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.

[@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.

[@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

[@abiofficial-ws7pn]

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

[@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 🤩

[@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.

[@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 ☹

[@TorQueMoD]

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

[@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.

[@MegaDeano1963]

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

[@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

[@BenjySparky]

Neil and Chuck, y'all rock! Peace

[@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.

[@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

[@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?

[@Ben-Ken]

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

[@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.

[@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.

[@nikhil777x]

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

[@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.

[@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.

[@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? ;)

[@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.

[@QuestHuntersGaming]

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

[@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?

[@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.

[@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.

[@jrj2820]

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

[@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.

[@jennifercall9014]

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

[@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 😊)

[@Brian-d3s]

I wish i could go back in time to save my life. I hung around the wrong crowd when i was younger & due to the severity i dont think ill last very long. But at least ideas like this give me a short sense of hope. Even if it is just a dream /idea.

[@ACrowNamedPoe]

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

[@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

[@Explainitarium]

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

[@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.

[@KhupThomte1]

If a reflective mirror of acute resolution is positioned half a light years away and we use a telescope with hi-resolution lenses pointing to it to peer back at earth, will we not be able to see what was happening on earth 1 year ago? If so, will we be able to maybe verify or correct our past known history using the same technique? Will we not have a time machine of sorts into the past? Startalk fan.

[@FulcrumGhost]

LOVE StarTalk! Thank you Neil!

[@mattjw16]

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

[@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.

[@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.

[@sebastianramos637]

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

[@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

[@camiloarellano6141]

Ok, here's a question: Does time move slower or faster depending on SIZE? For example: Does a fly observe a fly swatter approaching them (to squash them) at a slower speed than the actual speed of the (human) hand that is moving the fly swatter?

[@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

[@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.

[@Dariddda]

Theoritical question. What is you travel at the speed of light for 1 second (I know it's not possible, but that's why it's theoretical) would there be infinite amount of time passed for others? also how does passing the speed of light would suddenly change the passing of time backwards?

[@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).

[@penamarth]

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

[@bdawg2513]

So if I did go back in time to when my parents met, what would stop me from preventing them ever meeting? What would happen to prevent me from doing that? And how would it appear to me, and everyone else observing my attempt?

[@danielspahn2593]

We are all time travelers, we just travel one way

[@_klee7469]

7:48 the movie Neil referencing is About Time

[@b.justiceforall9544]

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

[@madcow3235]

OK so. My question is how dialated would your time be if you were at the base of a space elevator in the Marianas trench to the altitude of the Satellites and had a zoom meeting with the astronauts? So auqanaut to astronaut zoom meeting, how dilated would there time be?

[@MathewSan_]

Great video 👍

[@omerdogruyol7984]

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

[@ignorasmus]

@11:10 - I have heard this little story from Neil earlier (I believe I have watched/ heard every single episode of StarTalk & some more of Niel's talks) and the obvious error in it, always bugs me. You could have sent the message at an even earlier point in time when your buddy was just sitting comfortably somewhere & asked him to watch out for the banana peel at so & so place at so and so time. I don't understand the point of this story - if there is any. May be it was just meant to be a joke that did not tickle me the right way.

[@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.

[@michaelwhalan9783]

If we can collapse the probability wave then can that include just a little backward or forward in time?

[@DIPANKARROY-jw7pc]

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

[@SydMountaineer]

Stargate - my favorite movies & tv series.

[@randomfromrendell1013]

Good day Mr. Neil, are block holes solid? If yes can we melt in and use it as a tool or weapon

[@tim79tim]

Hey Neil, I own your blu ray of cosmos but I would like to buy the 2nd series. Will I be able to buy it in europe in the near future?

[@williamowuor-s8e]

what if someone time travel to the past to stop something from happening like someone tripping over, then changes that then comes back, how would have the person know that he or she prevented a person from tripping if they never did.in short try to apply the grandfather paradox to all possible outcome. what if time travel was not through one time but multiple time possibilities.

[@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.

[@wlockuz4467]

What is the music that plays between the clips????

[@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

[@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.

[@daveking3494]

What is the opposite of going faster than the speed of light? If I sit on my couch and watch television for the next 10 years and don’t move a muscle, that is probably the slowest that I can go, or is there another way?

[@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.

[@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.

[@bartoszjasinski]

I think that wormhole thing can look like this. Wormhole bends space to 'connect' two different places. Yes there can be time difference, but who said that this travel through wormhole is instantly. Maybe for you as the 'traveler' it will be like blink of the eye but it will make you much older in a second or keep you young and handsome for years until you appear on the other side. For you it will be moment but bended time in wormhole will "adjust" you to the final destination. I see some issues with that concept but if wormhole will work only in one direction (you can travel only to 'older' or 'younger' space) is it a bad idea?

[@justthinking5091]

If you put one end of the wormhole close to a black hole, couldn't the gravity of the wormhole not also come through and affect the other side of the wormhole?

[@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.

[@ivanarcheous4731]

Hey Neil. Regarding time traveling to the past, wouldn't the very goal of time traveling be a paradox? Sort of like the Bootstrap paradox For example you prevent two persons from meeting (not necessarily from your family tree). If you're successful, wouldn't your very goal of you time traveling in the first place be nullified, because they never met in the new timeline?

[@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.

[@faridbelaidi8858]

Wormholes are bad idea: what if you open one and find the other side near or in a black hole? What gravitational impact (space loop ?) on the "entrance"'s environment?

[@RuchirRathore]

Dear Dr. NDT, on the subject of wormhole... I'd love to get your take on science of Stargate.. as in Stargate SG-1 and Atlantis series. And on subject of time travel, your take on movie "Predestination" Thank you... Always love your shows.. Just as a side note, I was 9 days old when you met Carl Sagan on Dec 201975

[@Figger01]

Does math HAVE to explain all cosmic phenomena, and if so, is there still some math we do not understand and could that math be different in worm and black holes?

[@robo5013]

Math is a language that we invented. The only rules it has are the ones that we've assigned to it.

[@Figger01]

So with any human created technique or technology there could be flaws. Example; I have always believed that computers could be our downfall or, hopefully, our greatest achievement to progress forward, if used in a positive manner.@@robo5013

[@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.

[@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.

[@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.

[@jeremymoss5537]

instead of the traditional heater air conditioner create a wormhole between northern southern hemisphere when it is too hot in your house transfer the hot air out and the cooler air in. or put an air conditioner inside a worm hole the cool air is facing you and the heat that is in your room faced some other place that needs to be warmed up

[@a-totally-random-person]

Do we know how long it takes for stars to "form?" What are the stages? Do we know of stars that are younger than human civilization?

[@AzeAlter]

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

[@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?

[@DeuxRouesUneTente]

They actually used this in Stargate SG1... Something about a solar flare happening just at the "right" (or well, wrong...) time while the wormhole is being established. Episode "1969" from season 2.

[@janerkenbrack3373]

How do people who believe in time travel account for the Earth (as well as our solar system, galaxy, etc) are moving? If you went back or forward in time, wouldn't just find your self in empty space?

[@PatMaddox]

You don’t skate to where the puck is, you skate to where it’s going to be.

[@janerkenbrack3373]

@@PatMaddox Some people get hit in the head with the puck, I guess.

[@davidknight5331]

Isn't it true that everything I am made of is already in the past in one form or another? Doesn't that mean that if I were to go back to any point in time, my constituent parts would be in two places at once? Is that even possible? I feel like my possibility wave is already collapsed.

[@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).

[@noelc9961]

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

[@sqlb3rn]

Time travel only exists in theory like the square root of negative one. In reality as far as the universe is concerned every moment is and always will be the current moment of now. The flow of time is only a concept of a conscious mind, similar to how music is an interpretation of sound pressure changes by a conscious mind. That's my opinion and I'm sticking to it.

[@cookieDaXapper]

.....if object A moves fast enough to reverse space-time surrounding itself, what happens to its forward travel? ...does it fold back upon itself or self annihilate?....does its speed begin to decrease because of its now reverse time-space travel? Great for science fiction extrapolation, not so much in practicality.

[@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

[@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...

[@enriquegomez5337]

So the faster you move the slowest the time flows, and that’s a way to go to the future, the clock of a photon is stopped because of the speed it has, so at the time it arrives to my eye is like it’s arriving to the future but at that very moment everything I’ve done is in the past, doesn’t it mean we are living in a superdeterministic universe?

[@neb-taui-djeser1060]

What about the energy, the matter you are made off that once belonged to something else before you came to existence?

[@janewayofchaos3255]

I'm wonder what would happen if one was on a ship going the speed of light, then turned on a light and shines it out the window in the direction your going?