Time Travel possible or not?

[justin credible]

I love the theory of time travel and hold up my hands and admit I do not understand all the research I have read on it until I came across this, I understand most of it (surprised me to).
Do you think in the future time travel is going to be possible? Discuss please.

http://spaceplace.nasa.gov/review/dr-marc-space/time-travel.html

 

[TenEightyOne]

I love the theory of time travel and hold up my hands and admit I do not understand all the research I have read on it until I came across this, I understand most of it (surprised me to).
Do you think in the future time travel is going to be possible? Discuss please.

Don't you mean "in the past"?

We already know that some objects effectively time travel (ie are in two places at once) but we also know that energy can neither be destroyed nor created. Things can time travel, they are unlikely to remain sentient in the process.

 

[Danoff]

@justin credible

I know that guy (and he knows me). He's a bright dude. I was totally going to make the joke that you're traveling through time right now (at 1 hour per hour as he says). Of course everything in that article is correct and well known by most people steeped in physics.

If you think of it this way - we are moving through time at a rate different than any other intelligent species on any other planet in any other solar system. So our species is, compared to them, time traveling. Not only do we move through time as easily as we move through space, physics says that the two are intertwined. Especially when considering the speed of light, movement through space is movement through time.

At the moment it appears that we can go forward in time and age less than the people around us (if we have the right tools such as a very fast spacecraft). Interestingly enough, if you could travel faster than light (which is forbidden) you could look backward when you arrived at your destination and see light from the past. That's about as close as I can get to going back in time, and breaks physics still to do it - maybe with a wormhole you could get to a point in space before the light from where you left arrived there (having traveled a longer path).

 

[PeterJB]

Time travel as depicted in movies like Back to the Future would only be possible if the multiverse theory held to be true. As that is time travel from the perspective and reference point of only one person, they would need to be able to transcend parallel universes in order to reach different points in time. Time travel within a single universe would cause a hell of a lot of problems, especially in travelling back in time. For example, if tomorrow I invented a time machine and decided to travel back to say 1990 (two years before I was born, and when my two sisters were infants) and then came knocking on my parents' doorstep, first of all they would think I was a lunatic and probably call the police if I didn't leave, but also they would have remembered this happening in the present and then realised as I got older that I looked exactly like the guy that knocked on their door 26 years earlier. Me deciding to time travel tomorrow would have been determined before I'd decided it by the encounter with my parents that I couldn't control because I hadn't been born yet, but at the same time that encounter was determined by me making the time machine. I probably haven't explained that very well, the same thing happens in the Harry Potter and the Prisoner of Azkaban. From within the confines of a single universe (and a single body) it doesn't make any sense and kind of destroys the laws of physics.

 

[justin credible]

Time travel as depicted in movies like Back to the Future would only be possible if the multiverse theory held to be true. As that is time travel from the perspective and reference point of only one person, they would need to be able to transcend parallel universes in order to reach different points in time. Time travel within a single universe would cause a hell of a lot of problems, especially in travelling back in time. For example, if tomorrow I invented a time machine and decided to travel back to say 1990 (two years before I was born, and when my two sisters were infants) and then came knocking on my parents' doorstep, first of all they would think I was a lunatic and probably call the police if I didn't leave, but also they would have remembered this happening in the present and then realised as I got older that I looked exactly like the guy that knocked on their door 26 years earlier. Me deciding to time travel tomorrow would have been determined before I'd decided it by the encounter with my parents that I couldn't control because I hadn't been born yet, but at the same time that encounter was determined by me making the time machine. I probably haven't explained that very well, the same thing happens in the Harry Potter and the Prisoner of Azkaban. From within the confines of a single universe (and a single body) it doesn't make any sense and kind of destroys the laws of physics.

Understand you loud and clear apart from harry potter never watched any of them.

It would be the strange bit. A week before you are born your parents could have the conversation of "remember that 26 year old lad who visited us saying he was our unborn son from the future" when you haven't been born yet.
Makes my brain hurt but I love it. Got to admit I loved the Back to the Future movies and in 1985 (I was 21) I had hard work sleeping trying to get information and understanding it on time travel. I lot of the time I slipped in to how ufo's if real can travel the distances they do (easy when you are in a library reading what ever is available at the time, no internet) and although there was some theory of loopholes and using light beams it seemed to distance itself from time travel and concentrate on fast travel.
I wish I had the brain power to understand Stephen Hawking as a few people have told me listen to his theory on time travel. I have but to be honest I get lost very quickly.

 

[Com Fox]

Multiverse Theory is the only way that Time Travel could ever be possible.

Outside of Multiverse Theory, if Time Travelling was possible, unless we live in a forbidden era to Time Travel too, where are all the time travellers?

 

[TenEightyOne]

Time travel as depicted in movies like Back to the Future would only be possible if the multiverse theory held to be true.

Multiverse Theory is the only way that Time Travel could ever be possible.

Nope and nope.

Objects can already exist in two places at once with zero time required for them to travel to each/either. However, that can only be in the same instance of a "place" (like your upper nostril, for example). Their final vector has to be across the same piece of space/time.

A multiverse is something different; it's different instances of an object in an identical (or slightly changed, or completely different) configuration.

If you travelled to a separate place in the universe you'd need to ensure that you took all your energy with you with all your photons and electrons in the right order so that you "knew" who you were and didn't arrive as an unpowered cabbage. There also has to be a mechanism to replace your identical energy that you left in this version of the multiverse. It can't happen, the equilibrium of energy doesn't allow it, even with entropically.

 

[Dotini]

@justin credible
Would you consider prophecy - for instance Nostradamus - to be a form of time travel?

 

[Liquid]

Pop cultural time travel seems to be far too simplistic. If you went back in time 6 months from where you are right now, you would be in the vacuum of space and die. Pop cultural time travel allows you to not only go back in time but must also allow you cross space.

Whether any of it is actually feasible is left to be seen. Some argue, in answering the "If time travel is possible where are all the time travellers?" paradox, that time travel will be possible in the future but not until the first time machine is built. That time travel cannot ever have existed before a time machine is built, similar to how a telephone is useless without a second telephone to call.

Loose definition: Is time travel possible? Sure. Time is just a variable we measure. Go across the international date line, which is easiest at the Diomede Islands; the IDL crosses the 3 mile gap between the two islands.

 

[Nessy]

@justin credible. If you enjoy stuff that makes your brain hurt, watch the film called 'Primer'.

 

[Famine]

Forwards possibly, backwards probably not.

 

[Imari]

Forwards is possible right now. Energy requirements are large, but it's totally doable and many technologies in use today have to adjust for the effect.

Backwards is largely unknown. There are theoretically possible ways, but they involve areas of physics that are generally not hard and fast so may not be practically possible. There are also a bunch of paradoxes that seem to prohibit this sort of thing, so who knows.

There are however methods by which backwards time travel would be possible, yet we don't see a huge influx of future time travellers. For example, if a mechanism cannot travel back to a time before it was created. Some sort of restriction seems likely, or there would probably be records of major influxes of people around significant historical figures like Jesus or Buddha.

Advanced reading for those curious.

https://en.wikipedia.org/wiki/Closed_timelike_curve

 

[TenEightyOne]

Forwards possibly, backwards probably not.

Part of the problem with the "backwards" thinking, so to speak, is that it's difficult to measure whether or not something you know is (was already) there was always there or if you sent it back there because it wasn't before. Or something.

 

[Famine]

So what is it?

 

[homeforsummer]

So what is it?

I've never seen one before - no one has - but I'm guessing it's a white hole.

 

[Famine]

I've never seen one before - no one has - but I'm guessing it's a white hole.

A white hole?

 

[homeforsummer]

A white hole?

Every action has an equal and opposite reaction. A black hole sucks time and matter out of the Universe; a white hole returns it.

 

[Famine]

Every action has an equal and opposite reaction. A black hole sucks time and matter out of the Universe; a white hole returns it.

So that thing's spewing time back into the universe?

 

[homeforsummer]

So that thing's spewing time back into the universe?

Precisely. That's why we're experiencing these curious time phenomena on GTP.

 

[Famine]

Precisely. That's why we're experiencing these curious time phenomena on GTP.

So what is it?

 

[homeforsummer]

So what is it?

I've never seen one before - no one has - but I'm guessing it's a white hole.

 

[Nessy]

Okay, so here's another thing. Let's imagine we created a time machine, but it's static to a particular coordinate on the earth. It can travel back and forth through time but must remain in the place it was constructed. What would happen if we went back in time, but in the past there's actually a building or solid object, occupying the space that was clear when the machine was first built. Would the time machine merge with the building or solid object?

 

[Famine]

I've never seen one before - no one has - but I'm guessing it's a white hole.

A white hole?

 

[TenEightyOne]

I haven't read either of the posts in this thread but I have to say I just don't know.

 

[homeforsummer]

I haven't read either of the posts in this thread but I have to say I just don't know.

 

[Nessy]

You guys are mashing up my head.

 

[DolHaus]

Due to time dilation going forwards in time is sort of possible, you could orbit the earth incredibly fast for 2yrs and when you landed more than 2yrs would have passed on earth. You can't come back though, time only goes in one direction

 

[Obelisk]

Forwards possibly, backwards probably not.

Actually...If a time machine did exist, it would let you go forwards and backwards - the catch being backwards means "As far back as the first moment of functionality in the machine". That's my take on it, at least. The very first instance of when a time machine is 100% functional would be the earliest point that one could go back to, in my opinion.

 

[polysmut]

Actually...If a time machine did exist, it would let you go forwards and backwards - the catch being backwards means "As far back as the first moment of functionality in the machine". That's my take on it, at least. The very first instance of when a time machine is 100% functional would be the earliest point that one could go back to, in my opinion.

What places that limit on the machine so that there is a defined point in the past which cannot be passed?

 

[Obelisk]

What places that limit on the machine so that there is a defined point in the past which cannot be passed?

Because that is the earliest possible point for time travel to exist, so to say. Any time before that, and the technology basically doesn't exist, even if the machine has partial functionality.