Is time travel impossible because of the conservation of energy law?

[rlortie]

Didn't some one of recognition once make a statement that become a quote.

It went something like; You have all the time their ever was, you have all the time there is, and you have all the time there ever will be.

So the statements "when I get the time or when I have the time, or I do not have the time" are erroneous excuses of something that does not exist.

Ralph

[Jonathan]

I disagree Ken, I think time exists as much as space and matter and energy, that it's linear, and that time travel is impossible. I also think our experience of it is warped by movement, though it doesn't actually change.

[Fletcher]

Interesting thoughts guys. Perhaps I'm being a we bit mundane here. We sort of covered it loosely in an old thread where Mr Tim suggested using an aftermarket device called a "clepsydra".

I tend to think that the conservation of energy laws would cause a major headache for theorists.

I would like it to be possible but the thought comes to mind that if it could be done in the future then shouldn't there be evidence (for those looking) of intervention in our past (assuming the prime directive doesn't apply to all aspects of time travel) & besides who would have policed it, so it should be able to be found ? hmm ... creationist v's interventionists :)

Secondly, ...

EDIT: I have to develop that thought some more. There was an error in my thinking.

[trevie]

We keep saying the time exists, but how do you prove it? by looking at a clock or a watch? Time exists on earth due to the cycle nature of the universe. ie Cyclic rotation of the earth around the sun that gives seasons, and spinning of the earth to give night and day.

By what man has observed, we have established a sense of time and the speed that time travels by the earths seasons and rotation around the sun. If Earth was created on say Mercury then for argument sake, the years would be weeks and weeks would be days and so on and so fourth.

This would construe that time is travelling faster and would we would of evolved to this time thinking.

Everything around us generates and decays at different rates similar to the orbit rates and rotation of the planets in our solar system and is normally compared to our time scale. I guess its bit like using differences in measuring from imperial to metric and vis a versa.

people talk of Dogs having lived 7 years to every one of ours. boy the days must fly.. this is not entirely true, they just age alot quicker and the lifespan is far less than ours.

Going back to the word 'time', its a word that man has created in our own mind to bring order to our lifes and to give sense of direction in the way we set our goals and when I need next to eat and when to harvest our crops etc.

So time is instantaneous you can recall time that happened from billionth of a second ago, to back to our childhood. but we our unable to go forward in time to next week, unless you are unable to perceive passage of time, ie you are in a coma or frozen in a cryo tube similar to fry in the cartoon series known as 'futurama'.

[Joel Wright]

but we our unable to go forward in time to next week, unless you are unable to perceive passage of time

Next week we can all have traveled forward in time 1 week.Hop in the time machine.We arrive in 1 week.:)

[ken_behrendt]

I think that much of our notion that time exists has to do with the human mind's faculties of memory and imagination. Because we can remember a particular situation, we consider it to have some sort of existence in a "past" realm and because we can imagine some sort of situation, we consider it to have some sort of existence in a "future" realm.

But, maybe what we call the "passage" of time is just another way of saying that subatomic particles in the cosmos (and the "higher" assemblies made from them) merely change position with respect to each other. For example, we can define an "hour" as the amount of change in the positions of the subatomic particles of our cosmos that takes place as 1/24 of a rotation of our home planet occurs. This relative comparison can be made without having to use the word "time".

The rotation of the earth, however, is ultimately the end product of the motions of the various subatomic particles from which its atoms are composed. And these subatomic particles can only change position with respect to each other in obeyance of certain fundamental laws of particle physics, most of which we do not yet know. In other words, the motion of these subatomic particles may exist apart from any need to consider the "passage" of time. If that is the case, then, truly, our concept of time would only be an illusion which we maintain because, over the millenia, we in the western world have grown comfortable with it and it makes it easier to talk about the world around us. Eventually, IF time really does not exist, then we will have to develop a new language to describe reality. It won't be easy.

A high school science teacher of mine once told our class that "time is the measurement of motion". He then went on to say that if all motion in the universe stopped, then time itself would stop. This seemed logical to me a the time, but the a priori assumption he made was that motion requires time. What if motion does not require time?

I saw a nice little saying somewhere that said, "Time is the universe's way of keeping everything from happening at once!". Maybe it should have said that time is only the human brain's way of imposing order on certain states of an ever fluxing eternal cosmos?

Oh well, thinking too much about these matters can give one a migraine!

ken

[graham]

This thread really has been quite entertaining and so I feel that I need to cloud the issue even further.

lets say that if there were an empty universe , then for that universe there could be no "time" , just a never ending Present
Now create one grain of sand and place it in that universe . Time now exists in that once empty universe because of that grain of sand.
Not there before but now existing .Time has begun.

Graham

[jim_mich]

There still is no time yet with that one single grain of sand. It takes two grains of sand moving relative to each other before any time can be measured. A single grain of sand has nothing to act as a reference. Time is the reference of movement between two objects. Time is how long it takes for that movement to happen. Without movement there is no time.

Just my opinion.

[Jonathan]

I also disagree with this. I think that in a physical universe, time exists as long as space does too, though without movement there is no way to measure time (or to prove that it is really there). One grain of sand is sufficient to measure time, because it is made up of more than one particle moving relative to another.

[graham]

Johnathan, are you disagreeing with me or with Jim Mich ?.

The way I comprehend this whole mind boggler is that time and mass can only exist together . Time is a consequence of mass.

Without mass there is no time .

But then what do I know ?

Graham

[jim_mich]

And I'm saying without movement of matter there is no time. And without two pieces of matter there is no movement since movement is relative per Mr Einstein. You don't have "space" until you have two peices of matter.

[Jonathan]

I was disagreeing with both of you.
You don't need two pieces of matter for movement, because it isn't relative, you've got the massless aether to measure relative to. I showed the following to my EM teacher a few semesters back, and he saw nothing wrong:
magnetic force w/o relative motion
Of course my opinion on this is subject to change as I learn more.
>You don't have "space" until you have two peices of matter.<
I'm certain that's not true. If it were, then you could have one piece of matter and no space for it to exist in! I say space and time are prerequisites for even a single massless particle.
As a matter of philosophy I think there can be space and time without movement, but I can't prove it.

[rlortie]

You guys are really getting deep into this time thing, so I guess I will add a bit of nonsense on my part.

First the universe is said to be everything, but yet it is expanding, if it is already everything then what is it expanding into. The only thing left would be a dimension of time. From the grain of sand to galaxies, they all create time as they expand.

Ralph

[ME]

It all comes down to reference...

If there is only one thing, it could be all... or nothing, because there is no one to tell (a bit like the Schrodinger cat principle).

If you want to measure a thing, you need space to go around it and space between you and that thing. Because when there is no space, there is no room for movement. When there is space (between two things) you need time to overcome the distance.

[ken_behrendt]

Some interesting ideas here. Everybody seems convinced that without motion there can be no time...that's what my high school teacher kept telling us.

But, when we say something like a certain object is moving at, say, 10 miles per hour, then it's really equivalent to saying that when the object has traveled 10 miles, then one hour of "time" will have "passed". This type of thinking can make one believe that time somehow emerges from measuring motion.

However, we could just as easily have said that when the object has moved a distance of 10 miles, then a point on the earth's equator will have traveled through 1/24 of the circumference of the equator. In other words, we can equate one motion to another and dispense with talking about artificialities like seconds, minutes, hours, days, etc.

If we dispense with the concept of time and embrace the idea of an eternal NOW which is in a constant state of flux and that a parade of "states" present themselves in an order dictated by the laws of physics, then we need some other way of keeping track of the order in which the states appear and of our "separation" from them. The simplest way to do this, without using time language, is to just state how many "standard" units of some cyclic cosmic motion took place between two states of the cosmos or between a particular state and our current state. In the Western world, we have gotten use to using time language for these units, but we should really be using motion language for the units.

Anyway, I do not expect our language to change anytime soon, although the physical concepts are beginning to change.

So...can there be time without motion or, more properly stated, can there be motion without motion? The answer is an obvious "No!". If all motion in the cosmos could be stopped then there would be no way of telling that it stopped because there can be no motion outside of the cosmos which could serve as a reference to determine exactly how much motion did not take place inside of the cosmos! From this it logically follows that, if one has a cosmos, then there must always be motion in it somewhere and it must be eternal and infinite.

ken