One simple reason why time travel doesn't make sense

[RedStar]

Everything has a physical and temporal location: a where and when.  Time is always changing, but so is our location.  The Earth is spinning, the Earth is moving around the Sun, the Sun is moving around in the galaxy, the galaxy is moving in some direction.  Temporal locations can work (somehow, not sure how, but they can).  Physical locations really can't work because you'd have to point to a marker or something for you to return to in the past to.

If I were to go back in time 5 years I wouldn't be standing on the Earth.  Depending on the time of year it could be well over a hundred million miles away.  In order to be on the Earth when you go through time you've got to have some marker to take you there, right?  How else will you end up at the spot you want to be at?  For the gates, those are markers, I can buy into that.  But for the Epoch, it's gotta have a marker to connect to.  Maybe the planet?  Any ideas?

[Boo the Gentleman Caller]

I've actually pondered this same point and placed it within my High School Senior Research Paper (which was on the basics of time travel).  In essence, I'm in agreement with you: in order for time travel to occur properly, a device would need a marker of some sort to allow the vessel a direct coordinate to "latch" onto.

Perhaps the world of Crono and friends doesn't revolve around the sun?  We see no seasons, we see no day/night cycle.  Perhaps the people of the Chronoverse don't dookie; we see no toilets anywhere in game!

Oh the possibilities!

[BROJ]

Sorry to throw a wrench into things, but... how do said gates get connected or "latched" to each other in the first place. Clearly there is some mathematics involved(Calculus, Trigonometry, maybe even Chronometry; which computers are notoriously good at, might I add ), but the mechanism, to us, is either undiscovered or non-existent. Throw Heisenberg's uncertainty principle(that kinda screws things up royally) and general probability into the equation and one could only conclude that it is... possible. So, for the time being, we'll have to take some things, such as time travel, for granted in the Chronoverse.

[arpgme]

...Perhaps the world of Crono and friends doesn't revolve around the sun?  We see no seasons, we see no day/night cycle...

We do see the day/night cycle. Remember when Robo help make Fiona's forest in kingdom yr. 600? Then in yr 1,000 the made a camp fire at night.

Perhaps the people of the Chronoverse don't dookie; we see no toilets anywhere in game!

Oh the possibilities!

That's funny.

[Insane]

I know why! It's cus it'll be pretty useless to have a time machine, that dumps you in the middle of space!

[Generality]

Everything is relative. Space isn't a problem if time isn't.

[RedStar]

Sorry to throw a wrench into things, but... how do said gates get connected or "latched" to each other in the first place. Clearly there is some mathematics involved(Calculus, Trigonometry, maybe even Chronometry; which computers are notoriously good at, might I add ), but the mechanism, to us, is either undiscovered or non-existent. Throw Heisenberg's uncertainty principle(that kinda screws things up royally) and general probability into the equation and one could only conclude that it is... possible. So, for the time being, we'll have to take some things, such as time travel, for granted in the Chronoverse.

NASA scientists use a lot of insane math and computers to figure out when to launch something into space, its trajectory, when and how long to use boosters, just to get something to land on the moon or Mars.  To their credit they can get it to land within miles of the target site, but it's not exact.  As the time spent traveling increases and the distance it has to travel increases, the accuracy of their launch will decrease (I think it decreases exponentially towards infinity at some point, but whatever).  There's no way you could accurately go back 65 million years in time and end up even close to the same spot if you relied on math.  There are just too many factors to deal with that we don't know about.  An object that passes by the planet will exert a gravitation pull on it if it is big enough.  If that happens enough times then the planet will be at a slightly different location than one would expect and if you just relied on math you could end up inside a mountain if you rode in the Epoch.  You would have to use the planet as a marker somehow, that's the only thing that would make sense, but how do you use the planet as a marker and be accurate enough so you don't wind up in a mountain!?  We clearly see the topography change over the years.  Islands move, mountains rise and fall.  They would have to be very high in the air and have a way to push the matter at that spot out of the way when they traveled back, because that matter has to go somewhere.

[BROJ]

Everything is relative. Space isn't a problem if time isn't.

That exactly the problem(and why I mentioned Heisenberg's uncertainty principle); one cannot determine both the speed and position of any given quantum particle at any given moment in time.

NASA scientists use a lot of insane math and computers to figure out when to launch something into space, its trajectory, when and how long to use boosters, just to get something to land on the moon or Mars.  To their credit they can get it to land within miles of the target site, but it's not exact.  As the time spent traveling increases and the distance it has to travel increases, the accuracy of their launch will decrease (I think it decreases exponentially towards infinity at some point, but whatever).  There's no way you could accurately go back 65 million years in time and end up even close to the same spot if you relied on math.  There are just too many factors to deal with that we don't know about.  An object that passes by the planet will exert a gravitation pull on it if it is big enough.  If that happens enough times then the planet will be at a slightly different location than one would expect and if you just relied on math you could end up inside a mountain if you rode in the Epoch.  You would have to use the planet as a marker somehow, that's the only thing that would make sense, but how do you use the planet as a marker and be accurate enough so you don't wind up in a mountain!?  We clearly see the topography change over the years.  Islands move, mountains rise and fall.  They would have to be very high in the air and have a way to push the matter at that spot out of the way when they traveled back, because that matter has to go somewhere.

You pretty much just said what I did, only a little more complicated and little different style of approach, save one part; I pose to you a counter-question─if you knew something was traveling at ≥c(speed of light in a vacuum), how would you know where it started and better yet, if it would hit anything along it's trajectory, much less the behavior of ≥c matter.
But skipping that and going to the crux of it all; the after-images aren't really there, so there's nothing to pass through.

[Generality]

That exactly the problem(and why I mentioned Heisenberg's uncertainty principle); one cannot determine both the speed and position of any given quantum particle at any given moment in time.

Human being isn't a quantum particle (kinda). If we assume that an object's movement in time can be manipulated, keeping it from straying afield of its spacial destination isn't a big deal, so RedStar's initial point is not a concern.

[BROJ]

That exactly the problem(and why I mentioned Heisenberg's uncertainty principle); one cannot determine both the speed and position of any given quantum particle at any given moment in time.

Human being isn't a quantum particle (kinda). If we assume that an object's movement in time can be manipulated, keeping it from straying afield of its spacial destination isn't a big deal, so RedStar's initial point is not a concern.

That's the thing with quantum physics─nothing can be assumed... yet. And since quantum physics would be the very keystone on which teleportation and ≥c travel could possibly be based(i.e. taking advantage of sub-atomic particles behavior and magnifying it to the macro-atomic level; worm-hole travel, long range manipulation via quantum entanglement─tractor beam(s), anti-gravity, et al.), one would have to know the community of quantum particles', that would compose you or I, behavior and position in order to achieve, as of yet, unattainable phenomena.

[Ekul]

In most fiction, this is difficult to discuss and very complicated to solve. However, if you think about it, the Chrono Trigger universe in particular may have an excuse. The traveling mechanisms at first are the gates alone. Wherever or whenever this Entity is, especially if it's the planet, the gates were probably created relative to its own position. Since the Epoch travels to the gate specific eras, it's probable that the location it travels to is based on the location of the era's gates.

[Thought]

That assumes that as the planet moves around its axis, the sun, the center of the galaxy, and the center of the universe, it's physical location (that is, its 3-dimensional location) changes. Why are you assuming that?

Imagine you have a sheet of paper that you draw a graph on. On that graph, you mark a point at 2, 2. Then you put that paper in your backpack and walk home. Is that point still at 2, 2? Now you might say that such an example isn't the same, the point did move. To which I say, it moved in 3-dimensions but did that point ever move in its 2-dimensional universe?

Or consider a computer screen. Move your cursor from left to right. Did the diodes of the screen move, or did just the perceived image of the cursor move?

My point is, just because something is moving in relation to other things on a 3-dimensional scale, that doesn't mean that the movement on a 4 dimensional scale is actually significant (or occuring at all).

[VincentGAU8]

That assumes that as the planet moves around its axis, the sun, the center of the galaxy, and the center of the universe, it's physical location (that is, its 3-dimensional location) changes. Why are you assuming that?

Imagine you have a sheet of paper that you draw a graph on. On that graph, you mark a point at 2, 2. Then you put that paper in your backpack and walk home. Is that point still at 2, 2? Now you might say that such an example isn't the same, the point did move. To which I say, it moved in 3-dimensions but did that point ever move in its 2-dimensional universe?

Or consider a computer screen. Move your cursor from left to right. Did the diodes of the screen move, or did just the perceived image of the cursor move?

My point is, just because something is moving in relation to over things on a 3-dimensional scale, that doesn't mean that the movement on a 4 dimensional scale is actually significant (or occuring at all).

That is relativity, yes?  But then i thought that a 3-d space is actually moving on a 4-d axis..
If that point 2,2 (in reference to its 2-d universe) moved in its 3-d universe but not its 2-d universe, didn't it still move on its 4-d axis? Then it would become point (2,2)₁, while its initial location in reference in its 4-d frame would have been point (2,2)₀ ...

[Thought]

If I am understanding you correctly, yes. However, my point was, no matter how it travels in extra dimensions, from those dimensions the lesser dimensional locations are quite easy to determine. This is just a possible counter to the supposition that time travel requires one to teleport between time periods (a 4D distance) and the physical location, in relation to the universe, of where one entered and where one exited (a 3D distance).

All that might be bunk, admittedly, as we don't know how 4th dimensional travel would be effected by 3 dimensional movements.

[BROJ]

All that might be bunk, admittedly, as we don't know how 4th dimensional travel would be effected by 3 dimensional movements.

Bah! The only archetype of time travel(inasmuch the Gates or the Epoch have been documented) is in the form of 'gate' travel, in that, two discontiguous point of space-time are jointed by a 1D/2D 'gate' perpendicular to the ship/traveler; so there shouldn't be any worry about relativistic movements(although the Magus gate appears to be a curious exception.).