Neil deGrasse Tyson’s Guide To Time Travel - StarTalk 101

[@StarTalk]

If you could travel in time, where or when would you go?

[@hallogeen4580]

Meet Albert Einstein

[@powertothesheeple5422]

To the absolute very begining, set the clock to 0:00

[@08mario08]

Make myself rich by making the right investments😅

[@markopazin9912]

2 seconds in the future

[@michaelccopelandsr7120]

That depends, is it a one way trip or are we just visiting?

[@LTDunltd]

The other side of the The Grandfather Paradox. Look at Fry from Futurama. Another time travel paradox. You travel 30 years into the future to visit yourself only to find out you've been missing for the past 30 years.

[@lllllRoguelllllX]

Wait a min….

[@mariotaz]

....wait

[@stormchaser7992]

Terminator The Sarah Connor Chronicles did this. A younger John Connor traveled into the future after the war had started and no one knew who he was.

[@cooksburg]

I would go back and make my parents fall in love.

[@markstriker925]

Seinfeld music plays.

[@usnluna1395]

I love the idea that no matter what you do in the past, it will not change anything. You go back and change something in history, return back to your original time. When you get back to your original time you notice nothing has changed because what you went back into the past has already happened before you left, because you left back in time to change it.

[@usnluna1395]

I don't think I worded that properly for someone else to understand as I believe it in my head

[@OneEyed_Jack]

That's always been how I see it. Anything you went back and do already happened the first time around, so nothing changes. Any changes are doomed to failure. They won't happen because they didn't happen.

I like the idea that even if you changed anything significant, you'd never be able to return to your original timeline...you only affected change to the timeline you messed with. You however are entwined with your own timeline from where you departed, that's why you'd not see the change.

[@izzycrybaby1164]

Yeah only problem is, if nothing changed, then there would be a present you still there at your time where you no longer belong.

[@ToberWilson]

That is called causality

[@DodgyDaveGTX]

I love how Neil constantly retells the same anecdotes, examples, or analogies when explaining a point to someone different each time but always with a consistent level of enthusiasm and chuckling.

[@abiofficial-ws7pn]

Two channels I love, have uploaded videos related to time travel on the same day. Science Asylum, and Star Talk.

[@michaelcalder8431]

Brian May of Queen wrote a song about this many years ago. It's called 39 and it brings a tear to your eye...

[@VisibletoanyoneonYoutubes]

Thank you for your comment. You are divine and inherently loved.❤

[@PureElectron]

​@@VisibletoanyoneonKZbins😊😊

[@DodgyDaveGTX]

@@VisibletoanyoneonKZbins Aww, but _I_ wanna be divine and inherently loved ☹

[@zaxko86]

Found Star Talk by accident and love it. Within a week I was surprised to see him on Big Bang Theory and then Brooklyn 99 to help Gina. Terry might be buff but I believe he's much stronger than Terry. Charles cracks me up. I think there the power couple of astrophysicist even though chuck isn't one I believe. Would love to see Neil at a show around Florida. Both are great and plan on listening to this channel at work. Work sucks but both make me feel smart while working.

[@DodgyDaveGTX]

>"Found Star Talk by accident" No my friend, Star Talk found you 😉

[@zaxko86]

@@DodgyDaveGTX You are right it did find me. I was listening to anton petrov channel at work with autoplay on and one of his videos started that's when I got hooked. I love the chemistry of the two and the subjects. They make me feel smarter the way they explain it that I can understand stand it.

[@FutChamps17]

Dude Neil is a genius! His knowledge of astrophysics is amazing. I’m literally doing a massive project and essay on his impact on society! Keep it up 🤩

[@Zurpanik]

Two ideas about not seeing time-travelers in our time now: 1) Perhaps there is some unfolding of the future universe which will allow through its expansion backwards time-travel, but since we live in a time with no time-travelers we can imagine that such a change has not happened yet and so cuts off access to our time now from in the future, or 2) since we do not have relativistic-velocity vehicles or craft, any time-travels that DO visit us, would be STUCK! They'd not be able to return to the future -- In one or both of these ways there might be a kind of "time horizon" where the time we find ourselves in now simply cannot support or does not make it a good idea to visit us from the future. Love this stuff!

[@HelpMeFindTheseSongs]

Or possibility #3: Time travel is only possible when time travel is discovered. In order to teleport, for example, you need a Pod A that you enter into, and a Pod B that you exit from. Same with time travel. There is currently no Pod B invented yet, therefore a future time traveler will not be able to enter their Pod A and travel back in time to us. Time travel to the past will only be possible to go as far back as the day Pod B was invented. Does that make sense?

[@californiacloud1036]

Or they are uap’s. Time travel would have to remain secretive, for obvious reasons.

[@thisbushnell2012]

Perhaps in the future, mankind grows up enough to stop wanting to monkey with history.

[@Vicki-Paz]

i love neil sm, i can listen to him for hours

[@spazbog123]

I have already traveled back in time. I flew from Australia to the US and I arrived in the US on the same day I left but it was earlier in the day than when I left. Only a few hours before I left but I also traveled for 17 hours. I would not advise trying to travel back in time the other way around though, you will wind up in the future.

[@BenjySparky]

Neil and Chuck, y'all rock! Peace

[@MegaDeano1963]

It's good to see the great thinkers of the world , looking at the pressing problems , truly humbling.

[@jurisauzins9266]

Just a thought - Given that we have a telescope powerful enough, and if we would place a mirror large enough far enough, it should be possible for us to see the earth in the past. So a mirror 1Ly away would show 2 years in the past and so on.

[@AdmiringObserverR]

Yes. But people would only be able to see as far back as when the mirror was first installed.

[@TorQueMoD]

I love the last one the most where Neil is talking about the 5th dimensonal scenes in Interstellar. Really cool :)

[@norcalpacific]

THIS IS an OLD RE-UPLOAD. You should be putting that in the description to let people know the original date.

[@joe12d]

How old exactly?

[@joe12d]

He said Google+ 😂 it’s OLD

[@bentucker2301]

They time travelled

[@branndoncaffy5175]

Yeah give me my free stuff just how I want it

[@hme850]

Also the fact that he mentioned Dr Strange moving through space but not time. This is clearly pre-Endgame.

[@sjw4life546]

I get the fascination among alot of people to use time travel to go to the past, but as a black man with knowledge of history, I'm not as keen on going to the past, im using them tachyons to travel to the future to see if we've progressed past the bullcrap of the present and past culturally, to see the advancement in technology and medicine etc.

[@moonshoes11]

When is Gamora?

[@joe12d]

I’ll do you one better. Why is Gamora?

[@warrengouldthorpe5091]

I'll do you one better, What is Gamora?

[@TRVPHAUS]

I'll do you one better, WHERE is Gamora?

[@moonshoes11]

Nobody asks…How is Gamora? ;)

[@Ben-Ken]

J G Levitt is in some of my favorite movies. He picks great projects.

[@ziggy_425]

Something interesting that was brought to my attention recently...if you travel back in time, you would have to account for the space in which the earth has traveled since. So if you travel back to the 1950s you would just land in empty space because the earth was in a different location around the sun from when u first traveled

[@geraldineclarke5434]

I am SO grateful to StarTalk for helping me to learn the science that I should have learned in school but this episode reminds me of theologians discussing how many angels could dance on the head of a pin.

[@clericstorm2009]

It's called StarTalk not StarDissertation

[@shellsel]

I just want to know when déjà vu occurs or jamais vu, could that your future or past self interfering with your own timeline (from the 5th dimension or higher) and that's the residual memory (for deja vu) or non-memory (jamais vu) of it still being there for your current "present" self? I wonder if my past/future self is messing with me (intentionally or not) when these things occur lol

[@invalidletterdept2662]

If you think about it, you can’t be responsible for your own dejavu (spelling I know). If you do something to affect past you, isn’t that just you being aware of what your past self felt and you’re currently acting on it? (For example traveling somewhere you’ve been before so that past you can feel like they’ve been there before. And if you do something to give your future self dejavu, isn’t that just a memory?

[@shellsel]

@@invalidletterdept2662 oh interesting 🤔 I will have to think about this further (im all out of my thinking capacity for now lol). Tbh I was just throwing around random ideas before when I made my original comment. But I will chew on what you've said. And thank you for your thoughtful reply 😊

[@acedoesntgame2204]

Here's what I think about deja vu. You're in a situation where it is similar to the past but forgot, so your memory is kind of blurry about whether this has happened yet or not, so you think that it probably has happened in the past. It is either you have actually been there but forgot, dreamt about it, or saw it online.

[@stephown5374]

The problem with going back in time is that the planets are in perpetual motion, the location you would have to go to is a point in space that we no longer occupy or can reach. This is actually the same if you could go forward in time. Another way to think about time is to think of the light coming from other stars that we observe. If you could travel along the path that light is taking, (as if it were frozen but you could move along it) you could observe the light at various points in the time that it has recorded from the time it left its source to the final point when it hits the lens of an observatory.What we observe on earth is not a representation of the actual current state of the source point at the time we see it. We are seeing a constant march of light representing the various states in the distant past of the actual source. So technically, if we went far enough away from our sun, we could see into our past. Just need a wormhole to be able to go collect the data.

[@robr177]

Travelling backwards through the dimension of time alone is impossible, even theoretically. You would only be able to move through spacetime. That means every bit of matter would be back in the position it was in during that time. That's why you would never be able to observe light like that.

[@robinbrowne5419]

With wormholes, black holes, time travel, past siblings, past grandparents, past you, future you, mating in the past, mating in the future, alternate kids, alternate realities, time lines, terminators, tachions, variable time, the speed of light, messages from the future, messages from the past, messages from far far away, loops and folds in time, loops and folds in space, 4 dimensional space-time, time machines, journeys in time, can things get any weirder?

[@izzycrybaby1164]

The faster you go the slower time passes for you. Imagine you start accelerating toward lightspeed, your atoms slow, at lightspeed they stop, beyond lightspeed your electrons start to orbit your atoms' nuclei in the opposite direction. You are going back in time. Now, having atoms that move in reverse should hypothetically be antimatter particles. In that case, shouldn't that person be instantaneously annihilated when their negative matter meets positive matter? Seems like thatd be a pretty simple way for the universe to correct the issue of mortals trying to break its laws

[@lucianocisneros805]

This sounds like a very good statement yes, but that only would apply if you, physically you, would be "running" at lightspeed, your body, literally. I don't think that if we ever do reach lightspeed, our bodies would be the ones to do it, I'm thinking maybe a vessel of some type, a ship of sorts. Just like astronauts leave our atmosphere at burning speeds, and preserving life inside from any danger the universe might present to human bodies, like asteroids or lack of oxygen you name it, it would be a ship that would endure the laws of physics and the universe! not our bodies. We've already broken the laws of the universe the moment we left our homeplanet to visit the stars! :O

[@SydMountaineer]

Stargate - my favorite movies & tv series.

[@QuestHuntersGaming]

I love startalk so much I don’t mind listening 24H

[@lovelywaz]

"If you could travel in time, where or when would you go?" My biggest issue would be "HOW" would I get to the "Exact SAME place" in past/future time. Since we know for a fact that our planet Earth is orbiting Sun and Sun is orbiting around the center of Milky Way and our Galaxy is ALSO moving in the space at the speed of about 600 KM/s. If you want to go a year in the past, where would you "land"? Earth will NOT be exactly at the same spot that you were currently when entering into whatever tunnel/portal and coming out a year in the past.

[@secretarts]

So in this conversation about time travel, how do you allow for location of the spot you are traveling to at the time of leaving to the place it would have been when you left? IE: to move from say the surface of earth, to go back in time just 1 hour to the exact same spot you leave from, the earth moved in the least 1000 miles in X-axis + at the least 2800 miles in Y-axis + another 40000 miles on the Z-axis because earth is not just sitting still in relationship to where you started, and if the location is some where else well that adds another 4-dimentional maybe more to the problem of locations.

[@potchirocksPH]

I think it depends on the frame of reference. If it is in the frame of reference of the person that time traveled, then everything relative to him did not change location.

[@rwarren58]

We are talking about moving across galactic distances. Since you would arrive in a ship within the system, you can simply fly the rest of the way. You weren't thinking of Quantum Leap traveling, were you?

[@jimlaz7456]

Been watching donut for like 2 hrs, thanks for snapping me out of it! If I could time travel I'd get those hours back.

[@jimlaz7456]

@RenataKleinRK donut media; KZbin channel, mostly car stuff, fails etc. nothing cerebral.

[@rezadaneshi]

The timeline I travel to and make any changes is traveling to it's future at the same speed of time, as the timeline that I left; those two timelines will never intercept for my changes to reflect on my original timeline

[@danielspahn2593]

We are all time travelers, we just travel one way

[@AzeAlter]

The end of '12 Monkeys' is a great way of seeing time travel.

[@FulcrumGhost]

LOVE StarTalk! Thank you Neil!

[@SydMountaineer]

Sadhguru said something about space & time not being differentiated from each other, in I think, the older or current Hindu language - that there was/is just one word that meant/means both. So, maybe space & time aren’t different things??? Sadhguru also points out that the only reality is the present, the past is memories in our minds, and the future is fantasy, which is also in our minds - this makes the most sense to me when thinking of time and space, together as one.

[@DIPANKARROY-jw7pc]

I don't want to change anything, but just to enjoy again that first kiss... ❤

[@ACrowNamedPoe]

In Futurama, Fry did the nasty in the pasty and became his own grandpa 😆

[@deepelements]

KZbin is like a time machine. We can go back and see that Neil was already awesome at a young age

[@MathewSan_]

Great video 👍

[@JamesCarty-m8f]

The theory introduced at 9:05 was included in the sci-fi book/series 11.22.63. It was interesting as the author mentioned the past does not want to change.

[@mr_tw]

A thought just popped into my head… There is an argument that time travel to the past is not possible, because if it ever gets invented in the future, it will become available for all time, and therefore we’d already know about it because some wise guy from the future will have told us. But what if it may be possible, but just unstable… so any attempt to go back in time becomes erased from spacetime… or history… or this version of the Multiverse etc. Just a thought.

[@PatMaddox]

What’s the movie they were talking about at 7:18?

[@mattjw16]

I would like to know this too! (I am writing this reply so I get a notification when someone answers 😊)

[@jrj2820]

11:54 I think those text are what we call Deja vu . Reason we are to pay close attention when we get them

[@omerdogruyol7984]

Time travel is like opening your eye and receiving light spectrum and turning that to an image and seeing it as it was

[@fugazinemesis]

I have a question about approaching the speed of light. If you move towards the speed of light time slows down. What happens when you slow down from the speed of light? If I stand on a train and walk forward then I am traveling faster than the train. I don't get to my destination any sooner though other than the length of the train. I you travel as fast as light time slows down but surely when you come to a stop time has caught up. If it's taken an hour to travel everywhere in the universe would have only moved an hour too. You've just arrived there faster?

[@richardfurness7556]

It's your speed that causes time to run more slowly. Whether you're speeding up or slowing down doesn't matter, you're still travelling faster than you would have done if you'd stayed on Earth.

[@fugazinemesis]

@@richardfurness7556 If you walk to the shops time goes by (say 15 mins), if I run less time is spent (say 5 mins). The world and the universe only 'travelled' either 15 mins or 5 mins in either case. It doesn't move faster or slower because someone is travelling fast. It moves at the same rate is is observed at. If I travel the speed of light the world doesn't speed up to sit 400 years in the future when I return, it travels the same time I travelled at. I travel at the speed of light for an hour when I come back only an hour on earth would have passed, surely.

[@richardfurness7556]

@@fugazinemesis There is no universal time. Your time and my time differ, if only by a minuscule amount, for the simple reason that we're probably located at different latitudes (I'm at 55 deg N) so we're travelling with the Earth at different speeds, the nearer the Equator the faster. For the same reason you'd age that little bit more slowly if you lived at a higher altitude. This has been demonstrated by taking atomic clocks on long plane flights and comparing their timekeeping with synchronised clocks on the ground. They run more slowly in the air because they're travelling faster. Space and time are not separate entities. They form a 4-dimensional continuum called spacetime. There is only one speed - that of light - through this continuum, though of course it's possible to travel through the space component at different speeds. But if you do that, you lose speed through time. Brian Greene explains it superbly in his book Fabric Of The Cosmos - he likens it to driving north-east across salt flats; the more you turn the car to the east, the less distance you'll travel north, and vice versa. If I'm at rest all my speed is through time at the rate of 1 second per second. For a photon all its speed is through space and time stops (for the photon, not the rest of us). There are some excellent videos on KZbin that explain this far more effectively than I could hope to. Try putting 'time dilation' in the search box. Enjoy the rest of your day.

[@nikhil777x]

Heelllooo!😅. Chuck 08:08😂 . .that what is shown in DARK Series' in a beautiful way....✨

[@Fister_of_Muppets]

Far better than "Mike Tyson's guide to Thyme Twavel."

[@dog_backwards]

The grandfather paradox is what happened in the time travel episode of the twilight zone. But what happened is that the guy went back in time and tried to stop abraham lincoln from being assassinated. In doing so he didn't stop the assassination but by attempting to stop it he made himself cease to exist in modern time and his place was taken by his grandson.

[@YueYukii]

In the anime/novel series Stein Gate they build a microwave that can send messages to the past. By doing so with msgs small enough they think they can make minor changes but then realises sometimes can do huge changes like changing an entire city. Ulyimately they face the inevitability of the timeline problem when a catastrophe keeps happening no matter what they do.

[@TheBillykurtz]

A solution to why we haven't seen any time travelers yet is because you can only go back in time far enough to when the first time travel device was invented. So you would need a functional portal/wormhole at your current time and the time you wish to travel to.

[@Explainitarium]

NdGT, I love you. You inspired me to do a Physics AMA today. Got a few dozen takers!

[@DariusOutdoors]

I see what you did there going back in time during this video! It clicked the moment you talked about Looper coming out haha.

[@MisterTee2010]

Even though I am sad that I lost so many family and friends, including my son. If i could go back in time I would not change anything. I would not know what I know now.

[@dashalpha]

"Beyond the Infinite Two Minutes" was a fun and short watch: "A cafe owner discovers that the TV in his cafe suddenly shows images from the future, but only two minutes into the future."

[@jennifercall9014]

What is the temperature in the space between time 1 (enter) and time B (Exit)?

[@theElrin]

9:13 this is a point of Time Travel used in DOCTOR WHO. A “fixed point” in time. It is immutable. It’s a point that must and will happen no matter what and cannot be changed.

[@krissyhimes9357]

Stargate SG1 had the BEST visual effects on wormhole travel!!

[@terrycook2733]

I refer wormhole travel relative to in your house walking through a doorway. You see your destination on the other side or vice versa.

[@missh1774]

1:58 i would think there would be a few more things that would need to line up for a wormhole in time appear.

[@robr177]

The absolute best time travel story by any basis, theoretical or otherwise, is the book The Proteus Operation, by James P Hogan. That is the most likely scenario, based on all theory so far, and based on the fact that paradoxes can't occur, and the fact that nobody has ever come back to our time (and with all that is going on the last few years, there would definitely be people coming here if only to observer history).

[@Deltakitty32780]

Observing time travel, if it were possible, would likely depend on the method of time travel and the theories governing it. However, some hypothetical observations might include: 1. **Temporal Displacement**: You might witness an object or person disappearing or appearing suddenly at another point in time. 2. **Time Dilation Effects**: If you were observing from a distance, you might notice time moving differently for the time traveler compared to the rest of the environment. This could manifest as a slowing down or speeding up of time relative to your own perspective. 3. **Paradoxes**: Depending on the theories of time travel, you might observe paradoxical events, such as a person meeting their past self or altering events that should not be alterable. 4. **Disruptions in Causality**: Time travel might cause disruptions in the normal flow of cause and effect, leading to unpredictable events or changes in the timeline. 5. **Temporal Anomalies**: Strange phenomena or anomalies might accompany the act of time travel, such as distortions in space-time or unusual energy emissions. However, it's important to note that time travel remains purely theoretical and speculative at this point, and we have no empirical evidence or observations of its occurrence.

[@sacfoojesta5197]

Challenge for Neil!!! Can you disprove that what we define and measure as “time” is really just how the human mind perceives the ever-accelerating collective expansion of the entire universe? Would this help explain why things like gravity can alter time, and why things like black holes can pierce through it and/or collapse it? Would that make it a 4th dimension we are “stuck” in compared to the 3 dimensions we can navigate through?

[@bobby49ist]

I thought of.always going back to the year 1859 to 1860 to see where my great great grandfather and my grandmother lived just before start of civil war and see how they managed to live what they ate etc thats still my goal to do this

[@izzycrybaby1164]

Well considering we're speaking theoretically from a point where this is not possible, most likely when we do gain that capability that will unlock whole new branches of physics, perhaps some new constant that isn't light.

[@penamarth]

It would be interesting to hear discussion of Detonator movie. It asks important questions about practical time travel.

[@richardkammerer2814]

I like that water slide analogy, because I get wet before I hit the pool.

[@tutubeos]

The fact that time is relative, means to me that there is not one single timeline where everybody exists. Therefore every single human or object has its own timeline, and you can travel only on your personal timeline. It means that a time machine would make you younger or older, and not let you travel through everyone’s timeline. I think that the movie Tenet got it right, at least more than movies like Back to the future where they travel through one timeline (and creating alternative timelines).

[@isaackitone]

Hey!!! I know Fraser Cain of "The Universe Today"! Collin Jost. Did you know that one great science communicator once asked another great science communicator a question about time travel on your podcast?

[@marshalt0201]

I've had wormholes described as like if you take our plain of reality and fold it over and poke a hole in it

[@sebastianramos637]

8:34 the movie Neil talks is called Back to the Future

[@noelc9961]

Time travelling through a wormhole was also visited in stargate sg1 and also atlantis

[@reeze1895]

Can we please have an episode with a discussion about the TV show "Foundation" on Apple TV PRETTY PRETTY PRETTY PLEASEEEEEEEE 😭 I want to see Neil talk about Harry Seldon for an hour or more STRAIGHT 🙌

[@willrose5424]

Why hasn't he filmed at CERN yet? Or did I miss it?

[@thomasg627]

There's nothing paradox in time travel to the past, we just haven't figured out yet how to do it. If you would travel back to the past you may arrive in the same past you have lived through, but from the moment of your arrival increasingly differs from the timeline you came from, you're simply creating an alternative/parallel reality. From the first moment on the obvious difference will be, you are in a place you were not in the original version and everything you do will add to the differences. If you prevent your parents from meeting there may not be another version of you in this timeline, but there's no paradox, because you haven't prevented your own existence, but just the existence of a parallel version of yourself. If you then jump back to the time you originally came from, you may find the correct time, but you will find an entirely different world and there's still no paradox, because you're still not the person who didn't get born, but another person who was born in a different/parallel reality. There's a load of further consequences from this, i.e. you cannot prevent anything bad that happened in the past, you can only create an additional, parallel reality in which that bad thing doesn't happen.

[@jasonmiskiewicz]

Regarding the grandfather paradox, just remember that time is elastic, not rigid. So even if paradoxes occur, events will restructure themselves to yield familiar events. Source: Harvey (Scorpius clone), Farscape (…Different Destinations, Unrealized Reality)

[@okiph]

first i think i solved the problem with the grandfather paradox... if you go back in time you put yourself in a picture of the position of matter or inside the combination of matter at specific time-point... but the original time-point didn't had you inside of it so linearly you creating new flow of time with you inside of it and it means that you keep go forward in time with previous time-point combination of matter and you inside it... if you really were to went back in time it's like rewinding the movie backward it will repeat exactly as before and create an endless time-loop... so that if you really went back in time nobody will know it because nothing is changing and if you are go back with the future information to the past you just creating new future with previous time-point of matter combination... you move forward in time you just dial back the hands of the clock... and second point is that not 100% sure but probably black holes are 3D and wormholes are 2D it's like the same space have one end in Earth and the other end in Mars without threads connecting them they are probably require very large amounts of energy to stay open and at their center is probably a singularity point... the energy can be pushing like radiation but probably pulling like gravity and very large energy concentrated at converging point is likely to destroy information if wormholes exists it will probably would be one dimension and at small scale like sub quantum...

[@charleshetrick3152]

The show Stargate SG1 actually covered this much better.

The idea of major events still happening despite of changes in the past was briefly touched in a book that I like (issued like 25 years ago). Main character traveled (unintentionally) to the past, killed 3000 soldiers (intentionally) and traveled back to the point when disappeared from original timeline. Then this character searched for information and this was the point when it started to be interesting. Author is playing with the idea, that major events happened similarly as on "prime line" couple of years in difference, slightly different names causing those events. Even ancestors of the main character changed, but he still remembers original timeline. For a light reading book(s) there were some interesting ideas to think about.

[@SundbyCPH]

We "time travel" all the time with e.g. JWST. Looking at galaxies and how they looked millions of years ago...

[@mattjw16]

What is the name of the movie referenced at 7:16?

[@hopefulaardvark]

I actually have a small layman’s theory about how to travel backwards in time. It is not something we could actually apply especially with today’s technology and even if we had the technology to do this, it would be extraordinarily dangerous. It is based on something called a light cone. You cannot change or leave your light cone. However, if a being, or even an object, were to approach the event horizon of a black hole, their light cone shifts towards the black hole and curves backwards causing time dilation. Now, if you think about an engine in a vehicle causing multiple small explosions to generate energy in order to propel the vehicle forward, and you apply that to small black holes instead, you could then curve your light cone so much that you would then travel back in time. Of course, I’ve never done the theoretical calculations for this nor could I. However I think this theory still could hold merit in some way and possibly give us an idea of how to time travel without wormholes. This could seem completely ridiculous to someone more educated than I am on theoretical physics, but I still wanted to throw it out there.

[@say2dithan537]

Chuck is back Tyson is on ...so physics and fun on the go😅😅😅

[@MarinCipollina]

I'd like to go back to near my time of birth, inhabiting my younger body, knowing what I know now. I'd like to revisit historical events that I actually lived through, but would like to pay closer attention them in real time. Could we influence events that have already happened or known to be true? For instance, could you prevent assassinations of world leaders? Save the lives of musical prodigies that died too soon? Fascinating stuff to consider.

[@nHans]

24:25 Dr. Tyson: "If you go to a higher dimension, it's not unrealistic to think that you step out of the time dimension. And now, you look at time as we look at space." Dr. Tyson, meet Doctor Manhattan.

[@seant4884]

Watching this reminded me of The Guardian of Forever

[@mikotagayuna8494]

According to Feynman, reality is the basically the average of all possible outcomes. If you go back and time to change something, you will likely end up not changing anything meaningful as you have altered just one out of countless events leading up to the present and not making a dent on the average at all.

[@TheStrykerProject]

I've always thought, that if the law of conservation of energy holds throughout time, then any object going back into the past would 'dissolve' back into the energy forms it was *at* *that* *time* - for example, a ball of granite travels back in time far enough, it just becomes the part of the mountain it was before it was chiseld out. If a person travels back to when they were still a person, their current make up would disperse, too (back into plant matter, animal proteins, and even whatever particles are consitant within the person between the time lines). Therefore, no, you cannot go back and interfere with events within a given timeline. Going into the future establishes a timeline where the particle make up of the thing/person appear, as-is, and those particles had no effect on the timeline inbetween. And yes, that implies you cannot go forward in time and meet any direct discendent of yourself, since there wouldn't be any. If you were to then travel back in time to a point *after* your initial jump into the future, you would dissolve into those particles as they were, traveling forward through the timeline. So, assuming the law of conservation of energy applies throughout a timeline, then there are no paradoxes.

[@_klee7469]

7:48 the movie Neil referencing is About Time

[@pradeepmalar327]

I think Interstellar has tackled these paradoxes well. It has already happened in your past. It took me a while to realise, but I think it explains some things.

[@REDPUMPERNICKEL]

One cannot travel through a concept except in one's imagination. Time is a concept derived from thoughts of moving objects and time ought not to be wasted with talk of travel through it.

[@Maulfurion]

Center of black hole time stops, when that happens it becomes infinite light and nothing ‘exists’. Size of black hole determine how much of infinity it can handle, eg. an opposite white hole infinity, where time resumes from infinite ‘non-existence’ resuming into time where the speed of light can ramp up and continue existing - create a photon in mid air, what it will do kinda white hole. When these two infinities meet they cause a big bang impregnation. Both you can’t see as even “white” hole the light is confused and primodial before time so you can view like aero gel.

[@huldu]

Time travelling is such a fascinating topic. I do wonder if mankind ever figures something out if at that point we'd attract the attention of some weird aliens that wouldn't appreciate us messing around with any of that. After all we're still human and I don't think, at least in our current form, we'd be responsible enough to handle such a thing.

[@Just1morehour]

As we move at a faster speed or approach the speed of light we slow time done…theoretically until time goes backwards….but no one said that we could slow our speed down anymore than it already is once we go back in time…giving us the ability to speed time up and move forward in time…therefore we are already existing in time at its slowest rate where we can’t return to the future. Theoretically.

[@marclevine3139]

The Flight of the Navigator(1978) was a fun movie.

[@b.justiceforall9544]

Can you talk about the time travel paradox in the movie "Predestination" as it relates to actual relevance of time travel paradox.

[@7meadohstream]

I like star talk 👏

[@SuperCitizen489]

0:39 doesn't dr.manhattan from the comic watchmen explore that question by saying that you see it like a comic page where you see all panels at same time the future and the past and the present,but that makes me wonder if the present exists even for one moment.what all of you think?🤔 Edit:one other thing about time travelers they either died during time travel, become immortals thus they forgot everything the know about, or simply there is guardian that protect the float of time from getting messed up(99.9% GOD),(0.01% i don't know).

[@luizbarrosrj]

There's something I've never heard anyone talking about regarding time travel. When you send an object back in time, aren't you duplicating those atoms (matter)? If I send a gold bar 1 minute back in time, won't I end up with two bars with the same atoms? In other words, I will be creating matter.

[@TheGrahamFactor]

Whatever direction you're going in time is forward. I drive my car forward to the store. Just because I go from the store back to the house doesn't mean I drive backward to the house.

[@duncanjenner4332]

It was once proposed to me that if it was possible to do so,that you would travel back in time but it ..may not be your dimension...also that if it was your dimension you travel to...the return trip may not be as accurate. Paradox again.

[@Antipants-w2i]

Dude, you should've put JGL in the title of the vid. I almost didn't watch this but I 100% would've if I'd known.