Funny, I would say that we leave a trail of ‘ourselves’ behind us through time, such that to an observer stationary in time, I would perpetually exist, frozen in the position I was in at that time. “Myself at 3:43 PM mountain time on 01/09/2009” can be described as sitting in my chair in my work cubicle - this is an invariantly true description of myself-at-that-time, regardless of what I might do at other times later, not a statement that was only true for a blink of an eye.
So, fourth-dimensionally speaking, we are extruded worms tracing a path through the years from the place and moment of our birth, to the place and moment we are in now, and perhaps to the place and moment of our deaths. (Depending on whether the future is ‘already written’ or not.)
One wonders how the inanimate objects that made up the ‘empty world’ managed to outrun the living things, in order to get to the future early and make up a place for the time-traveler to wander around in.
Of course, any consistent notion of traveling to the future presumes that you don’t get to ‘arrive’ until the rest of the world gets to that time-point the old-fashioned way, by aging. Or put another way, I am going to be somewhere a few seconds from now, and so somebody who hopped forward a few seconds would find me there. It’s that or land in the middle of infinite nothingness, I’d think.
Seconds are a human concept, just like inches are, but the distance being measured by inches is real and independent of humans (all existence wasn’t 0 size before we came along) and the fact that the state of the universe seems to change in what seems to be a consistent, constant-speed manner is independent of humans as well. Our memories bear this out - we remember that the sun wasn’t always in the position it currently is in in the sky, and that it seems to have moved in a cyclical motion at a consistent speed - a behavior that requires objective time.
Not just clocks, but all objects are effected by relativistic effects. (And to the fast-moving observer, the clock he carries runs at the same speed it always did, and clocks he’s flying past appear to be moving faster, assuming he can see them at all. Incidentally.)
Put some busquits in the oven. Check on 'em after 15 min. Close the door, and check on 'em again after another 15 min. The change that has taken place is not because of the time, but because of the heat of the oven and the effect of time.
As for the time dialactic, drive down a highway and notice how your vehicle traverses the landscape near to you at a faster pace than a landmark in the distance. It’s relative.
GPS satellites must contend with the distance between them and mother earth, and the effects of the time it takes for communication to take place.
Outside of the effects of time, you move into the realm of theory.
What you have just described is not time-travel, but the effects that traveling at near light-speed has on the traveler.
Time has not slowed on earth, only from the traveler’s relative perspective has time seemed to slow, and that was due to the physical effects of movement.
All this proves is that the accelerating reference frame has physical effects. We use our concept of time to describe those effects.
This is what makes time travel impossible, in my mind. If time is not a spatial dimension, how can we “go” there? If it’s not spatial, it’s just a concept.
Hehe, true. I forgot to further expand that I thought the same thing, the objects and world wouldn’t be there either. Time travel (assuming time existed and you could travel through it) would just put you out of sync with the universe into a void or into some other universe altogether.
What do you think time travel would be? It is your ability to get from one point in time to another and do so in a fashion separate from earth bound people. So, you move 30,000 years into the future in a few seconds and everyone else takes the long way around (30,000 years). As noted if you dragged a traversable wormhole along with you then you could step back 30,000 years. Back and forth, 30,000 years at a go.
I call that time travel. YMMV
Note that this also avoids the issues of meeting multiple copies of you at different times. There is only one you popping back and forth. So, at least one paradoxical situation solved.
Yeah I suppose I could agree with you that this is technically time travel, and probably the only possible way to do it. I don’t buy the wormhole theory though, this would be a one way trip. Do we really know that human aging would be affected the same way or that a human could even survive the trip? That’d suck if you grew old and died in what seemed like a few seconds.
Of course human aging would be affected the same way. If the clock in your spaceship says you have experienced 1 minute while traveling through space, you’ll have aged 1 minute. The duration experienced by people back on earth is irrelevant. When you step out of the spaceship you’ll be 1 minute older no matter whether you’ve traveled 1.00000001 minutes into the future or 1 million years.
With all due respect, I think you’re trying to draw a meaningless distinction here. If time is effecting change, then change is occuring because of time.
No, I am saying that time is not a “literal and physical thing”, but a method of measurement created by mankind.
In the bisquits in the oven analogy, it is not time that is effecting change, but the amount of heat that the bisquits are subjected to that is effecting the change.
inches, feet, and miles measure length.
seconds, minutes and hours measure time.
inches, feet, seconds, and hours are human constructs but you cannot deny the existence of length and time. i feel silly just in even responding.
if you want an analogy to prove that time has an effect on things, think of time as an additional dimension of an object. There’s a plane flying somewhere. you can note its position in x,y,z, the traditional dimensions. However 5 minutes later, it will have another set of positions. Is this to say that the plane is existing in multiple instances? no. there’s a factor of time. the plane moves. it cannot move without the passing of time. i… i’m done.
I answered this in post #78 above. Einstein’s theory of relativity is one of the most successful and well tested theories ever (I think only Quantum Mechanical theory has been more thoroughly tested). In it Einstein lays out the notion of spacetime rather than just “space”.
In short time is a “literal and physical thing”. If you can debunk the Einstein have at it and good luck.
Time itself runs more slowly. We are embedded in time. Your clocks will run more slowly, you will age more slowly, everything will be in slow-mo. Everything.
Time as it appears to you will seem normal. You will feel like you are living 1 sec = 1 sec. But if I could look at you from earth I will see you as moving in slo-mo, really really slo-mo. It’s the frame of reference thing again. When you come back to earth your clock will say only a few minutes have passed. You will have aged only a few minutes. Your cookies in the oven will only be partly baked. Yet some thousands of years (or more or less depending on how fast you got yourself moving) will have passed.
This has been experimentally proven. It really works this way.
I do get the point. I can accept that it’s probably possible near light speed to “time travel” forward, thanks to Einstein’s theory and experiments thus far on how it affects various physical things. I think saying everything is slowed is a bit premature (have we really tested everything) but it’s also something I could accept as true anyway. Until we put a human in a near light speed vessel and they come out ok a few years later (in the external time frame) I wouldn’t say this has been proven.
However, the above being true does not negate my position on time itself being only a concept we use to describe these things. My point of view is that in the universe, things are only as they are at that moment. There is no record of how things used to be, such that you could somehow go there and see it as it was. Once something happens, it cannot be undone, nor can it happen again, nor is it recorded in some 4th dimension. No wormholes or bending space-time. We can remember how things were, and we use our concept of time to describe that, but just because we remember it doesn’t mean it somehow still exists that way.
It’s really hard to explain, because time is such a deep rooted concept in who and what we are and how we view the world.
No, it is not “premature”. It really, really works this way. They have put hyper accurate clocks on a plane and flown them around and witnessed time dilation. They have put hyper accurate clocks at the top and bottom of a water tower and witnessed time dilation (the closer you are to a gravitational center [e.g. the center of the earth] the slower time moves as the light slows down climbing out of a gravity well). They also use relativistic calculations to allow GPS satellites to operate accurately. If they didn’t GPS would be inaccurate.
You are embedded in time just as you are embedded in 3D space. Space itself can be warped (also experimentally proven and the central tenet of General Relativity). Time itself can likewise be warped as has been described above. If time itself warps around you then you go with it. You cannot separate yourself from it. It’s like being stuck in a river. You can move around in the river to places where it flows more slowly or more quickly but you cannot get out of the river.
Well, we have noted how you could, in theory, build a time machine. Granted it assumes some hypothetical things such as traversable wormholes. However, theory does allow for wormholes so they are not made up things. They pop out of some solutions to General Relativity equations and so far General Relativity has been spot on. There is no reason to currently doubt it. Every experiment done so far it has been right on the money. Admittedly a traversable (one you could travel through) wormhole seems to have some daunting problems…we just do not know yet.
If you study Quantum Mechanics even a bit you learn very fast that your intuition of how the Universe works is completely flawed. QM is disturbing on many levels yet over and over and over it has been shown to be correct. Just because your intuition on how time “should work” tells you one thing is no guide for how it really works. That is partly why it is so much fun to ponder…really bends the brain. Special Relativity, like QM, has some profoundly counter intuitive results (although I will say that SR actually does start to make sense once you get a handle on it…QM never fails to disturb).
This is the biggest issue I have with the conventional definition of time travel, which nobody has quite addressed yet…
Say I’m sitting around my house one day, and suddenly a Guy Who Looks Like Me pops out of thin air.
ME: Who the hell are you?
GWLLM: I’m you, from the future.
ME: I don’t believe you.
GWLLM: You will tomorrow, when you get in the time machine and go back to have this conversation with yourself.
Guy Who Looks Like Me vanishes. Assuming he was telling the truth, I now have no choice but to get in that time machine tomorrow, and to say those exact same words to myself when I do. Say the machine doesn’t look safe to me and I refuse to get in. Well, that’s not really possible, is it, because the conversation with my future self already happened.
Now let’s say I decide to go forward a day. I hide behind a potted plant and watch myself eat a tuna sandwich for lunch, then travel back to today. Tomorrow, I say to myself, you know, I kind of feel like Spaghetti-O’s for lunch. But that’s also impossible because the tuna lunch has already happened. I was there; I saw it.
These scenarios not only defy any sense of logic, they also bring into question all concepts of free will and choice. In essence, it assumes that everything that will ever happen has really already happened and we are all powerless to do anything about it.
