
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
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!
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?
Is it considered a time travel paradox if a person is reincarnated into their previous self, but they lose most future knowledge each time that happens?
Since telescopes like Hubble and James Webb can look billions of light years away and see the light reflected from objects as they were at that time, billions of years ago; I'm wondering is it possible to point the telescope to two different locations where an object has been and see the same object at two different times? Its hard to wrap my head around this one. When I look at that now famous picture with all of the galaxies in It, who is to say one of those galaxies is also one we've taken now closer to us and older.? Sooo can we look back toward the center of the universe and see our own galaxy billions of years ago? That being said have you ever tried to reconstruct what we see in the sky at night, since it represents an illusion of many times, and ages, in the past, to what or how each object looks or really exists in this moment? What trends do you think that would show different to what we see now? For example TCRB would be long gone maybe positioned somewhere else? Betelgeuse might already be a supernova? How much does this relationship of what we can see right now matter, compared to what state the things we see are actually in right now? Thank you for considering these questions!
Astronomers HAVE seen the same object (a galaxy) at multiple different times by using gravitational lensing. They had predicted a supernova flash on one of the lensed images that would occur about a year after the original sighting was seen in one of the other lensed images. Wicked awesome. ( and of course they were ready and waiting for the second appearance with all the measuring instruments they could spare).
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.
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?
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?
Why do so many web pages have the word "time" on them? I wager it's because a lot of pages have footers that say things like "time stamp: xxx" So googling and counting is not a very scientific thing for a scientist to do. I was going to do some tests but apparently google no longer gives the number of results.
2:40 Almost a "trillion"? Or merely a billion? EDIT: got the correction. 12:00 Universes split off when a quantum system is measured? How often does that happen, given that we continuously look around and see things? I suppose the number of splittings reflects the probability of a particular measurement. For example, measuring a two-state system would cause the universe to split in two if the amplitudes were the same. But if the amplitudes were, say, 20/29 and 21/29, the universe would spit into 841 universes. How many universes would we have if the amplitudes were irrational but between (say) 1/sqrt(2) - 10^-12 and 1/sqrt(2) + 10^-12. For that matter, sometimes a measurement fails. Maybe the universe splits into several universes in which the universe split, and other universes in which the universe didn't split. 21:10 Einstein invents special relativity? Omitting work of Lorentz, Fitzgerald, Voigt, and others?
@@leonhardtkristensen4093 Every time a universe splits off, a new universe of energy is created? There's one hypothetical possibility, maybe: including gravitational potential energy, the total energy of each universe might be zero.
@@leonhardtkristensen4093 "Come from" is impossible to answer with our current knowledge. However, the JWT seems to be casting doubt on BBT. It is implying the universe is the same no matter how far back we search. Has me thinking eternal. But we still have a ways to go.
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
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.
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.
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
My question is, why Positive particles is attracted to and interact with dark energy & dark matter? At the Same-time can the same thing happened to the negative particles? For example; let’s say the opposite happened: hypnotically light energy and light matter that maybe attracted to and can interact with negative particles? Hence, Why there’s no annihilation within the two, positive and negative particles? Simple hypotheses is, dark energy and dark matter maybe/can be repulsive to light energy and light matter, (like opposite poles in a magnet) and if they do touch why you get part of space in our Universe becomes a cold spots?!? Hence reason why the Universe didn’t cancel itself out?!? Meaning there’s the possibility of two Universes? One with positive particles that can only interact with dark energy & dark matter, which in-turn another Universe in-which negative particles is attracted to and interact to light energy & light matter?!? The Black hole which is abundant in our Universe but white holes are rare Vice-verse White holes maybe abundant in the Negative Universe but black are rare?!? Also why there’s some negative particles is still in our Universe? Well it can happen in the Opposite Universe which white holes are abundant in which the negative particles can only leak through to our Universe through our Black holes? Vice-verse our positive particles goes through a black holes comes out through the negative Universe white hole? Into an inter-Universal vice-versa! Evidence when NASA discovered negative neutrinos coming out of the earth core through Antarctic into space?!? Maybe why our Universe can only go forward in time and cannot reverse time vice-verse in the negative universe time can only go reverse but not forward?!? Which means a new physics has to be applied?!?
Dark energy and dark matter are still yet to be found. You are asking question that theoretical physicists have been trying to figure out for a century. Maybe the JWT will help answer some. I am sure it will make headlines.
A lot of the stuff I’ve heard about the way UAPs function is that they have the ability to manipulate gravity, and I’ve also heard the theory that whoever is controlling them may be from the future even humans from the future. So if what this guy is saying is That with a sufficient gravitational force time travel to the past is possible, it seems like that could be what these UAPs are able to do if the gravity manipulation theory is true
It seems to me that "time" is the one word in human language that cannot be properly defined. Trying to define time always seems to result in circular reasoning or in using its own units or its characteristics such as past, present or future when attempting to define time. I have always believed that time can only be experienced but never truly defined.
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
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!
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 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.
Did it ever dawn on you that you actually did fall asleep but then went back in time and watched it?
@ZZSmithReal help
Sean Carrol makes you go asleep if you listen to him so much that you know exactly what he’s going to say. That’s how I get to sleep.
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?
He has Perrier I gave him. Issue is the bartender forgot the glass and he didn't want to drink out of the bottle
People who want to travel back into the past are the same kind of people who get old, look old and trying to find means to be young and look young again.
These people live miserable lives full of regret imo.
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 made a travel back in time in the year 2010 and was able to see a conference of S. Carrol...
On UA-cam 😂
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?
I wish UA-cam 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.
Excellent lecture, thanks! A small inaccuracy about GPS though (33:26)....the receiver does not beam anything, it only passively receives signals....nor does it have any (accurate enough) clock to compare against....the received signals have encoded the time they were beamed and the position they were beamed from....given multiple available signals, the receiver's chip performs triangulation calculations to compute its own position.
The GPS receiver has a stable quartz clock. It constantly sets its time by using at least 4 satellites. By using at least 4, the overlapping signal spheres means it can pinpoint itself and calculate and correct for its own clock inaccuracy (because it can trust the satellite clocks)
Therefore, all gps receivers are as accurate as an atomic clock. Otherwise, they would be very inaccurate
I think it's fascinating that we have to adjust the time on GPS satellites (in order to compensate for the relativistic effects of time dilation and frame-dragging), not because time is flowing any differently on-board the satellites, but because it _appears_ to be flowing differently from our perspective here on Earth. Relativity is weird!
@@simesaid
We have grown up thinking time is unwavering- maybe in our experience we think it is, although 'time flies' is a great hint. Once you realise that the speed of light is fairly constant - and that different observers experience time _relatively_ which makes this true - it makes far more sense.
@@simesaid According to the experiment on an airplane flying around the earth time is really flowing different at a higher speed and different gravity. If it is time that is flowing different or the clock that is behiving different at speed is a question though in my oppinion. There is often two sides to a coin.
It is fascinating but with GPS we are talking micro seconds. When you get into the time dilation effects from near light speed travel that is when things get really interesting. Einstein's thought experiments were able to simplify mind boggling concepts. Then, he could math it.
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.
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
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.
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
22:44 at what moment does the traveling clock start to differ from the stationary clock?
the moment one clock travels a different distance
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
14:20. If you can't change your timeline because it already happened, why can you change another realities past when that also already happened?
because that happened, you didn't change it, you contributed to it
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
@David Mudry 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.
@David Mudry Virtually none until the drones hit a passenger, a seat or the bus windshield.
@David Mudry Newton also invented calculus, so if you think that he was an idiot, I have nothing more to say to you.
Science does not answer all questions of life… if there is no objective reality, than we can’t make sense of anything in this universe..
So we are moving thu space and time. Since every thing in the known cosmos is moving thu time and space. And always has. What would happen to an object or person if we stop them moving relative to the universe. Would it stop moving in time?
Good question. I can't think of a way to stop moving though. It might be impossible.
@@whichgodofthousandsmeansno5306 Absolutely it's impossible. we'd need to factor The size location and trajectory of every atom in the cosmos just for a reference point to start with. and that's not to mention that we don't know if the same sheet of time travels through multiple dimensions.
and if we can stop relative to this dimension.
that maybe its not gonna stop relative to another dimension.
And in effect void any attempt to measure it.
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?
The Spielberg movie he was talking about was Interstellar. It was going to be Spielberg before Nolan took over. Very cool.
what about spooky action at a distance, light cones violated, please explain
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
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.
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
Bla bla bla.
Proof that he will present anywhere. Kudos.
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.
12:20 I take issue with you stating the idea that quantum mechanics "implies multiple worlds", since that is just one interpretation of quantum mechanics.
Since gravity can change the direction of space-time, what can the three other forces do? Can we have an effect on space-time by applying the weak or strong or electric-magnetic forces?
What if all four were utilized simultaneously but at different angles and intensities? Could we precisely steer space-time?
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.
2x playspeed is too slow, youtube needs a faster 4x, or some other paradoxical speed.
Though 38:17 at 0.25x is too much if not sober.
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.
I've always wondered if Time Dilation accounts for the Fermi paradox. Beings in another galaxy travelling slower than we are, or with less gravity, would not have experienced as much time as we have, and wouldn't be as technologically advanced. So they wouldn't have mastered interstellar/intergalactic communication or travel.
34:35 hold up, I thought it was the immense speed that they were moving that affected the time dilation not the difference in gravity which would be negligible
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!
33:35 GPS receivers are called "receivers" because they only receive a signal from the satellite. They never send a signal to the satellite, that would be impossible because the satellites are 20000 kms away. No hand-held device could have the capability of sending a signal that far away.
Satellite Phone?
@@brettjunge5545 Communication satellites are only a few hundred kilometers of altitud, not tens of thousands.
UA-cam: hey wanna hear a guy talk about time travel for an hour?
Me: where you been all my life?
How do we know the black holes created are not portals into other dimensions- through time??
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.
Very interesting. Great lecture!
Speed of lite or speed of perception?
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.
The cadence of nervous academics giving talks should be harnessed to power interstellar vehicles.
How much energy was captured per cubic centimeter?
Doesn't space expand faster than light in order for light to pass?
another video i watched some years ago(most likely a PBS Space time video) that put my mind at ease, solved the paradoxes by saying you dont really go in the past you only just create a copy of your current universe at the desired time and travel to it. so killing your parents really has no effect on you.
edit: holly s*** it was this video. is this a reupload?
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??
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.
You went back in time for that?
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?
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).
Two pair of doxes walk into a bar. Bartender says get out.
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.
Are theories that do not exclude true timetravel (relativistic timetravel or "timetravel" is alright) just incomplete?
I would think everything to do with theoretical physics is incomplete. My take is that multiverse theory solves all paradox. However, I see no way to verify it.
What if I went back in time and killed myself as a baby?
If I did go back in time and killed my grandfather wouldn't that cause the time line to split causing an alternet time-line where I was never born but the time line I came from would continue on as if I never traveled back? Or would this time line be destroyed because there might be able to only have one time line.. No alts for some reson?
Sean who is this "we" you keep referring to? We don't know, is this we everyone you know or do the rest of us not count?
Please be more specific.
Thanks ✨️
I travelled 8 hours ahead in time when my alarm clock went off
If someone can travel backwards in time, will there be anything there?
That's what I was thinking. Since the solar system is revolving around the Galaxy the earth isn't where it was. So the time traveler would freeze in space until they burnt up on re-entering.
I travel back in time when I'm laying in bed trying to fall asleep.
What about the Langoliers?
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...!!
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
And four years after this lecture, Nolan and Kip came out with Interstellar.
Interstellar is a science fiction movie.....the operative word being fiction.
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.
Surely everything you could possibly do, including e.g. breathing, would therefore not be possible, as even the most simple thing would have some effect on everything that happens after it.
Go in the reverse and it’s the same.
I thought that at near light speed the time between observing the ship leaving from Earth and seeing it in front of you on Alpha Centauri could be arbitrarily short. With light taking zero time between observation and arrival.
So it is true that the Earthling could reach Alpha Centauri in time for the Friday party if a near light speed autocraft is employed.
I guess it depends on which "now" you accept when referring to things which happen on Alpha Centauri. It just seems impolite to refer to things on other planets happening "now" when we know that our observations are very old.
* I think I am wrong. Anyone know where? I'm wondering why it is not sensible to call "now" on Alpha Centauri, the time at which light arrives when it leaves right now. Since all other now's are inaccessible. But if I send a message to Mars, I wouldn't say it arrived "right now" until 3 minutes after I sent it. So the "now" of anything is at least double what we can observe on their clocks from here. We see their clocks light distance behind and the soonest we can have any sense of being in the "now" on Alpha would be another light span of time. It makes no sense to call "now" on Alpha anything less, because we will never experience a "now" on Alpha any time sooner.
Backwards is not likely. First: how could you ever slow time beyond completely stopped? And I don't see any way of even slowing time slower than the constant pace everything moves at. Even if something is moving along the timeline slower than you, how could you reduce your speed not only to match it but actually travel slower?
Now I'm talking "light speed" if indeed it could be done, however we do know that, the faster a object of mass moves the more massive it becomes... these are real serious and as of now and probably forever will remain impassable obstacles, if we choose speed and momentum as our field of experimentation. But what about electromagnetic energy?
Okay the 2word phrase (time travel),might be a bad choice of words to describe what has all ready happened,??
I think the closet that some of us will get to Time Travel will be a computer generated version of reality, maybe a Virtual Reality machine of sorts like a holodeck or something, where points in time, although possibly arbitrary, could be generated for people to see. The way computer tech is advancing, this is not beyond possible in te next 50 years.
and maybe they'll be able to create a perfect simulation of our time that people will get plugged into. and maybe people inside this simulation forget that they're in one. and they create simulations of their own. which eventually create simulations of their own...and so on ;]
Don't hold your breath. People have been working on Fusion power for well over 70 years and its still just a dream.
I do have a legitimate question though; I thought that all that is, all that was, and all that will be exists within a state akin to omnipresence? Meanwhile, something with a consciousness is "railed in" to percieve at a limited rate, in its limited space, while the rate at which that being percieves time is dependent on its speed through that-which-has-already-taken-place? I am sorry that I can not write this to be more clear.
What about Hawking radiation that supposedly escapes black holes?
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.
If it is the expansion of the universe that creates the arrow of Time, would you not have to shrink the universe to go back in time?
If time travel will ever exist it would always have existed.
Time travel forward= to go about things through out your day in the most efficient and correct way possible puts you ahead of any other that has to rework something because they had to redo something.Time travel back=failure lack of completion of a process ,unforseen ,refuse help,forgiveness,distruction
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
That is unless their truth is suppressed and they disappear. Sounds familiar doesn't it?
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."
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
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!
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?
I love this man. He is so knowledgeable and speaks clearly.and honestly.
He makes physics entertaining.
Glad he doesn't mumble and lie .....
Is it considered a time travel paradox if a person is reincarnated into their previous self, but they lose most future knowledge each time that happens?
Since telescopes like Hubble and James Webb can look billions of light years away and see the light reflected from objects as they were at that time, billions of years ago; I'm wondering is it possible to point the telescope to two different locations where an object has been and see the same object at two different times? Its hard to wrap my head around this one. When I look at that now famous picture with all of the galaxies in It, who is to say one of those galaxies is also one we've taken now closer to us and older.? Sooo can we look back toward the center of the universe and see our own galaxy billions of years ago? That being said have you ever tried to reconstruct what we see in the sky at night, since it represents an illusion of many times, and ages, in the past, to what or how each object looks or really exists in this moment? What trends do you think that would show different to what we see now? For example TCRB would be long gone maybe positioned somewhere else? Betelgeuse might already be a supernova? How much does this relationship of what we can see right now matter, compared to what state the things we see are actually in right now?
Thank you for considering these questions!
Astronomers HAVE seen the same object (a galaxy) at multiple different times by using gravitational lensing. They had predicted a supernova flash on one of the lensed images that would occur about a year after the original sighting was seen in one of the other lensed images. Wicked awesome. ( and of course they were ready and waiting for the second appearance with all the measuring instruments they could spare).
Time is the Movement of an object within a given Space .
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.
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?
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?
Why do so many web pages have the word "time" on them? I wager it's because a lot of pages have footers that say things like "time stamp: xxx"
So googling and counting is not a very scientific thing for a scientist to do.
I was going to do some tests but apparently google no longer gives the number of results.
2:40 Almost a "trillion"? Or merely a billion? EDIT: got the correction.
12:00 Universes split off when a quantum system is measured? How often does that happen, given that we continuously look around and see things? I suppose the number of splittings reflects the probability of a particular measurement. For example, measuring a two-state system would cause the universe to split in two if the amplitudes were the same. But if the amplitudes were, say, 20/29 and 21/29, the universe would spit into 841 universes. How many universes would we have if the amplitudes were irrational but between (say) 1/sqrt(2) - 10^-12 and 1/sqrt(2) + 10^-12.
For that matter, sometimes a measurement fails. Maybe the universe splits into several universes in which the universe split, and other universes in which the universe didn't split.
21:10 Einstein invents special relativity? Omitting work of Lorentz, Fitzgerald, Voigt, and others?
Also has any body thought about that all the matter in the universe is really energy. My question is then where does all that energy come from?
@@leonhardtkristensen4093 Every time a universe splits off, a new universe of energy is created? There's one hypothetical possibility, maybe: including gravitational potential energy, the total energy of each universe might be zero.
@@leonhardtkristensen4093 "Come from" is impossible to answer with our current knowledge. However, the JWT seems to be casting doubt on BBT. It is implying the universe is the same no matter how far back we search. Has me thinking eternal. But we still have a ways to go.
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
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.
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.
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
this dude again
Amazing talk
My question is, why Positive particles is attracted to and interact with dark energy & dark matter? At the Same-time can the same thing happened to the negative particles? For example; let’s say the opposite happened: hypnotically light energy and light matter that maybe attracted to and can interact with negative particles? Hence, Why there’s no annihilation within the two, positive and negative particles? Simple hypotheses is, dark energy and dark matter maybe/can be repulsive to light energy and light matter, (like opposite poles in a magnet) and if they do touch why you get part of space in our Universe becomes a cold spots?!? Hence reason why the Universe didn’t cancel itself out?!? Meaning there’s the possibility of two Universes? One with positive particles that can only interact with dark energy & dark matter, which in-turn another Universe in-which negative particles is attracted to and interact to light energy & light matter?!? The Black hole which is abundant in our Universe but white holes are rare Vice-verse White holes maybe abundant in the Negative Universe but black are rare?!? Also why there’s some negative particles is still in our Universe? Well it can happen in the Opposite Universe which white holes are abundant in which the negative particles can only leak through to our Universe through our Black holes? Vice-verse our positive particles goes through a black holes comes out through the negative Universe white hole? Into an inter-Universal vice-versa! Evidence when NASA discovered negative neutrinos coming out of the earth core through Antarctic into space?!? Maybe why our Universe can only go forward in time and cannot reverse time vice-verse in the negative universe time can only go reverse but not forward?!? Which means a new physics has to be applied?!?
Dark energy and dark matter are still yet to be found. You are asking question that theoretical physicists have been trying to figure out for a century. Maybe the JWT will help answer some. I am sure it will make headlines.
A lot of the stuff I’ve heard about the way UAPs function is that they have the ability to manipulate gravity, and I’ve also heard the theory that whoever is controlling them may be from the future even humans from the future. So if what this guy is saying is That with a sufficient gravitational force time travel to the past is possible, it seems like that could be what these UAPs are able to do if the gravity manipulation theory is true
It seems to me that "time" is the one word in human language that cannot be properly defined. Trying to define time always seems to result in circular reasoning or in using its own units or its characteristics such as past, present or future when attempting to define time. I have always believed that time can only be experienced but never truly defined.
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
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