Would Time Travel Really Be Space Travel?

[aguy2]

Why do all the speculations concerning the possibility of 'time travel' presume a non-dynamic staring point, when there is no such thing?

 

Any point on Terra is moving. It is rotating in relation to the planet's axis. It is orbiting our sun. Our sun is orbiting the center of the Milky Way, the Milky Way is moving closer to Andromena, and our glactic cluster as a whole is moving toward a point behind the Virgo Cluster. The total sum of these velocities might be something like 1/35 C.

 

Wouldn't it stand to reason that if you were to travel 35 seconds into the past, you would reappear into empty space approx. 186,000 miles ahead of where you were, and if you stayed in place, 35 seconds latter you would be right back to when and where you were?

aguy2

[padren]

Why do all the speculations concerning the possibility of 'time travel' presume a non-dynamic staring point, when there is no such thing?

 

Any point on Terra is moving. It is rotating in relation to the planet's axis. It is orbiting our sun. Our sun is orbiting the center of the Milky Way, the Milky Way is moving closer to Andromena, and our glactic cluster as a whole is moving toward a point behind the Virgo Cluster. The total sum of these velocities might be something like 1/35 C.

 

Wouldn't it stand to reason that if you were to travel 35 seconds into the past, you would reappear into empty space approx. 186,000 miles ahead of where you were, and if you stayed in place, 35 seconds latter you would be right back to when and where you were?

aguy2

 

By speculations about time travel, do you mean science fiction stories that would have been really really short if the protagonist had used a time machine and popped up in deep space?

 

The only theoretical time travel mechanisms that I've heard even vaguely considered as plausible, have both had physical structures that "anchored" the system in some way.

 

One, is the old "take two openings of a worm hole, grab one and accelerate it so time dilation creates a discrepancy" technique, so the target location is maintained by a physical feature that also travels along with the Earth's path.

 

If I recall, it's considered to be flawed, though I wouldn't be able follow the math if I saw it.

 

The second was a glimpse of an idea on some "future science almost-now" show, which really didn't go into details, that only operated on something to the scale of a single particle. It was supposed to use lasers in some sort of tight spiral to distort a very very very small path of space/time to somehow have a particle end up at a destination before it was sent by traveling back in time.

I assume since the lasers are moving with the planet, so would the particle being transported back in time.

 

Of course, that show didn't even really offer any math, though it may have mentioned "String Theory" so I should probably take it on faith that the idea is sound.

 

 

Of course, if you look at fictional time travel, you are generally popping out of one spot and into another instantly, even if it's just a different spot in time. If you've mastered time to that degree, I doubt the three classic dimensions will give you much trouble, so maybe you could just compensate in the 3D coordinates as well.

[Sisyphus]

But what does "moving at 1/35 C" actually mean? Relative to what? I don't disagree that it wouldn't work, I'm just thinking that the reasons are a bit more complicated (and more fundamental). So you might show up in the same reference frame, but what does that even mean? Is there some traceable continuity between my reference frame (and my position in it) now and at some point in the future? I don't know.

[aguy2]

But what does "moving at 1/35 C" actually mean? Relative to what?

An 'inertial observer'?

I don't disagree that it wouldn't work, I'm just thinking that the reasons are a bit more complicated (and more fundamental). So you might show up in the same reference frame, but what does that[/i'] even mean? Is there some traceable continuity between my reference frame (and my position in it) now and at some point in the future? I don't know.

I don't either, but for some time I have suspected that 'time' and 'space' may be 'equivalent', in that within the context of a Big Bang universe their sum may be a constant.

 

My thought experiment that presumes that traveling 'back' in time would be actually traveling 'forward' spatually seems consistant with my speculation that equivalency is not confined to mass/energy.

 

This an aside and probably gist for another thread, but as long as we are looking at 'relative motion' I have a question concerning the relative motion of Terra (and other orbiting bodies) and the sun:

Seeing as the sun is orbiting the galactic center, to an outside observer, wouldn't the orbital path of Terra be a wave? I have tried to plot the yearly path of the planet in relation to the galactic center and seem to come up with a wave that at one point does a 'loop'. IOW in relation to the center of the galaxy the planet crosses its own path once a year. I have searched the internet but can't find where any competent professional has examined or plotted both the solar and galactic orbital path. I really don't trust my own attempt to plot this path. Do you think you might be able ro help me out?

aguy2

[Ender W.]

The real question underlying all of this is whether or not you move during time travel. Im theory, you would stay in the same place. But time travel has not yet been attained by humans, so any possible affects on your position relative to were you were in the universe before going back are a mystery. The bending of the fabric of space time during travel could leave you somewhere other than were your started from.

[Klaynos]

An 'inertial observer'?

 

You seem to be implying some universal rest frame, no such thing exists, so we're back to, relative to what?

[swansont]

An 'inertial observer'?

 

That's meaningless. An "inertial observer" has no preferred reference frame, and can be traveling at any speed < c. Saying something is moving always has to be referenced to some coordinate system. In this case, the reference seems to be the Virgo cluster, if you are saying we are moving at c/35 toward it. But use a different reference, and the speed is different.

[Baby Astronaut]

aguy2, I get exactly what you're saying. I had arrived at that conclusion, when I made it a habit to always imagine the Earth, sun and planets careening through space in any mind exercise dealing with exact positioning in the universe. Keep going with your thinking.

 

I have tried to plot the yearly path of the planet in relation to the galactic center and seem to come up with a wave that at one point does a 'loop'. IOW in relation to the center of the galaxy the planet crosses its own path once a year. I have searched the internet but can't find where any competent professional has examined or plotted both the solar and galactic orbital path. I really don't trust my own attempt to plot this path. Do you think you might be able ro help me out?

aguy2

Might help to show the math you used, easier to get productive input.

[padren]

I think you are basically using the relative location (such as the Virgo cluster) to express some of the distance variance, not all of it.

 

Essentially, the force of gravity from various sources is changing our acceleration at every moment, and if even if we kept our current velocity (which is irrelevant if we 'instantly' time travel) so as to change our time, but not our location, everything will have gone flying on by or (if you go back) not caught up with where we are.

 

 

If you are in a park, and you travel 10 years into the future, you have to both travel through time and chase the park, covering all the distance the park did.

 

Is that what you mean?

[swansont]

If I understand the OP, it is suggesting that time travel would occur at rest with some arbitrary reference system, and thus Earth would move away if one were to time travel. However, there are problems with this: relativity tells us that there is no preferred frame, and this violates conservation of momentum, because the person is not at rest with respect to this reference system when the time travel would occur; Newton's first law dictated (s)he would remain in motion at whatever velocity was initially present.

 

The best you can do is invoke the non-straight-line motion involved, and say that the earth might have accelerated away from that straight line motion, requiring that you actually "launch" a person while doing this. If you could actually do time travel.

[czimborbryan]

The only reason why the original statement makes sense is because time travel in the science fiction sense does not exits. Only what is in the here and now. Warping time does liitle more than make movement possible. Think of it like the timing of a bicycle drive train; the timing changes whenever the gears shift making the wheel spin faster. Quite literally, the time of the spinning wheel has changed.

[ajb]

The only reason why the original statement makes sense is because time travel in the science fiction sense does not exits. Only what is in the here and now. Warping time does liitle more than make movement possible. Think of it like the timing of a bicycle drive train; the timing changes whenever the gears shift making the wheel spin faster. Quite literally, the time of the spinning wheel has changed.

 

Maybe you should think about closed time-like curves in general relativity and semiclassical gravity. All very interesting stuff. Right now, it is not really understood if time travel is possible or not. There are however, some results that suggest it is not.

[czimborbryan]

A really really crazy though I had at one point is that just maybe time is recorded in physical space like a memory. So, if we were to travel 10 million light years through space, we may be able to find our solar system at it's state 10 million years ago or something like that. At various places throughout the universe we could find our solar system at different stages. The Earth could be saved in time/space infinitely in different geographic areas of the universe.

 

Pretty weird...

[aguy2]

But what does "moving at 1/35 C" actually mean? Relative to what? I don't disagree that it wouldn't work, I'm just thinking that the reasons are a bit more complicated (and more fundamental). So you might show up in the same reference frame, but what does that even mean? Is there some traceable continuity between my reference frame (and my position in it) now and at some point in the future? I don't know.

 

My homegrown calculation of 1/35 C appears to be wildly off. Wiki is currently saying that Sol's total velocity (in relation to CMB) is only about 370 km/sec or approx. 1/840 C.

aguy2

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I think you are basically using the relative location (such as the Virgo cluster) to express some of the distance variance, not all of it.

Although this is speculative on my part (see Is the Universe Collapsing? - 2008 11/11/08 in this forum) I think there is a reasonable possibility that, in a reduced form, the BB event/body may still be exant, and thus serve as a location for estimating relative motion. Other than that, the CMB would also serve.

 

Essentially, the force of gravity from various sources is changing our acceleration at every moment, and if even if we kept our current velocity (which is irrelevant if we 'instantly' time travel) so as to change our time, but not our location, everything will have gone flying on by or (if you go back) not caught up with where we are.

 

Yes, this is the point I was trying to make. If one changes ones temporal location (either backwards or forwards) but not ones spatual location, then to an observer you appear to be where the observer is headed if you traveled back in time, and would appear to be where the observer was, if you traveled ahead in time.

 

If you are in a park' date=' and you travel 10 years into the future, you have to both travel through time [i']and [/i]chase the park, covering all the distance the park did.

Is that what you mean?

 

Yes, in order to stay in the park, the time traveler would not only change his temporal location, but would also have to travel the same convoluted spatual path the park will.

 

Although this is an interesting thought experiment, this does not mean to say that I consider physical time travel to be possible. I don't really think physical time travel is possible, if for no other reason than that the sub-atomic and atomic components of any physical body have quite likely been around since the very early universe, and there could very well be constraints precluding the possibility of something existing twice in the same temporal location.

aguy2

Edited January 11, 2009 by aguy2
Consecutive post/s merged.

[mkruck77]

Why do all the speculations concerning the possibility of 'time travel' presume a non-dynamic staring point, when there is no such thing?

 

Any point on Terra is moving. It is rotating in relation to the planet's axis. It is orbiting our sun. Our sun is orbiting the center of the Milky Way, the Milky Way is moving closer to Andromena, and our glactic cluster as a whole is moving toward a point behind the Virgo Cluster. The total sum of these velocities might be something like 1/35 C.

 

Wouldn't it stand to reason that if you were to travel 35 seconds into the past, you would reappear into empty space approx. 186,000 miles ahead of where you were, and if you stayed in place, 35 seconds latter you would be right back to when and where you were?

aguy2

 

 

You mean 35 seconds in to the future, right? Are you assuming the sum of these velocities to be linear for the traveler (I would think no)

To back up a bit, I don't think the motions within itself matters, as long as there is a system to know each direction of change; probably to the smallest quantum level (quarks) to eliminate any uncertainty. Because symmetries should be unchanged from past to present, you in theory should be able to locate the precise position of the past. You would have to reverse space time to the past position. The hard part to this question is how would you know the future position given uncertainty?

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Consecutive posts merged

You mean 35 seconds in to the future, right? Are you assuming the sum of these velocities to be linear for the traveler (I would think no)

To back up a bit, I don't think the motions within itself matters, as long as there is a system to know each direction of change; probably to the smallest quantum level (quarks) to eliminate any uncertainty. Because symmetries should be unchanged from past to present, you in theory should be able to locate the precise position of the past. You would have to reverse space time to the past position. The hard part to this question is how would you know the future position given uncertainty?

 

Oh, I see...you still have to take the velocities into question to find a given point. I think most theoretical explanations seem to use a fixed position for simplicity, but of course you would have to account for movement.