# What is time?

Discussion in 'Physics & Math' started by MikeD22, Jun 21, 2002.

1. ### Merlijncurious catRegistered Senior Member

Messages:
1,014
degrees of freedom is a term describing on how many ways the state of a system can be realised. Hmm maybe this is still quite vague.
When you read any book by Ian Stewart (e.g. "Life's other secret", a very good book!) you will get to understand what I mean. You do not need special training in mathematics to read them.

3. ### FrencheneeszAmazing MemberRegistered Senior Member

Messages:
739
Hmm, im sure if its so easy you can explain it here. Water to gas.... i can't see any difference in the ways it can be "realized" how many are there usually?

how many degrees of freedom are in a watch, or a car? Is this "degrees of freedom" stuff scientific?

It DOES seem vauge, but i don't exactly want to buy a book to try to understand it.

5. ### Merlijncurious catRegistered Senior Member

Messages:
1,014
Frencheneesz,
Degrees of freedom is most often used in statistics. In mathematics or physics, it resembles the term entropy.
Mathworld (http://mathworld.wolfram.com) gives this definition
"The number of degrees of freedom in a problem, distribution, etc., is the number of parameters which may be independently varied. "

7. ### FrencheneeszAmazing MemberRegistered Senior Member

Messages:
739
According to the link you gave me and other sites i looked up, degrees of freedom are purely mathematic. In phisics it is the number of ways of describing something, like measuring the pressure, temperature, size, motion, and anything else you can think of.

The universe does not have some sort of conspiracy for it to be mathmatically easy to anylize. The number of parameters is on the fringe of opinion, because you could say color and what light bounces off of it, is absorped by it, and what wavelengths an object is transparent to are either different parameters or interchangable parameters.

there are almost infinite number of ways an object can be described, and there can be no rule that the universe gets progressively less parameters.

You never answered my question about how you can measure the number of parameters an object, like a car, has. So, how do you measure that?

8. ### Merlijncurious catRegistered Senior Member

Messages:
1,014
the number is astronomical (just like in CUBE)

And I am not even interested in doing so. I just gave a measure for ordering. You told us that ordering is a purely subjective measure. I told you that you were wrong (in my opinion). I feel in no way obliged to actually do the measuring/calculating.

9. ### StormcrowRegistered Member

Messages:
2
In regards to time, here is what I think. Imagine your three dimensional space. Place a bubble over top of it. The origin is the beginning of the universe, the x,y,x coordinates are the locations of events, and the bubble is the time we currently exist in which is always exanding as time progresses. Does this make sense to anyone?

THX
°Stormcrow°

10. ### le coqRegistered Senior Member

Messages:
75
What makes it true, as true as something can get that is defined rigorously with mathematics, is that the main descriptors of physical phenomenon other than mass involve space and time. Speed, acceleration, energy, work, momentum, power, all have time in the equation. Without time there is no energy, and no observable universe.

Le Coq

11. ### FrencheneeszAmazing MemberRegistered Senior Member

Messages:
739
"Without time there is no energy, and no observable universe."

Did I say time didn't exist?!

12. ### Merlijncurious catRegistered Senior Member

Messages:
1,014
Welcome Stormcrow,
I can't quite follow what you mean with the analogy....could you elaborate more?
e.g. why is the bubble not party of the 3-d space it envelopes? or did I not understand it at all?

bye,
Merlijn

13. ### On Radioactive Waveslost in the continuumRegistered Senior Member

Messages:
985
i think Stormcrow was saying that we must describe our observable universe in four dimensions, x,y,z and t so this would mean parrametric equations right?

14. ### StormcrowRegistered Member

Messages:
2
Yes Yes,
X,Y, and Z are spatial coordinates and t is our temporal position. The orgin of x,y,z, and t would be the creation of the physical/ temporal universe (Big Bang or God). As the universe expands the t-sphere expands around the equally expanding xyz system. If you can imagine this you can say mathematically where and when an event has occured. Also it would suggest that time travel to the past is possible, but not into the future where xyz,t have not existed yet.

Any clearer?

°Stormcrow°

15. ### On Radioactive Waveslost in the continuumRegistered Senior Member

Messages:
985
there is a good book that explains this stuff in only about 100 pages and it covers very diverse topics about life and our existance the way we know it

it called : "stalking the wild pendulum"