Why is time special?

Souron said:
Not quite. Absolute zero is what it is: No motion or energy in the system.

Quantum macanics simply mandates that no point in space can be at absolute zero. The uncertainty principle prevents it.*

*though not in the way you might think.
And yet another. Help me out here guys, what is correct (for now anyway)?
 
warpus said:
I'm talking about the equations we've devised to model the Universe with. They work incredibly well - implying that they must be good approximations of reality. Time is a variable in all of these equations. If we extrapolate from the equations it is implied that time is an actual dimension and not just something we invented to measure the passage of .. time with.
First you extrapolate, then you infer to determine that time is an actual dimension and not something invented. That is an interesting process. :mischief:
 
Birdjaguar said:
First you extrapolate, then you infer to determine that time is an actual dimension and not something invented. That is an interesting process. :mischief:

Does it seem a little bit circular? Well, I guess it is - a bit.

But the point is that the equations do a really good job of modelling the universe - and they would never work if you took out time as a variable. So unless we're presented with a brand new set of equations that do a better job and don't have time as a variable - I'd say we're forced to concede that to the best of our knowledge - time is a dimension.
 
Time can only be defined according to movement.
Movement can only be defined according to time.

It's always funny when you find redundant definitions such as those. For any rational mind, this is disturbing and sound incomplete. It's always funny to find those examples of very simple things which are quickly assimilated by our human minds but turns out very hard to define. :)
 
Well if you want a definition of time here's the thermodynamic definition:

A time demetion is any demention such that the enthropy along the demention consistantly increases in one direction. "Time" is the only existing time demention.
 
Souron said:
Well if you want a definition of time here's the thermodynamic definition:

A time demetion is any demention such that the enthropy along the demention consistantly increases in one direction. "Time" is the only existing time demention.
An increase is a movement. ;)
 
warpus said:
Does it seem a little bit circular? Well, I guess it is - a bit.

But the point is that the equations do a really good job of modelling the universe - and they would never work if you took out time as a variable. So unless we're presented with a brand new set of equations that do a better job and don't have time as a variable - I'd say we're forced to concede that to the best of our knowledge - time is a dimension.
I don't know if it is circular; I'll leave that to others to figure out. It seems very subjective (extrapolate, infer, claim as actual). Just because time works in math equations as a variable, doesn't mean much. Inches, miles and meters also work well in math. They are only conventions of convenience and tradition into which we have vested significance. Time as a variable is much the same. What is it about time's role in mathematics that warrants it being called a dimension? In some ways the question can be boiled down to "Is time a cause or an effect?" I am in the camp that says it is an "effect" and you are making the case for it being a "cause". I think my case is easier. ;)

Of course, that leaves me with "change" as a "cause". Or "movement" to pick up on Marla's comment. My only real support for "change" as a fundamental force in the universe is that "change" seems to actually be present all the time at every level of matter. And in my mind it follows that change creates time.

Could time be separate from change? Or are "time" and "change" the same, as Marla posted? Are they flip sides of the same "coin"?
 
Birdjaguar said:
And in my mind it follows that change creates time.
To me it seems like time allows change to happen, not the other way around. Like how air allows us to breathe, but our breathing doesnt create the air.
 
Birdjaguar said:
My only real support for "change" as a fundamental force in the universe is that "change" seems to actually be present all the time at every level of matter. And in my mind it follows that change creates time.

I disagree - because change still occurs while time stays still.

From the point of view of a photon - time is still... yet there is change, due to quantum fluctuations.. If change indeed created time - this would be impossible - but it happens.

bozo erectus said:
Doesnt it take time for space to inflate?

Perhaps, but if there was no space to begin with then it could not inflate.
 
Im no physicist by any stretch of the imagination, it just seems logical that space happens within time. Space needs Time, but what does Time need?
 
Birdjaguar said:
Just because time works in math equations as a variable, doesn't mean much. Inches, miles and meters also work well in math. They are only conventions of convenience and tradition into which we have vested significance.

?? Inches, miles and meters are perfectly legitimate measures of real spatial dimensions, too. A certain prehistoric beetle really was 25 mm long and 0.98 inches long even before anyone was around to invent those measuring units. Where's the problem?
 
Bozo Erectus said:
Im no physicist by any stretch of the imagination, it just seems logical that space happens within time. Space needs Time, but what does Time need?

I'm still not convinced that space needs time!
 
warpus said:
I'm still not convinced that space needs time!
Well, everybody seems to be agreed that without Time, there would be no change, right? The 'inflating' of Space or whatever its called, would involve change wouldnt it? So how could the Space side of the equation happen if Time wasnt already up and running?
 
Ayatollah So said:
?? Inches, miles and meters are perfectly legitimate measures of real spatial dimensions, too. A certain prehistoric beetle really was 25 mm long and 0.98 inches long even before anyone was around to invent those measuring units. Where's the problem?
There is no problem for me. I think time is just a unit of measure that we use to track change like we use meters to measure the distance between points in space.
 
Bozo Erectus said:
Well, everybody seems to be agreed that without Time, there would be no change, right? The 'inflating' of Space or whatever its called, would involve change wouldnt it? So how could the Space side of the equation happen if Time wasnt already up and running?
No. Without change there would be no time. At the very first instance of change in the fabric of existence that very quickly become the big bang, time began. Time could not exist prior to some tiny first change. How can time exist where there is no change?
 
Birdjaguar said:
No. Without change there would be no time. At the very first instance of change in the fabric of existence that very quickly become the big bang, time began. Time could not exist prior to some tiny first change. How can time exist where there is no change?
We're in sort of a chicken or egg debate. If I understand what youre saying, things change, and thats what Time is, snapshots of different states. I dont necessarily dissagree with that, except that to me, it seems like Time needs to exist for their to be change in the physical universe. The reason that we all grow old is that linear time exists. Linear time doesnt exist because we grow old, IMO.
 
warpus said:
I disagree - because change still occurs while time stays still.
Can you give me a non mathematical example of this?
warpus said:
From the point of view of a photon - time is still... yet there is change, due to quantum fluctuations.. If change indeed created time - this would be impossible - but it happens.
If there are quantum fluctuations, then there is change. Quantum state 1 becomes quantum state 2. Perhaps our yardstick is not up to the task of measuring such evetns? Now if those two states exists simultaneously for the photon, then the fluctuation does not really exist, but a single state that is neither 1 or 2 does. If it is a question of probabilities, then I would say that we do not yet have the tools to measure accurately enough to separate the different states.
 
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