Thought - time travel

[jake williams]

Isn't everything in the universe (well, basically everything, at least) moving forward in time constantly and simultaneously? So all this talk about "what if I went back in time and killed myself"... if you went back in time, wouldn't the universe be empty at every point that isn't the present?

[ÑóẊîöʼn]

Isn't everything in the universe (well, basically everything, at least) moving forward in time constantly and simultaneously?

No, as that assumes a universal frame of reference, something that Relativity forbids. Objects travelling close to the speed of light experience time dilation, going further forward in time than slower objects.


So all this talk about "what if I went back in time and killed myself"... if you went back in time, wouldn't the universe be empty at every point that isn't the present?

That rather depends. The temporal dimension could simply be the subjective movement through a series of still "frames" of the universe - every "moment" would exist as a still frame, and time is simply movement through those frames.

Or it could be something else. Our understanding of time is surprisingly limited.

[jake williams]

No, as that assumes a universal frame of reference, something that Relativity forbids. Objects travelling close to the speed of light experience time dilation, going further forward in time than slower objects.
The proof for this is sort of awkward, like you said, our understanding of time is pretty limited. Obviously something like this is going to be an issue, but my understanding is that for most matter in the universe, time dilation is an extremely minor occurrence?



That rather depends. The temporal dimension could simply be the subjective movement through a series of still "frames" of the universe - every "moment" would exist as a still frame, and time is simply movement through those frames.
This idea doesn't make any sense to me. If everything in the universe exists at every moment, what exactly is moving "through" it?

[ÑóẊîöʼn]

The proof for this is sort of awkward, like you said, our understanding of time is pretty limited. Obviously something like this is going to be an issue, but my understanding is that for most matter in the universe, time dilation is an extremely minor occurrence?

The point is that it happens. Since there is no absolute frame of reference, things going on in one star system don't necessarily happen "in synch" with things going on in another star system light years away. It's something to do with the speed of light and the fact that it is finite.

Apparantly it's not just physical objects that cannot achieve lightspeed or faster, but also information cannot be transmitted faster than light - I forget the exact reason why - I think it has something to do with causality.


This idea doesn't make any sense to me. If everything in the universe exists at every moment, what exactly is moving "through" it?

Who says that anything has to "move" through the frames? The frames could be instants of the smallest possible amount of time, and the time-frames propagate as a product of the Big Bang*, much in the same way that universal spatial expansion is a product of the initial singularity. The propagation provides the "passing" of time, with the increasing amount of time being analagous to the increasing amount of space in the universe.

In other words, space expands without anything needing to actually move, and time passes without the need of anything to "travel" through time.

Hopefully I made sense.

*(and if parallel timelines are proven to exist, the series of time-frames could split as different possibilities occur)

[AGITprop]

All this talk of time travel! We can travel in time comrades, but only in one direction and that is forward. Time is only defined by the motion of matter and energy. Without motion, there is no time to speak of. You cannot play the universe in reverse. Particles move, therefore time is passing by. Time travel into the past is just sci-fi BS.

[ÑóẊîöʼn]

All this talk of time travel! We can travel in time comrades, but only in one direction and that is forward.

Until we actually attempt to build a time machine, and until we actually flip the switch on said time machine, we cannot say that we are limited to travelling only forwards in time.


Time is only defined by the motion of matter and energy.

Wrong. Time passes no matter what velocity matter moves, and time passes regardless of whether energy exchange is occurring or not.


Without motion, there is no time to speak of.

That's not a falsifiable hypothesis, as nothing is truly "motionless".


You cannot play the universe in reverse.

And I can't spin the Moon on my fingertip. What's your point? Time travel is not necessarily about "rewinding the universe".


Particles move, therefore time is passing by.

What next, Cpt Obvious?


Time travel into the past is just sci-fi BS.

Again, without a working example of a time machine, that cannot be said with any certainty. Their is no evidence of time travel, but that does not necessarily rule it out.

[FireFry]

Time in fact is a fluke of the universe. It is created by motion and gravity. I forget the actual physical mechanics of it, but I remember something like, matter x c^2 is energy and that all matter is just energy with attractive gravitational forces to each other.

It's complicated, and hard to understand at the present moment, but eventually we'll straighten out our understanding of the basic physical universe.

[AGITprop]

Until we actually attempt to build a time machine, and until we actually flip the switch on said time machine, we cannot say that we are limited to travelling only forwards in time.



Wrong. Time passes no matter what velocity matter moves, and time passes regardless of whether energy exchange is occurring or not.



That's not a falsifiable hypothesis, as nothing is truly "motionless".



And I can't spin the Moon on my fingertip. What's your point? Time travel is not necessarily about "rewinding the universe".



What next, Cpt Obvious?



Again, without a working example of a time machine, that cannot be said with any certainty. Their is no evidence of time travel, but that does not necessarily rule it out.

Then what do you define as time. What time is a a system of measurement that we have concocted to measure the motion of matterby comparing it to the motion of other matter. ie; the revolutions of the earth around the sun, the earth spinnig on its axis. time is not a thing that can e independant of motion. this idea of a time machine is ridiculous. You are right, nothing is motionless and cannot be motionless, therefore time cannot stop or go in reverse. If you take an atom and throw it 100 yards. then make it do the reverse, it is not traveling back in time, only forward in another direction.

[ÑóẊîöʼn]

Then what do you define as time.

I use the physicist's definition.


What time is a a system of measurement that we have concocted to measure the motion of matter or just life by comparing it to the motion of other matter.

Time existed before human beings. It is more than a "system of measurement".


ie; the revolutions of the earth around the sun, the earth spinnig on its axis. time is not a thing that can e independant of motion.

You say this, but you provide no evidence. Time passes no matter what an object's velocity is, therefore one can only conclude that time is independant of motion.


You are right, nothing is motionless and cannot be motionless, therefore time cannot.

But since nothing can be motionless, you cannot prove your hypothesis by making something like a chronometer absolutely still. You cannot prove your alleged link between time and motion. Hence, your time-motion hypothesis is not falsifiable.


If you take an atom and throw it 100 yards. then make it do the reverse, it is not traveling back in time, only forward in another direction.

That only serves to prove that time is independant of motion - time goes forward no matter what direction the atom travels in.

[jake williams]

It's complicated, and hard to understand at the present moment, but eventually we'll straighten out our understanding of the basic physical universe.
There's no real valid reason to suspect the universe is comprehensible by humans. In fact, the "better" our science gets, the clearer the possibility that the universe is totally beyond our understanding gets - and I don't mean sort of this "It's weird and complicated, but we know what's going on" - we literally just have no fucking clue. Doesn't mean we don't try. We have some good ideas, and the successes of science in the last few centuries are mind-blowing, almost as incomprehensible as the universe we're studying itself.

[AGITprop]

Time existed before human beings. It is more than a "system of measurement".
Understood. We give time a scale for our own purposes. But again, time is only defined by the motion of matter.



You say this, but you provide no evidence. Time passes no matter what an object's velocity is, therefore one can only conclude that time is independant of motion.
No, because if there was no motion, what time would there be to measure.



But since nothing can be motionless, you cannot prove your hypothesis by making something like a chronometer absolutely still. You cannot prove your alleged link between time and motion. Hence, your time-motion hypothesis is not falsifiable.
Again, time and motion cannot exist independantly of each other. Time is nothing without motion and motion takes place in time.



That only serves to prove that time is independant of motion - time goes forward no matter what direction the atom travels in.
Yes, bcause the atom is moving. If the atom stps moving, which it cannot, time has stopped, which it canot, assuming that atom was trhe only perticle in the universe. But this aplies to all matter.

Geez, i should realy learn how to repost quotes.....^^^^^^^^^

[ÑóẊîöʼn]

Yes, bcause the atom is moving. If the atom stps moving, which it cannot, time has stopped, which it canot, assuming that atom was trhe only perticle in the universe. But this aplies to all matter.

You still need to prove that motion and the passage of time have a 1:1 relationship.

[AGITprop]

You still need to prove that motion and the passage of time have a 1:1 relationship.
The reality is that time does not exist independently, time is just the state of existence of matter. If there is no matter there is no time.
This is an intellectual flaw; the idea that time is something we exist in and is something we can buy a ticket to travel back in.

[AGITprop]

Anyone else wish to add to this conversation?

[ÑóẊîöʼn]

The reality is that time does not exist independently, time is just the state of existence of matter.

Again, you need to provide some evidence to support your assertions, rather than just expecting us to accept them at face value.


If there is no matter there is no time.

That means that time does not pass in a vacuum, which is clearly nonsense. According to Einstein, it is space and time which are closely correlated, not matter and time.


This is an intellectual flaw; the idea that time is something we exist in and is something we can buy a ticket to travel back in.

It's not an "intellectual flaw", it is a hypothesis that requires more evidence. To baldly state that time travel is impossible is not falsifiable and hence unscientific.