Time Travel...Impossible?

There are other ways of time traveling(ex. travel faster than light speed to watch past)

Therefore, time travel is highly possible :)

Why would we end up in the middle of space? I guess your logic is that there is some center of the universe somewhere, and that the earth is moving around relative to the center of the universe, and that when we time travel, we stay in a fixed position relative to that center, thus leaving us at a spot where the earth has moved away from.

The problem with that logic is that there is no "center of the universe" point. There's no way to "stay still" in space, the only thing you can do is define your position relative to other objects.

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Original post by ruler There are other ways of time traveling(ex. travel faster than light speed to watch past) Therefore, time travel is highly possible :)

then the only problem is how to get faster than light speed to start moving backwards thru time? then how do u get back on our side(slower) of the light-speed barrier to be able to experience the benefits of the time-travel?

this time machine should also apply some space translation because if you travel thru the time, u have to consider the position of the earth relative to the day u're going to..

maybe the better solution is to place this "time machine" in the space, in a point where is sure that can't be planets or so -__-

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Original post by knowledge Quote: Original post by ruler There are other ways of time traveling(ex. travel faster than light speed to watch past) Therefore, time travel is highly possible :) then the only problem is how to get faster than light speed to start moving backwards thru time? then how do u get back on our side(slower) of the light-speed barrier to be able to experience the benefits of the time-travel?

You don't actually travel back in time. The point is to travel faster than the light sent off/reflected off Earth. You don't even have to travel faster than light if you can take a shorter route (wormhole, hyperspace etc). If you could instantly move 10 lightyears from Earth, you could sit back and watch events that happened in 1994.

You'd just need a really really big telescope to catch all the light that spread out and probably a clear shot so that nothing was in the way. :)

I could share a revelation I had 1-2 or so years ago. We all know that when looking at a star, we're actually lokking at its current state from 3 million or so years ago. And that this star doesn't really exist, that the light of the whole process hasn't reached us yet so that we can see that it's currently only a small pocket of gas from a super nova.

This is nothing new, however, if we would -instead- place ourselves in a spaceship and accelerate towards that star and keep it focused on our main viewing screens - we'd see the whole process speed up. We would be getting closer to the star and thus closer to its current state since we're also receiving newer and newer light it's transmitting.

The result of all this would be that the closer we get to the star and the faster we travel towards it the faster we'll be seing the star's life cycle take place - like a movie going in a accelerated "fast forward" mode. =)

I had this revelation while looking at the stars during winter here in Sweden. =) Imagine that!

-Johnny Sjöberg

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Original post by daviiie Just imagine if you had a device that would send you back through time to your exact position only 25 years ago. The only problem is that our current position isn't fixed, so we would probably appear in the middle of space, or worse, in the centre of the earth or something.

If we had that device, wouldn't it be a pretty safe bet that it could allso compensate for stellar drift.

One of the revelations i had(while sitting infront of the computer) is that the twin paradox can't be true(the one with the twins and the spaceship and one twin travels faster than light then comes back only to find that the other twin is now 50 years older than him).

However, since speed is relative(witch makes travel at the speed of light pretty easy if you use a single photon as a point of reference) the only thing that remains witch can influence time when you travel at great speeds is distance(that's kinda why they call it the space/time continium and not velocity/time continium).
Therefore it's fairly safe to asume that if you travel faster than the speed of light and thus traveling back in time you would then on your way back travel forward in time just to arrive around the time you left(+ the time it took to travel).

Witch leads us to the double twin paradox.
Lets say you got two pairs of twins, born on two different planets lightyears apart on the same day(rellatively speaking).
One day one twin of each pair travel to the other planet, using pretty fast space ships.
On the mid point the two space traveling twins meet and finds that they are exactly the same age.
Uppon arrival(on the other planet) they meet up with the other twin and finds that they are alot older than themselfs.
Later on the way home they meet up again, and behold, they are the same age, and the same again with the twin that they left home.

Temperal mechanics gives me a headache, figuring out the exact causes(hint: there are two of them) of z fighting and the definite solutions(hint: there are tree of them) for them was easier.

If you were travelling through space in a car at the speed of light... & turned your headlights on, what would happen? lol

(don't answer, its a joke question, I know the answer)

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Original post by the_recon I could share a revelation I had 1-2 or so years ago. We all know that when looking at a star, we're actually lokking at its current state from 3 million or so years ago. And that this star doesn't really exist, that the light of the whole process hasn't reached us yet so that we can see that it's currently only a small pocket of gas from a super nova. This is nothing new, however, if we would -instead- place ourselves in a spaceship and accelerate towards that star and keep it focused on our main viewing screens - we'd see the whole process speed up. We would be getting closer to the star and thus closer to its current state since we're also receiving newer and newer light it's transmitting. The result of all this would be that the closer we get to the star and the faster we travel towards it the faster we'll be seing the star's life cycle take place - like a movie going in a accelerated "fast forward" mode. =) I had this revelation while looking at the stars during winter here in Sweden. =) Imagine that! -Johnny Sjöberg

its like doppler effect...
but with the light

about the doppler effect:

actually... it depends on your perspective...

If you are somebody on earth, watching the car drive by, you will see something entirely different than the guy actually in the car.

A bit OT: Why isn't this in lounge?

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Original post by ruler There are other ways of time traveling(ex. travel faster than light speed to watch past) Therefore, time travel is highly possible :)

According to the theory of relativity in order to travel faster than light you'd need infinite energy because the faster you move, the more mass you gain, approaching infinite mass as you reach the speed of light. Therefore it is impossible to move faster than the speed of light as it would require infinite energy. The only possibility to get to a location faster than light would be to take a shortcut through spacetime; never exceding the speed of light, but getting to the end location in another manner.

That's how Star Trek solves the problem, right? With the whole subspace warp bubble thing, you're moving through space that's not quite real space... and obeying the rules of physics in that "sub space" but from the perspective of real space you're travelling several times faster than light.

I believe the current understanding of physics say that, if you can teleport in time, you can also teleport in space, so that's not really a problem.

Unfortunately, we know of no technology or physical phenomenon that lets anything bigger than a quantum particle teleport, even in space, much less in time. I think that's a better reason why time travel isn't possible :-)

Are we not time travelling everyday?

I hope you guys know this already but here it is,

If you take two of the most digitally precise clocks we can make (syncranise them) and put one in a space shuttle and the other in a car then fly the spaceship through space and drive the car on the ground to the other side of the world, the two clocks will no longer be in sync with on another.

How is time travel possible when time is just a imaginary reference we use to keep track of events. And how could you do something so complex around something so fragile that it can be changed by the normal speeds of travel

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Original post by JMOmandown I hope you guys know this already but here it is, If you take two of the most digitally precise clocks we can make (syncranise them) and put one in a space shuttle and the other in a car then fly the spaceship through space and drive the car on the ground to the other side of the world, the two clocks will no longer be in sync with on another.

Yeah, that's a test of the theory of relativity. Time is relative just like space. Depending on your speed, time can move faster or slower relative to you. However, you have to be going very fast for quite a while for it to amount up to anything.

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Original post by JMOmandown How is time travel possible when time is just a imaginary reference we use to keep track of events.

Time is no more imaginary than space is. I do not see the point you are trying to make.

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Original post by Polymorphic OOP Quote: Original post by ruler There are other ways of time traveling(ex. travel faster than light speed to watch past) Therefore, time travel is highly possible :) According to the theory of relativity in order to travel faster than light you'd need infinite energy because the faster you move, the more mass you gain, approaching infinite mass as you reach the speed of light. Therefore it is impossible to move faster than the speed of light as it would require infinite energy. The only possibility to get to a location faster than light would be to take a shortcut through spacetime; never exceding the speed of light, but getting to the end location in another manner.

Actually, that's not 100% correct.
I think it wouldn't be too hard to accelerate to 99.99...9 % of light speed, but it's impossible to cross it.
The reason for this is that time slows down for the spaceship, so it would take an infinite amount of time to reach light speed. If the space ship keeps accelerating at 1 g (9.8m/s²) it would take 354 days to reach lightspeed as observed by people on board the ship. The energy required to accelerate from 0 m/s to 1 m/s is the same as the energy required to accelerate from 299000000 m/s to 299000001 m/s (at least as observed by people on board the space ship). The problem is that for a "relatively" stationary observer the space ship would take infinitely long time to accelerate to that speed, and if he lived that long, would seem to accelerate less and less. The mass doesn't approach infinity as the space ship approaches the speed of light, the inertia however (resistance to change in velocity) approaches infinity (seen from an outside observer).

Anyway, the assumption that "because the mass approaches infinity as the velocity approaches the speed of light, it's impossible to reach the speed of light" is false, because the energy stored on the ship (fuel) would also approach infinity (at exactly the same rate as the mass).

I think it is impossible to travel faster than light.
I think it is possible to get to another place faster than light(wormholes, teleportation, warp, subspace, hyperspace you name it).