Thread: time travel

Hello everyone,i am new to this site,and although im not an academic,i find myself having a growing interest in science,particularly physics,which i have an A-level understanding of.I was wondering if anyone could answer me a question on the subject of time travel-from what ive read and understood-one could in theory travel in time using a black hole-but would it be possible to travel in time without moving significantly in space?
Im sorry if this is a very basic question and some more knowledgeable than myself have to "think down" here,but id be very grateful to anyone who could answer this and if possible outline how it could be achieved.
Many thanks.

Whether time travel is somewhat allowable by our current understanding of physics is less important as to whether it is practically possible.
Your example of using a Black Hole, for example, would be useless considering you could not leave the black hole, much less survive the entry- no matter how much armor you wear.

To travel through time without traveling through space would require time to be a separate physicality from space.
As it stands, considering we're not inundated with tourists from the future, either there is no practical means for time travel even for advanced human civilizations or the human species is wiped out before we reach such advancement. I lean toward the former. We can move through time and space- but we cannot move in any direction we choose through just time.

Thank u for ur reply,very helpful...i'd kind of reasoned that travel to the past would be frought with complication,for example,.if u travelled back in time,then returned to the place u left from,only 2 minutes earlier,would u not see yourself preparing to go into the past??And would that mean that there were now TWO of you??Can of worms is the phrase that springs to mind!!

A friend suggested to me that all ud have to do in theory would be to get close to a really massive object,thus slowing down your time compared to those u left behind...but it wasnt quite satisfying as an answer,because obviously ud still have 2 travel in space to reach the massive object.

So then,there is no theory whichwould allow u to travel forward in time yet not moving in space at all??

Im sorry if this question betrays lack of knowledge,as i say-i've only done science to A-level and scraped a B grade-13 years ago-so im rusty2say the least,and am only now getting the bug again for knowledge....so it would be that as space and time are intertwined,travel in one dimension(time)would automatically include travel in the other(space)?

Again,thanks for your reply....Fascinating subject-i feel that some time in the future,discoveries will be made to enable the theory of travel to the future a reality-what i'd give to be around for that!!
I'm interested to know-What is your opinion on that?

Could it be possible that humanity has evolved sufficiently enough that time travel mystery has been solved,but also,evolved enough to know how to use it sensibly?My uinderstanding (limited though it is),is that travel backwards in time is probably impossible,but more achievable in the forward direction...and as u point out-we aren't inundated with time travellers from our future,unless they are doing it very carefully and covertly...Sadly though,id have 2 say i probably agree that humankind wont even make it anywhere near that level of advancement,we'll probably be too busy putting our minds n resources into wiping each other out.....
Time travel though-its a helluva thing to have stuck in yer craw!!!

Originally Posted by asthmaticdragon

So then,there is no theory which would allow u to travel forward in time yet not moving in space at all??

Well... there's cryogenic freezing- not exactly time travel but that effect is the same...

Originally Posted by asthmaticdragon

so it would be that as space and time are intertwined,travel in one dimension(time)would automatically include travel in the other(space)?

I would say so, yes.
Analogy follows:
Forget thinking of time as a flowing river.
Think of it instead, as fine particles dispersed throughout all of space.
When you drag matter across it, you see an effect. Mass warps spacetime, such that you have the effect of gravity. You also have the effect of passage of time. Since motion is relative, you cannot easily stand still. You are on the Earth and the Earth is moving. The solar system is moving. The galaxy we are in is moving. But if you could leave Earth, the sol system, the galaxy and far beyond... if you could go to a place where you could stand perfectly still and not move... then you might fail to perceive the passage of time. Which would render the action useless since you wouldn't remember it because time did not pass. Also, because whereever that place was, your physical body probably couldn't exist there and you'd go *poof.*

Originally Posted by asthmaticdragon

!I'm interested to know-What is your opinion on that?

I'm not so optimistic about the future. I'd rather go back in time and stalk a dinosaur.

Originally Posted by asthmaticdragon

Could it be possible that humanity has evolved sufficiently enough that time travel mystery has been solved,but also,evolved enough to know how to use it sensibly?

Probably not.
We do very little responsibly.

In the far, far future, is it possible to think humanity developed the ability and the responsibility? It's possible, but still very unlikely.
I think that an advanced humanity will pursue something more interesting than traveling through time... they will travel through vast distances of space.

Thanks for the full and interesting reply...i'll go back and read it again more slowly,for shame,i'm not blessed with a quick mind.What u said about going to a point where you could stay perfectly still,again,'scuse my ignorance here-that would'nt be possible at all,yeah?Like,ruled out completely-beyond speculation?If everything is moving relative to everything else,then nothing can or ever could be seen to be at rest?
I know thats probably a dumb question,but just wanting complete clarity!
(Also-its kind of odd that the intuitive way to think of time is time as a flowing river-it seems like it's the natural way to visualise it)
And cryogenics-i guess that would FEEL like time travel when u were defrosted,but i imagine once i'd settled down into futurity,id feel similar to how i feel when i play scrabble online with scrabblesolver.
I have to say,im also not too optimistic about the future really,maybe there will be some kind of awakening,not wanting to sound like an old hippy-but i think that humanity needs that kick up the arse.When u consider the brain and its 300 billion neurons,one thing u can be optimistic about is human potential i suppose.
And travelling back in time-thats an awesome thought,but seems to be the more problematic direction.
Ur point about space travel,would u say that the reasons for the lack of recent manned space flights is purely down to finicial constraints?
I watched all the stuff abot mars curiosity-man,those scientists and engineers are nothing short of amazing,that was a massive achievement...so u reckon that the next step will be man on mars,and maybe beyond?
That is an exciting thought-that alone cld justify being freezer drawered for-i dont know much about this-have u any idea urself how advanced(or not)the space flight technology is at the moment?

Sorry if my replies get scatter brained at any point-it's just that im fairly new to this kind of thing,and there are way too many thoughts whizzing around in my mind tank at once!#

Also-why did u choose the quote "inter arma enim silent leges"?

Originally Posted by asthmaticdragon

What u said about going to a point where you could stay perfectly still,again,'scuse my ignorance here-that would'nt be possible at all,yeah?Like,ruled out completely-beyond speculation?If everything is moving relative to everything else,then nothing can or ever could be seen to be at rest?

Again, I would say so. If you're going to claim ignorance, stop saying informed things.

Originally Posted by asthmaticdragon

but i think that humanity needs that kick up the arse.

True....

Originally Posted by asthmaticdragon

Ur point about space travel,would u say that the reasons for the lack of recent manned space flights is purely down to financial constraints?

yes, as well as political due to the finances. A lot of voters don't want to spend money on something they may or may not see immediate returns on. They just are simply not informed enough on the full ramifications. So they end up voting in political promises for more immediate reforms and spending- such as welfare.
Now, I'm not saying that general welfare is bad. But there should be a balance. With a greater financial and material availability- it wouldn't be a concern,. The irony of there is that if we get off the ground, we can expand finances and resources.

Originally Posted by asthmaticdragon

so u reckon that the next step will be man on mars,and maybe beyond?

There is a push for Mars. But I think that the lull after Apollo still has not worn off. Humans will probably stay grounded until something galvanizes them into considering the future of space travel, again.
I'm more a fan of exploring the Jovian moons... but I suppose MArs would make a good first step and a presence on Mars brings us closer to the outer moons.

Originally Posted by asthmaticdragon

have u any idea urself how advanced(or not)the space flight technology is at the moment?

Advanced enough to go out there and poke around a bit. Just not really advanced at all. We need to learn by doing and as your O.P. suggests, the only way any of us would see it would be to exist beyond our expiration date and travel to the future.

The day may come, however, when something threatens our existence on Earth. While being able to colonize and travel through space would be a boon at that time, we're no where near that point yet. It would probably need a couple hundred years of actually doing it. I think if a threat did come up, we'd be out of time...

Originally Posted by asthmaticdragon

Also-why did u choose the quote "inter arma enim silent leges"?

I do not believe that a rule is a rule or the law is the law.

Lol-yeah,maybe it's less ignorance and more a confidence issue,i know which one i'd rather be for sure...it has to be said,some people have intelligence that is frankly intimidating,,especially scientifically minded people,and sometimes it makes u aware of just how LITTLE you know yourself.The only person i can find in my real life that i can actually have this kind of conversation is my uncle-and he is one such person-lovely guy-super knowledgable,computer genuis.Sometimes talking to him leaves me feeling like a proper simpleton though!
I suppose in some way-it's ALWAYS about the money,so in a way the cold war was actually a good thing for human advancement,i imagine the NSA budget now is considerably smaller than it was back then?And of course-there should be a balance and there are good arguements on all sides i reckon,the allocation of spending of taxes etc is not a job i'd fancy myself-i guess space missions are hard to justify in these times in the face of rising poverty and what have you-if only there was an easy solution-i can see the irony too-i guess the rule that u have 2 spend money to make money holds true-i'd imagine commercial space flight/space tourism will help things along,i think it will be a necessary evil for the advancement of the race.

Can u remind me please-what is the name of the probe studying jupiter?It's not Cassini-thats Saturn right?
The little i do know about the discoveries there are pretty fascinating-is'nt one of jupiters moons geologically active due to gravitational effects or something like that?
Yep-the moons there are pretty fascinating-but it makes me realise just how YOUNG we are in terms of discovering the universe and exploring it,that we're not even at the end of our solar system!
As u say-at least a few hundred years...lets hope we've not destroyed ourselves b4 then.
I guess the thing to crack is figuring out how to power any ships and get them to speeds that would make travel practical...
It would be amazing if we could somehow manage to glimpse the future...i get the feeling myself that it's gonna be death or glory,too close to call which one!

Originally Posted by asthmaticdragon

some people have intelligence that is frankly intimidating,,especially scientifically minded people,and sometimes it makes u aware of just how LITTLE you know yourself.

I've found that a person that doesn't know much science might know a great deal about something I'm very ignorant about.

Originally Posted by asthmaticdragon

i can see the irony too-i guess the rule that u have 2 spend money to make money holds true-

In this case, it's plausible that we have to spend money for our future to survive.

Originally Posted by asthmaticdragon

Can u remind me please-what is the name of the probe studying jupiter?It's not Cassini-thats Saturn right?

Yes, Cassini did a fly by of Jupiter on its way to Saturn for the Cassini- Huygens mission.
New Horizons also did a fly by mission as it passed Jupiter on its way outward and currently, Juna is on its way to Jupiter. Juna was preceded by Galileo on Jupiter missions.
There's another I heard of proposed for Europa... Not off the ground, yet. I don't remember the name; I'll have to look it up.

Originally Posted by asthmaticdragon

is'nt one of jupiters moons geologically active due to gravitational effects or something like that?

Are you thinking of Io? Several Moons are because of the gravitational kneading they experience.

Originally Posted by asthmaticdragon

I guess the thing to crack is figuring out how to power any ships and get them to speeds that would make travel practical...

Giant space hamsters. In run-wheels. Easy to fuel, replace and friendly, to boot. Although, you know the Klingons will laugh at us.

Sacrifices must be made.

Hi,thanks for the info there...i hear what you're saying,personally,i find i can understand basic principles and concepts when it comes to general science,but with regards to the technical side of things,i'll only get it through hard work and tenacity,unfortunately,it feels like im just not wired for mathematics-it's the only thing i've really struggled with in my education...i can however,get a tune out of most musical instruments,and pick up a melody or chord sequence by ear!And thats pretty cool-but it's not much use for trying to figure out the universe we live in-just makes the soundtrack to it shit hot!
I think that Io was the moon i had in mind,it was featured in something i saw on t.v.
Giant space Hamsters...what a brilliantly insane picture that is!!!
I'd imagine though that with the universe so rich in colossal amounts of energy,there are brilliant minds right now trying to figure out how to tap into it,whats needed now is a Faraday for the modern age.
Do u mind me asking what it is you do for a living?
Hope u are well.

I struggle with mathematics and am useless with musical instruments. You're one up, there.
If you're thinking about the future, wondering what's to come, I'd actually recommend against thinking too much on time travel. See, there's something about knowing the outcome of something... it detracts from the journey. Humans do have an exploratory nature.
We don't just want to solve a mystery- we want to go through the motions of finding the clues and piecing it all together.
Knowing the conclusion kinda spoils the adventure.

Maybe a GRB will wipe out humanity sometime in the future- maybe four thousand years from now.
Maybe it won't- maybe we will head out as an interstellar species, building a vast civilization across the galaxy.
Whatever is to come- we simply do not know and therefor, we can only diversify our efforts. Prepare for anything. But if we could see the future, we could eliminate the guesswork. We could know our direction and sometimes... going in many directions is just plain better.

Hypothetically... if somehow I had the chance to travel in time, I wouldn't go to the future. I can dream, imagine, speculate and maybe even predict what might be in the future. And that action may just be a small part of contributing to make a future.
But the past... to see what was and let it be... that is something I might take up. To observe the origin of life on Earth or look at Mars or Venus as it was a billion years ago.
To see the living things that once existed but no longer do.
To witness history. I can see that as a temptation. Not the future. The future is for making. Not just observing.

You make a lot of good points here.I'm taking a little time to think them over-which kind of illustates the point i think you are making-if i had a working time machine-i'd arrive at my conclusions almost instantly,without having gone through any meaningful contemplation.I dont really think about the future that much,i have too much to consider in each moment,but it is a kind of irresistable thing to think about-so many implications!
Knowing the conclusion spoiling the adventure,also,would knowing the conclusion affect the outcome of the conclusion itself-and would knowing the conclusion lead to a different kind of path altogether??!!
Aaaargh-it's a minefield.
Maybe i'll think about Quantum theory instead...hang on,maybe not.
Can u reccomend an area of science that wont blow the mind?
I expect not-and thats why it's an amazing thing.
Anyhoo-im going to take some time to chew all these things that i've heard over n over again,like a cow would with grass.
Thanks again for all your replies,and everyone else who has contributed.

Also-if we could observe Mars billions of years ago-is it possible that we might see versions of ourselves?
Just a thought.
I suppose the thing about time travel maybe arises because we know deep down that we cant experience anywhere near a long existence on a par with geological time-if we could,maybe that would be more satisfying.Or mind numbingly boring.I cant help thinking about how huge an insight it was when people including Einstien realized that time was relative and dependent on ther motion of the observer-it's such a huge thing.
In your opinion,has there been an intellectual insight on a par with this since then?
If u can kindly suggest any-it may help get my mind away from the subject of time!

Originally Posted by asthmaticdragon

In your opinion,has there been an intellectual insight on a par with this since then?

String. But it is not tested, not even testable, at this time. And it's a work in progress, as yet not complete. Daunting, yet elegant in many ways... and fugly.
I think Einstein would dislike it as much as I do. And admire it, as well.

To travel forwards in time travel at a speed very close to the speed of light for a certain distance then return to the source, others will have aged and you will have not.
To travel backwards in time enter a black hole that is rotating sufficiently fast enough that when you are in the space time the black hole is rotating and travel at a fast enough velocity (depending on the speed of the rotation of the black hole) you will appear to be traveling to an outside observer faster than light so that they will actually see you leave before you enter the black hole.

Methodologyfor doing either of these presently is non-existent, to say the least the backwards time travel theory has no proof and does work in theory, but as said is yet to be proven.
People may have their own theories for time travel and it may indeed be very easy to do but we just don't know yet, if ever will.

Hope this helped!

Originally Posted by Quantime

To travel backwards in time enter a black hole that is rotating sufficiently fast enough that when you are in the space time the black hole is rotating and travel at a fast enough velocity (depending on the speed of the rotation of the black hole) you will appear to be traveling to an outside observer faster than light so that they will actually see you leave before you enter the black hole.

Ok now you have me curious about this, how would you be able to do this without breeching causality, and if you did violate causality wouldn't this then create a time loop in which you would then be stuck?

Originally Posted by Ascended

Originally Posted by Quantime

To travel backwards in time enter a black hole that is rotating sufficiently fast enough that when you are in the space time the black hole is rotating and travel at a fast enough velocity (depending on the speed of the rotation of the black hole) you will appear to be traveling to an outside observer faster than light so that they will actually see you leave before you enter the black hole.

Ok now you have me curious about this, how would you be able to do this without breaching causality, and if you did violate causality wouldn't this then create a time loop in which you would then be stuck?

Well this is where we have a problem in our understanding! This is always when the grandfather paradox crops up!

The premise is that when you travel backwards in time and go forwards again you are in a new 'timeline', this is known as the Everett's many worlds interpretation. Well specifically that is known for an explanation into Quantum Mechanics and superposition, wave functions etc but it applies here to as it does imply that Schrodinger's cat so to speak can be observed to live rather than die; traveling back in time does not mean that the laws of Quantum Mechanics suddenly always remain the same no matter what, they are still part of a system of probabilities so we would expect to observe no time loops, no grandfather paradoxes as the systems behave according to probability still.

It really does make sense if you think about it, imagine all the Quantum Fluctuations in your body, particles moving about into different places it would be strange to assume they will all go where they were before because that would imply you know where they are going to be AND their momentum, which again violates the uncertainty principle, which states you cannot always know the position and momentum of a particle, only more of the one and less of the other. So it would be logical to assume that by traveling back in time and going forwards you would not be violating causality, as causality as we measure it on a macro scale of seconds, weeks and years is happening trillions and trillions of times over on the micro/quantum scale so killing your grandfather won't terminate your existence, or mean you get trapped in any time loop.