Time Travel

[Ice wolf]

Re: Time Travel

(the end of mythosis)

I may be wrong, but I think you mean mitosis.


BTW, I found this: Scientists say that you can't time travel. I haven't actually read it, but I need to go to sleep.

[Tps222]

Re: Time Travel

That link just states that Scientists say we can't do it yet, but it's possible.

What a terribly misleading topic header.

Also, I like the example they provide at the bottom concerning time dilation.

Although I'm more interested in how time is viewed at the event horizon of a black hole. That's when **** gets crazy.

[rzr]

Re: Time Travel

How did mitosis get into this conversation? I see absolvely no conceivable way where it would fit into a debate about time travel.

[Lipidman]

Re: Time Travel

No one said mitosism (is that correct?) was related to time travel. I suggest you read Verructer's post again.

[rzr]

Re: Time Travel

I read Ice Wolf's post.

[benguino]

Re: Time Travel

Time should be treated as if it was another dimension. To find someone in a helicopter for example you need to know the latitude (dimension 1), longitude (dimension 2), altitude (dimension 3), and the point in time (dimension 4). See each piece of matter can only be at one latitude, one longitude, one altitude, in one point in time.

[Reach]

Re: Time Travel

You've got the direction of the logic wrong there. Einstein said that if you could go at the speed of light, your subjective time would seem to stop in relation to objective time, and if you went faster than the speed of light, your subjective time would seem to go backwards in relation to objective time. You therefore can end up with something that to you seems like time travel to the future, but it isn't fundamentally different than the way that in 10 minutes, you've time travelled 10 minutes into the future.

IE. If I travelled faster than the speed of light, I would seem to the rest of the universe to have arrived at my destination before I actually left. This is actually already something that is documented. The few people who've spent the most time in space out of anybody (And thus, more time moving at incredibly high speeds [leaving the gravity well, being in orbit etc]) are actually a fraction of a second younger than everyone else by objective time. Years of moving that much faster have only added up to a 0.01 second difference, but the difference is already there and measured.

He wasn't entirely wrong. Faster than light travel is equivalent to time travel in GR, and Einstein said it was impossible. If you move any piece of information from one point to another faster than c, in some reference frames the information would appear to move backwards in time, which... doesn't make sense.

What you're saying has been documented, but not faster than light travel, since it's impossible. Zero mass particles in a vacuum will always travel at c, like photons...however, you can't accelerate a non zero mass object to c or beyond c because it requires infinite energy. So, we don't have to worry about this at all.

Absolutely everything in the universe that is moving undergoes Time Dilation, specifically because any such movement alters your frame of reference. It can be described most simply by 1/Sqrt(1-v^2/c^2) as the change in time, where any change in v will cause reference change at some level. This happens because of the energy you are required to gain to produce this change in v, where E=mc^2 also abides by the same reference frame law (E=mc^2/Sqrt(1-v^2/c^2).

This is not something that is disputed, so your friend is absolutely right. The phenomenon is used in practical applications as well - for example, in image projection in things like TVs. Because the electrons used to produce these images move at relativistic speeds, we have to correct the image for Lorenz contraction which would distort it.

This phenomenon isn't Time Travel though, and I still doubt it's possible. <_>

[rzr]

Re: Time Travel

But 'time' is just a concept created by humans to make their lives more efficient. 'Time' to a human is much more exponential to us than to a tree.

If you take an intelligent being (other than humans making this completely hypothetical) and give it a watch. Now, this being's average life span is... let's say 1000 years (years being a human measurement). That being, we'll call it x, looks at its watch and sees the minute hand tick by. The minute hand to this being represents much more than sixty seconds. Because the average moment for this being (moment being a particular situation) is 6 [human] months than a minute takes much less time up. It would seemingly fly by.

In conclusion to this rant, time itself is simply an inaccurate measurement because it was created using the average span of one mind (being humans).

[devonin]

Re: Time Travel

Did you even read my post involving the distinction between time and Time?

To something that lives 1000 years, our use of seconds as a significant span of time might seem silly, but that doesn't mean that one second for us is actually a different length of time than it is for them. Time is Time and passes at what amounts to a fixed rate for everything. How we choose to set up time to understand how Time is moving is arbitrary and human invented yes, but that's like saying that we invented the word "tree" so there's not really such a thing as trees. You can say there's not necessarily such a thing as a "tree" insofar as "tree" is just a word we apply to a bunch of things with the characteristics we've defined as "treeness" but you can't say the physical object isn't still there in front of you no matter what you call it.

We may say "That's a cat" and someone who speaks french says "c'est un chat" and we're using differenet terminology, but we're still referring to the same actual object. WHether you measure in what we call 'seconds' or what we call 'months' as your shortest length of time that means anything to you, Time is still Time no matter what time system you apply to it. Do you see what I'm saying?

He wasn't entirely wrong. Faster than light travel is equivalent to time travel in GR, and Einstein said it was impossible. If you move any piece of information from one point to another, in some reference frames the information would appear to move backwards in time, which... doesn't make sense.

I was more looking at the fact that he parsed it like "Einstein said this about time travel: Time dialation at extreme speeds" when I was saying he was more like "Einstein said this about time dialation: It would seem to be like time travel"

Moving faster than the speed of light is just the most -efficient- form of "travelling to the future" because you get a rate better than 1:1 of subjective timebjective time. So just because we think going faster than c is impossible just means the most efficient manner of such travel is closed off to us.

We've already established that miniscule differences already exist between certain people and everyone else, so the thing is happening, but I do agree that while it appears like time travel to the person doing it, the effect to almosty everybody else would be that the person was moving only very slowly, not that everyone else was somehow fast forwarded.

[Verruckter]

Re: Time Travel

Nono I get what you're saying, and to one respect, time is a human construction. The issue is that you seem to be thinking that Time (capital T) is a human construction, which I don't think it is.

Time exists objectively, and humans constructed time (Where we measure things as happening over time [years, hours, seconds, picoseconds and whathaveyou) as a means of mutually understanding and recognizing what is going on. We needed a consistant labelling system to understand it, but that doesn't make it any less real on its own.

But what if all in all, the only real "time" was the one we used on our watches? I mean, the three first dimensions we can see, touch, taste, hear and smell (yes, that's right, the reason why you can smell or taste a flower is because it exists and has a shape in three dimensions and fits in the cavities of your nose, sends signals to your brain, etc etc).

Time? The only way we can measure it is by using a timepiece, but we still can't see, touch, taste, hear or smell it. There are no particles that constitute time (as far as I know). We invented a system, based on the moment from where the sun rises (or sets) to the moment where it rises (or sets) again. We divided that into 24 hours, and then minutes, seconds, etc. What if there was no day and night cycle (of course life would not spawn, but let's say it's possible)? What if there wasn't an impression of movement, of change due to the degradation of things and the spawning of new things? Well, humans wouldn't know what "time" would be and probably never would of though about it.

Of course, this improbable image is just to explain my point, but I think you can understand.

[devonin]

Re: Time Travel

Time? The only way we can measure it is by using a timepiece, but we still can't see, touch, taste, hear or smell it.

We are constrained by the fact that we percieve things as a series of moments flowing together into a stream of events. You can measure time easily. Set up a camera, film for an hour, sit down and watch the video. You can -see- the movement of time forward from the fixed point you started filming.

Can you hear length? Smell depth? I'd argue that you can -see- time as easily as you can see the width of somthing. Why does it have to be measurable by -all- senses in order to count?

What if there wasn't an impression of movement, of change due to the degradation of things and the spawning of new things? Well, humans wouldn't know what "time" would be and probably never would of though about it.

They wouldn't know what time was and woudln't have thought about it...BUT IT WOULD STILL BE PASSING...to me this seems to back up my claim that Time is an existing thing outside the bounds of human time measurement systems.

[Verruckter]

Re: Time Travel

We are constrained by the fact that we percieve things as a series of moments flowing together into a stream of events. You can measure time easily. Set up a camera, film for an hour, sit down and watch the video. You can -see- the movement of time forward from the fixed point you started filming.

No, you've filmed the result of all the changes that occured in that lapse of conceptual time.

Can you hear length? Smell depth? I'd argue that you can -see- time as easily as you can see the width of somthing. Why does it have to be measurable by -all- senses in order to count?

Sound waves are tri-dimensionnal. Molecules which by sticking to your nasal cavity create a signal sent to your brain are tri-dimensionnal. Of course you can't smell the width of a steel bar, but without three dimensions (or at least two), none of our senses work. Time, on the other hand, does not affect any of our senses, and is not tangible. Instruments can't "take" or "pick up a piece of" time and anaylse it.

Anyways, I suggest we stop getting away from the main subject. Clearly, devonin, you understand my point and I don't think neither of us will be able to change each other's mind so let's not waste our time.

[devonin]

Re: Time Travel

Why does something have to have a physical presence to exist? You can't "take" or "pick up a piece of" gravity either, but I'm pretty sure that's real.

[Verruckter]

Re: Time Travel

Why does something have to have a physical presence to exist? You can't "take" or "pick up a piece of" gravity either, but I'm pretty sure that's real.

Hmm, you do make a point. I'll think about it and come back to you.

[Reach]

Re: Time Travel

I'm leaning towards Devonin's explanation for this one.

ime? The only way we can measure it is by using a timepiece, but we still can't see, touch, taste, hear or smell it. There are no particles that constitute time (as far as I know). We invented a system, based on the moment from where the sun rises (or sets) to the moment where it rises (or sets) again. We divided that into 24 hours, and then minutes, seconds, etc. What if there was no day and night cycle (of course life would not spawn, but let's say it's possible)? What if there wasn't an impression of movement, of change due to the degradation of things and the spawning of new things? Well, humans wouldn't know what "time" would be and probably never would of though about it.

Quantitative descriptors of behavior or phenomenon can exist without the necessity to see, touch, taste, hear or smell them. Devonin was going in the right direction with the length analogy - it's a measurement that we impose on any object, but it is also an *intrinsic* characteristic of that object, much like time is an intrinsic characteristic of the universe. It does not need to meet any of your criteria to exist. Energy (i.e. the ability to do work) for example, is also an incredibly useful physical quantity that all properties and objects have that is conserved by nature, yet it meets none of your criteria either. A simple way to show that it exists is to ask yourself the following: What would happen if you changed it's properties? You would change the fundamental behavior of the entire universe.