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

How would time travel work? Journey back through some of StarTalk’s favorite time travel moments from the past, covering topics like The Grandfather Paradox, wormholes, and tachyons. Featuring Brian Greene, Joseph Gordon Levitt, Colin Jost, and more!
What would time travel look like to an outside observer? Learn about how time travel through wormholes would work, The Grandfather Paradox, and whether the timeline cares about major events versus minor events. Is time travel to the past even theoretically possible? We break down ways we are already time traveling through time dilation. What would it be like to look at time from a higher dimension?
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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
#StarTalk #neildegrassetyson
Timestamps:
00:00 - What Would Time Travel Look Like to an Observer?
3:36 TIme Travelling Via Wormhole
5:18 - The Grandfather Paradox
12:16 - Time Travel in Looper
17:00 - Causal Loop Paradoxes
19:49 - If There Are No Time Travelers Now, Could There Be in The Future?
22:44 - Time Travel in Interstellar

[@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.

[@KungFuMaster_]

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.

[@kush5582]

I would buy a book of all betting games and come back

[@cooksburg]

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

[@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.

[@user-lt2yt5ii4d]

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.

[@Vicki-Paz]

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

[@abiofficial-ws7pn]

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

[@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

[@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 🤩

[@FulcrumGhost]

LOVE StarTalk! Thank you Neil!

[@BenjySparky]

Neil and Chuck, y'all rock! Peace

[@QuestHuntersGaming]

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

[@MegaDeano1963]

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

[@TorQueMoD]

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

[@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.

[@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.

[@omerdogruyol7984]

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

[@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 ☹

[@user-mv3rn7vo5i]

Great job Malcom Gladwell!

[@Ben-Ken]

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

[@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.

[@GROW_YOUTUBE_VIEWS_m104]

Your video has the power to make me laugh, cry, and reflect all at once. Masterful!

[@keithjohnsonYT]

Great topic!

[@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

[@Explainitarium]

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

[@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

[@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

[@kush5582]

It's his content not urs

[@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.

[@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.

[@zipporahmusee4440]

This is great!

[@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.

[@RenataKleinRK]

What is donut?

[@jimlaz7456]

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

[@simplicitysitruc]

I love your work neil you're so impressive to my empty mind i would love to meld our empty heads to avoid more things that aren't seen some day

[@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

[@6thdayblue59]

I went to Stoke (UK) The M6 Motorway is a wormhole. You end up 20 years in the past. Anyone in the UK will confirm this is FACT. You go to Stoke, and you go back 20 years. You leave Stoke and you come back to reality. There is no space time difference, we age as we enter and leave. Thank goodness we don't leave there with their six fingers ! Love you guys and your content……….. Keep curiosity alive x

[@AdmiringObserverR]

joke or?

[@nzlemming]

Wait - you got to leave Stoke?

[@nikhil777x]

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

[@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.

[@robertwhitephotography]

OMG Chuck I'm crying.

[@MathewSan_]

Great video 👍

[@The-binge_710]

Great Content

[@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

[@argeliamoran6132]

I'm loving this video 😂

[@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? ;)

[@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?

[@penamarth]

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

[@Johnansvisionary]

Great yes

[@racoonchief]

Awesome!

[@7meadohstream]

I like star talk 👏

[@SydMountaineer]

Stargate - my favorite movies & tv series.

[@seant4884]

Watching this reminded me of The Guardian of Forever

[@krissyhimes9357]

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

[@user-wi4rm9ii6b]

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.

[@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

[@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?

[@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.

[@noelc9961]

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

[@blyman4372]

God bless ya Lord Nice!

[@ManaBDew]

Greetings gentlemen 1’st glance midst the studio events. I think Albert Einstein mentioned it may have been 👨‍🏫 Professor Hawking obj: Time We can go back not to the future. I say there’s an astronomical awaited library for the topic. Amazing 🤩 1 too!!! Ty for sharing 😎

[@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

[@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.

[@PetrSrajb]

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.

[@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.

[@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?

[@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).

[@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."

[@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.

[@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?

[@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.

[@oldcrow6990]

Trippy!

[@charleshetrick3152]

The show Stargate SG1 actually covered this much better.

[@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.

[@monkerud2108]

a question then remains as to the equivalence of the two types of worm holes in a more realistic theory, this is fun speculation but essentially any intrinsic experience has a reasonable causal formulation, at least at some levels, there are problems with diverging histories in the case i put forward as well.

[@arikwolf3777]

I like the movie: _Timerider: The Adventure of Lyle Swann_ from 1982 staring Fred Ward. In which the grandfather paradox it turn upside down. And the book: _Thrice Upon a Time_ from 1980 by James P. Hogan. In which the protagonists send information to the past where the timeline disappears and a new timeline replaced 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.

[@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.

[@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?

[@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...

[@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.

[@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.

[@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.

[@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

[@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?

[@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.

[@ACrowNamedPoe]

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

[@evangaudet]

I’d be scared but interested in time traveling forward. It’s so fascinating that it is a possibility, given that our satellites have a time difference compared to earths time proving the fact that time moves slower the faster you’re going. I don’t think you can go faster than the speed of light however since light is unaffected by gravity. In order to go backwards in time you’d need to travel by something unaffected or bypassing gravity. Wormholes need a gravitational field. How could an object that abides by the laws of gravity pass through a wormhole without being torn apart like a black hole.

[@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)

[@jennifercall9014]

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

[@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.

[@richardkammerer2814]

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

[@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.

[@user-dy5ue2tb6u]

Future shines down on present that reflects the past.

[@jrj2820]

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

[@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?

[@rtyuik7]

...but on a more Positive note, i do like thinking about all of the different "versions" of time travel that we DO have (in science-fiction, at least)...whether its the "one-way bubble" like in Terminator, parodied by Time Immigrants in a SouthPark episode, or the "alternate destination-timeline" style used by DragonBall (mainly Z but Super dabbles in it as well), where Trunks comes from a 'ruined future' but manages to at least save the 'on-screen present' from a similar fate...or Futurama-- not only for the often-cited "Fry is his OWN grandfather" paradox 'solution', but also an episode where the Professor's Time Machine speeds forward to the end of the universe, only for it to repeat and Big Bang all over again...

[@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.

[@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.

[@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.

[@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.

[@thetommantom]

How do you feel about no standing on vegas walkways you can be there but for no time

[@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.

[@DIPANKARROY-jw7pc]

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

[@Fister_of_Muppets]

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