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Time Travel without Space Travel?

G

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If I "merely" go back in time, say 10 years, will I come out at the same point in space? If this is the case, then I might end up quite a distance from Earth. Since our solar system is revolving around the center of our galaxy, and our galaxy is revolving with respect to the local group of galaxies, I might well end up millions (if not billions) of miles from Earth.

Maybe this is what happens to time travellers: They pop-up in deep space and die before they can shuttle back to a livable planet!
 
Excellent point which we have touched on earlier, and one of the reasons I am NOT a believer in time travel. Defining just where that "point" in space "was", that you want to go to in time, is virtually impossible.
 
Re:Re:Lee\'s Response

Hi

If we are able as we are, to predict where Pluto will be in say 3 months, Why cant we LEARN where the earth WAS by looking at where it is and where it is going then reverse back the path, Couldn't today's computer's do that?

Sure the calculation's may not be EXACT, But wouldn't there be room for
a little error?, Other than landing in fire etc.

EXAMPLE: When reading a map, Should your calculations be say 1 degree out, that error will increase the further you travel (Cone effect), With the point of the cone being the starting point.

I dont really understand how predicting (With today's Computer's) the where abouts of the earth at any point in time.

What I know of this subject & related area's of it, really are lame compared to what I have read here, So please excuse my some what infintile questions & thoughts.

Rob (Just a Dreamer)
 
This idea seems to hold true only if you insist on relocating yourself in the "same" physical locale on earth that you departed in time from. By choosing only a generalized area in space for your arrival point, and then journeying back to earth using more conventional transport, the problem disappears.
 
Re:Re:Time Travel without Space Travel?

If you go to this page:

http://www.madsci.org/posts/archives/dec97/874948869.As.r.html

you will find the best estimate I could locate for how fast one is traveling through space by just standing on the earth, i.e. 370 km/sec.

If you go back in time (say about 10 years, and why would you make a time machine if you didn't plan on going back at least that far? enough to buy a few shares of the most underpriced stock) then if all you did was travel back in time, when you got back, the earth will have moved:

370km/sec*3600sec/hr*24hr/day*365days/yr*10yrs = 117 billion kms !!!

Now if you can't go faster than 370km/sec (or more like 740km/sec) it will take you 10 yrs to get back to earth.
 
Re:Re:Re:Lee\'s Response

Theoretically, you are right. If we can create a time machine that can also move through space while it is moving through time, then we should point it in the direction where Earth WAS. However, since the Earth is travelling about 370km/sec (230mi/sec) through space, this could be rather difficult. That speed is about 20 times faster than a Saturn V rocket, the fastest thing we have created to date. If it took our time machine 10 years to go back 10 years in time, then we would need to be travelling at 370 km/sec to stay near Earth. If we wanted to take less time to go back in time, then we would have to go much faster. For example, if you wanted to go back in time 10 years, and only take a day, then you would have to be travelling at about 370*3650 km/sec, which I believe is faster than the speed of light!

So the only hope it seems is some sort of naturally occuring (or artificially created) wormhole that can take us back in time and space simultaneously. I believe that Pauli of Pauli Exclusion Principle fame was working on the equations to see if creating an artifical wormhole was possible (I saw a lecture on this at CalTech quite a few years back.)

At the time, it seemed to him that quantum fluctuations might just cancel out any time reversal effect so he wasn't overly optimistic, but they were still plugging through the equations.
 
Re:Re:Re:Lee\'s Response

Good point.

We can calculate where Pluto will be in 3 months RELATIVE to the Sun and to us WITHIN the context of our solar system. We can't calculate where it will be in the overall universe however since the problem gets unsolvable.

The solar system is revolving around the galaxy in what is to us a rather northerly direction. (Toward the Star Vega to be more precise.) The axis of the solar system is almost perpendicular to the plane of the galaxy. As such, the Milky Way appears as a wisp running north/south (approx) in the sky. The Earth axis is ROUGHLY parallel to the solar axis.

Our northerly movement toward Vega is actually our solar system orbiting the Galactic center. Vega is "ahead" of us and we are not closing in on it to any degree that I am aware of. Out in the Saggitarius Arm where we are, this Galactic orbit takes about 100k years per cycle.

We can probably calculate points up to this level fairly acurately, but from here on up it gets worse.

The milky Way is an element in a small cluster that includes the Andromeda Galaxy and the Magellanic Clouds. They are slightly receding from each other to a degree that is only estimated at this time. Worse yet, this little group is part of a greater cluster called the Virgo cluster which is itself a peice of an even larger super-cluster. Our little expanding cluster is also moving as a unit in another direction entirely within the larger cluster and so on ad infinitum with the entire universe expanding as a whole.

Pretty soon, it actually gets impossible to determine exactly which direction we 'really' are going. Defining a fixed point becomes an exercise in frustration.

The Time Machine better be able to figure all this out or your original problem is just as you stated it. Where ya gonna pop out huh?

I DO NOT volunteer for the first trip. :)
 
Re:Re:Re:Re:Lee\'s Response

I meant to say "the problem as nolo stated it"....sorry.
 
Re:Re:Time Travel without Space Travel?

See my post just below...

It would be my contention that you can't even get close.
 
Your 740 km/sec upper velocity for the earth is the equivalent of around 3 million KPH. An astounding speed from an engineering perspective in this time, but surely not unimaginable in the not so distant future. You seem to be a little biased towards the notion that time must be tranversed by "riding" inside a piece of hardware, that in and of itself carries you and your equipment through time. A different perspective offers the notion that by simply (?) maneuvering oneself correctly in relation to a sufficiently powerful gravitational field, ( F. Tipler suggested rotating neutron star material in the early 70's) you can exploit the local distorted space/time topography to your own advantage, for movement in closed timelike loops. Using this method one travels in space and time simultaneously. The Tipler et al paper is well worth the read for those so inclined.
 
Re:Re:Time Travel without Space Travel?

See my response to Rob.

If you have a time machine of the sort where you get into a box, set the timer, then get out, it might be impossible to make a practical time machine.

In my response to Rob, I suggested that you might have to go faster than the speed of light in order to get back to the right place at the right time if you want to take a reasonable amount of time (~ 1 day) to go back in time (~ 10 yrs).

So you are right in that the only reasonable solution seems to be a naturally occuring (or artificially created) time/space distortion such as a wormhole.

I hadn't heard about the neutron star idea. Are there any in our vicinity or are they an impractical distance from us?
 
Any star with a mass greater than between say, 1.4 and 3 solar masses, is capable of eventually collapsing and becoming a neutron star. The problem really isn't their distance, it's the difficulty you would have constructing a mega-device, kilometers long, that consists of star material having a mass of billions of tons per cubic mm, and then proceeding to spin the device at a rate of several hundred thousand KPH. An average neutron star runs several kilometers in diameter and Tipler worked out that you would need to "sculpt" (my word..not his) several of these together into a cylindrical shape to achieve your ends. It's the combination of an extreme gravitational field plus the rotational movement that produces the distortion in space-time. From a current engineering perspective the notion of using neutron star material for construction is pretty laughable. However that dosen't take away from the fact that the multiverse dosen't care if the extreme gravitational field is natural or man-made, it will produce predictable and exploitable distortions in spacetime regardless.


Jon Formet
 
Re:Re:Time Travel without Space Travel?

Just out of interest, are you still purporting to be a time traveller yourself?

Or have you given up on the futile hope that anyone will take that seriously?

If you are a time traveller, do you actually understand the 'true' nature of time?

Is it a physical quantifiable property of the universe, or simply the way that we perceive the universe and thus only a human linear 'illusion' in universal terms? In other words, is 'time' something that we observe, or something that we observe with?

This is one fundamental question that I would love to know the answer to.

If time is a 'universal' property and not just a human one, could you tell me what the actual 'timing' mechanism that you have utilised is tuned to?

Radiactive halflife etc?

Cellular decay or some other biological function? (limited to your own lifetime so I guess that's out.)

Some other presently unknown process?

However, if 'time' is actually no more than just our perception of the Universe, I expect that said 'timing' mechanism is irrelevant. It would be attaching 'universal' relevance to something that does not actually exist 'universally'.

If that is so, what method did you use to 'leap' beyond linear perception(time), select a point to re-enter 'linear perception' and then do so? Could this somehow be drug induced?

I'll be surprised if I get an answer to this to be honest. Please surprise me..
 
That is an interesting question that a couple of us have tackled before. I feel that it isn't necessarily as cut and dry as you may think though.

It raises an extremely fundamental question that I doubt anyone can answer.

What is the actual 'true' nature of the universe?

Yes, we know bits and pieces, but can we say or prove exactly how it all works, what the 'true' nature of it all is? You may as well ask the same fundamental questions about God..

We don't understand the nature of time (quantifiable universal property or just our perception?) and neither do we understand the true nature of space.

Are we sure that we can rely on our system of spatial co-ordinates?

We perceive the universe as an expanding entity. Galaxies, stars etc are all moving apart. We suppose that these observable elements of the universe are all there is. Thus their positions can only be determined in relation to each other.

What if we are missing something? Here's a question that may be related.

What is dark matter? Isn't it invisible(undetectable) and isn't it supposed to account for about 99% of the volume of the universe? (I'm not completely sure of that figure, so don't hold me to it..)
I guess it thus came about because we can only account for 1% of the universe's mass, rather than through any observation of dark matter itself. Anyway...

What if this is the missing part of the puzzle? What if this is the underlying foundation, the basic fabric of the universe that everything that we know exists within? This could throw a very different light altogether on 'space' as we know it.

Here's an exotic theory that I remember from somewhere or other..

Imagine that space is like the surface of a balloon. 'Embedded' within this surface (anchored/fixed if you like) are the planets, stars, galaxies - everything that we can observe. (I'll assign dark matter as the surface at this point). We obviously can't detect this surface, yet it is the medium in which everything exists. (I supose that you have to try to imagine this surface existing in 3 dimensions rather than 2...but 'surface' is the nearest metaphor, so you get the picture)

Imagine the expansion of the universe in terms of steadily blowing air into the balloon. In relation to each other, the galaxies are moving apart(our system of spatial co-ords comes into play).

What about the position of the galaxies etc in relation to the undetectable 'surface' (dark matter) though?

The answer is that in relation to the medium in which they exist, they haven't moved at all. It's a matter of perspective. If you had a system of 'true' universal co-ordinates (taking the dark matter/underlying medium/surface of the balloon/ether into account) everything is always in the same place. This is because you are 'riding' the 'surface' of the universe (existing within it) along with everything else.

This all obviously depends on galaxies etc being fixed points on the 'surface' of course. Imagine everything as a point 'drawn' on the surface of the balloon.

It appears that we would have a seemingly paradoxical situation. Everything is moving apart, at the same time as not moving at all. However, once again it depends on your perspective.

What rammifications would this have on our perception of time? On time travelling and arriving at a different point in space to the one that you left?
I think that it's difficult to accurately predict these kind of effects of such an excursion, when we truly don't understand the 'real' nature of either space or time.

I hope that the intent of this message isn't misunderstood.

If it causes anybody out there to question the wisdom of putting too much stock in our present relatively limited understanding of the universe, epecially when dealing with the kind of matters that we do hear, then it has fulfilled it's purpose.

Just think of this as a mental catalyst, or maybe a mental laxative
happy.gif
))
 
There seems to be an assumption that a time machine would be at rest relative to the earth. Why should it be? You, the earth and everything you use to build build your time machine are all hurtling through space together. What would cause that to change?
 
Re:Re:Re:Time Travel without Space Travel?

Hello Simon B. If you re-read my initial post you will recall that I have no expectation whatsoever that anyone will take me "seriously", or believe that I'm a temporal traveler. There never was a "futile hope" to begin with, in fact, I know for a certainty that these discussions, and their subsequent fallout, have virtually no impact at all on the developments to come in this loop.


And now to your "question"..............

The notion that somehow time is an illusion or an artifact of human perceptual systems was laid to rest by Einstein almost 100 years ago, relative to this m/e. Time is as much a naturally occurring feature of the multiverse as matter, energy or space, and is just as amenable to the application of proper engineering techniques as the other three. In our time your search for the "true nature" of reality is regarded more as a statement of certain religionlike beliefs that you already hold regarding the multiverse. The search for a "Universal" Truth and Time, is best persued by specialists such as philosophers and theologians, and shouldn't be allowed to interfere with ongoing scientific purposes. The quest for the "real" can add to general overall knowledge, but it should not be used as an excuse by individuals to supress specific scientific inquiry. Much of the time, unlike MEST, science and religion are separable entities. I doubt this is the "answer" you were looking for, but then again as I said before, we believe you are making a statement regarding your own expectations rather than asking a "question."

P.S Your seeming fascination with "drug" induced mental states is a quaint and highly dated marker for your particular era.

Jon Formet
 
Re:Re:Time Travel without Space Travel?

I suppose if one assumes that any form of time travel somehow 'automatically' solves the problem of the position any object occupies in THAT time, the positional question goes away.

Yet, the problem persists for me because regardless of what we 'do not' know and have not yet discovered, we still DO know that all bodies in the universe are in motion in some way. We know this because there's an old thought experiment where a hypothetical space is occupied by only two bodies. The distance between them is changing, but it is impossible to determine whether one is at rest and the other moving, or if BOTH are in motion, because there is NOTHING else to compare the two of them to. You can calculate the velocity (or even the acceleration if the velocity is not constant) of their relative motion to each other without even CARING which one is in motion or if BOTH of them are. The velocity measurement will be knowable, regardless. Once you add a third body to the problem, you can at least use IT as a frame of reference for the other two, or can you... It doesn't even matter which one you choose, it will still serve as this frame of reference for the others...or will it? You will be able to tell which of the other two is in motion, (or perhaps both) RELATIVE to your current position on the THIRD body, BUT... now the calculation of relative velocities and even exact position already becomes impossible to analyze. This is the classic "Three Body Problem" which you can study in detail at:

<http://www.pass.maths.org.uk/issue6/xfile/tindex.html>

Eventually, the more bodies you add, it becomes downright impossible to devise any formula that can account for all of them. In fact at 4 bodies, we're already beyond hopelessly lost.

Now imagine the universe with its 10^billions power bodies and the impossibility of finding ANY given point in it that would represent WHERE a point on the Earth WOULD HAVE BEEN or WILL BE at some specific point in time. You have no frame of reference to start from that you can count on as a verifiable point to even measure your hypothetical projected point from. Including the chair you're sitting in right now.

Like I've said elsewhere, when the time machine is built, I DO NOT volunteer for the first test mission.

Thanx.
 
P. S. 3 body problem site.

For some reason my link didn't paste right in the above post so here it is:

http:/www.pass.maths.org.uk/issue6/xfile/tindex.html

for the Three Body Problem

Sorry for the goof up.
 
There is no "automatic" solution to this problem involved. Solving normal problems in applied temporal-spatial navigation is not something late 20th century physics can even be about. Plotting point to point trajectories, through the myriad of myriads of convolutions that form near extreme gravitational fields, is possible only through the further development of what is referred to in this time as quantum computing. Nature isn't shutting the door in these cases, it's just forcing you to refine the ability of your computational tools to the extent required to store and manipulate enough information to achieve your desired ends.
Even in this time, scientists like David Deutsch at Oxford are envisioning machines that will store and manage as many bits of information, as there are atoms in the "observable" multiverse. Try to imagine the problem solving ability of a machine where the equivalent of every "chip", had that sort of capacity.


Jon Formet
 
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