What is time

[Tugrul]

:confused:Some say time is the movement of earth around the sun and the earths axis.

Some believe in the space-time continuum.

Others believe in different things.

 

What about ageing of matter or shall i say existance of matter and the laws of physics. Could that be time? Here is an example if all forces and matter stoped to interact and spin would time carry on?

 

Please state yours vieves upon this subject

 

(i am aware of the laser experiments involving the sun and all that)

[ajb]

What is time falls outside the realms of physics. What physics can do is give you mathematical models that describe time. The best I can really do is direct you towards general relativity.

 

I am sure no-one here will give you a very satisfactory explanation of what time is.

[swansont]

Time is what is measured by a clock. What a clock measures is the phase of an oscillation.

 

 

Ad ajb has already noted, the above is a mathematical description. What you are asking is metaphysics.

 

Here is an example if all forces and matter stoped to interact and spin would time carry on?

 

Case in point. When your scenario requires exploring results of physically impossible scenarios, the odds are pretty good you've left the realm of science discussion.

[SH3RL0CK]

Time is (http://dictionary.reference.com/browse/time)

the system of those sequential relations that any event has to any other, as past, present, or future; indefinite and continuous duration regarded as that in which events succeed one another.

Or in my own words, some kind of observable change in something.

 

When your scenario requires exploring results of physically impossible scenarios, the odds are pretty good you've left the realm of science discussion.

 

But heat death of the universe ( http://en.wikipedia.org/wiki/Heat_death_of_the_universe ) might not be physically impossible. In fact, it might be inevitable. Granted the time scales become truely immense before this would happen.

 

Although this seems a moot point as, if this is the case it is impossible that we would still be around, I would say the whole concept of time would then become meaningless as change no longer is possible.

[swansont]

Time is

But heat death of the universe ( http://en.wikipedia.org/wiki/Heat_death_of_the_universe ) might not be physically impossible. In fact, it might be inevitable. Granted the time scales become truely immense before this would happen.

 

Although this seems a moot point as, if this is the case it is impossible that we would still be around, I would say the whole concept of time would then become meaningless as change no longer is possible.

 

Heat death is not the same as all interactions stopping.

[SH3RL0CK]

Heat death is not the same as all interactions stopping.

 

I had kind of thought all interactions stopped as the entropy winds down, but thank you for telling me otherwise. Is it that the interactions simply take an ever-increasing amount of time (i.e. the limit is approached by never actually reached in a finite amount of time)?

[david23]

Time is a man made concept there is only space and distance,time would be a division of distance.

if you run a mile in four minutes, man made again

if you traveled two light years away and came back that would be 4 light years,if it only took you a minute from the viewers point of view and yours, then all that distance in 1 minute, they would only be 1 minute older also

186k miles per second mathematically add a zero, 10 times the speed of light

mathematically possible

when I was a small boy I asked my father how long will it take to get to where he was driving, his answer was about five cigarettes

[ajb]

Time is a man made concept...

 

Isn't every concept a man made one?

[Mr Skeptic]

Here is an example if all forces and matter stoped to interact and spin would time carry on?

 

All your clocks would stop, if that's what you mean.

[swansont]

I had kind of thought all interactions stopped as the entropy winds down, but thank you for telling me otherwise. Is it that the interactions simply take an ever-increasing amount of time (i.e. the limit is approached by never actually reached in a finite amount of time)?

 

An interaction becoming small because of its natural behavior, e.g. r gets large for a 1/r^2 interaction, is something that can be described with science. But simply ignoring the term when it isn't small — turning it off — is not.

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Merged post follows:

Consecutive posts merged

Isn't every concept a man made one?

 

Quite so. I find the concepts of energy and momentum quite useful as well. Charge, entropy, magnetic fields … physics is chock full of useful man-made concepts.

Edited November 11, 2009 by swansont
Consecutive posts merged.

[liarliarpof]

(True Story) A respected physicist visited the 'Master Timekeepers' (Burrowed into a mountain near Denver, I believe.) While touring, the physicist said, "So this is the apex of time measurement?". His host replied, "No, This is where we make precise measurements of something, convey the results to scientific community, which they then refer to as 'time'.

[swansont]

(True Story) A respected physicist visited the 'Master Timekeepers' (Burrowed into a mountain near Denver, I believe.) While touring, the physicist said, "So this is the apex of time measurement?". His host replied, "No, This is where we make precise measurements of something, convey the results to scientific community, which they then refer to as 'time'.

 

Near Denver? BLASPHEMY!

 

The master timekeepers are on a hill in Washington, DC.

 

There are some other people who happen to measure time in Boulder, CO, but they are not buried in a mountain. (They are very good at what they do, though)

 

The quote is pretty good, though.

[Phi for All]

The folks at Cheyenne Mountain (near Colorado Springs, not Denver) don't care about time. They have all the time in the world.

Edited November 12, 2009 by Phi for All

[radienx000]

i think that what your saying is that time is independent, and it is seen to have a "self".

[devrimci_kürt]

I wonder if time ends, what happens afterward?

[Sisyphus]

I wonder if time ends, what happens afterward?

 

If there's an "afterward," then time hasn't ended, has it?

[devrimci_kürt]

in short, time hasn't ended....

right?

[Sisyphus]

in short, time hasn't ended....

right?

 

...right?

[devrimci_kürt]

that is, then(In this case ) time will never end..

Do you agree with me about this?

[Sisyphus]

that is, then(In this case ) time will never end..

Do you agree with me about this?

 

No, I don't agree. At least, I don't think that conclusion follows. It's just circular reasoning. There's an after, therefore time hasn't ended, therefore there's an after....

[yasir]

is there anyone who can explain me what is time?

[Phi for All]

is there anyone who can explain me what is time?

Did you get a chance to read the explanations before your post?

[jajrussel]

Time is the relationship between two events.

All you have to do is define the relationship to give it meaning. However, the relationship exist whether you define it, or not. The more accurately you define it, the better you will understand it. You don't have to describe it, or define it to experience it. You don't have to experience it to define, or describe it. You can guess. Which, means you can define it any way you want to. How accurately, your description, is entirely up to you. The accuracy of all relationships depends on the complexity of the definitions, and definitions are basically answers to questions. You can make the answers to the questions simple to achieve by throwing out any parts of the relationship that are hard to define, but then you have to be willing to accept that the answer might not be clearly defined. If you are willing to accept an answer that isn't clearly defined, you might as well ask someone else the question, because any answer they give you will lack clarity, or be too complex to be clear. Possibly, even wrong.

[ajb]

Time is the relationship between two events.

All you have to do is define the relationship to give it meaning. However, the relationship exist whether you define it, or not. The more accurately you define it, the better you will understand it.

 

It sounds like you are trying to describe a causal structure on space-time or a causal relation between points on space-time.

 

This is part of general relativity.

 

See Hawking and Ellis, The Large Scale Structure of Spacetime, Cambridge University Press 1973

 

or just the wikipedia article to start.

[jajrussel]

Sort of, kind of, maybe? Not really! Often my attempts at humor are somewhat vague. I had never heard of a Lorentzian manifold, or causal relations between points in the manifold until you directed me in that direction. I view time as a tool, and like any tool it sometimes has to be reshaped in order to work. Often, time becomes a part of the problem we are trying to solve, and we can not see any way to remove it from the problem, so it becomes an associate of the problem. Regardless, how we associate time though, time has no effect on what is happening. The effect is a result of a cause, and the distance between the cause and effect would exist even had we not invented tools for measuring that distance. We could say that something might not have occurred, had not something else occurred for the length of time that it did, but we could also say that what originally occurred had no choice but to occur the way it occurred, effectively linking causes and effects without a time reference. Then someone else will come along and say that regardless the lack of time reference, time still exist. I can not argue with that, because if I want to understand either of the events one of the tools I am going to have to use is time.

I do tend to have trouble accepting the idea of time travel. There is nothing wrong with hoping that there might be ways to time travel. The thought probably entered peoples minds long before anyone thought to link space and time mathematically, but before they start building their time machine they might want to try something easier first, like physically drawing a square using time coordinates for the corners.

What is time, is not an original question. I am not even sure of how old the question really is. For a very long time people a lot smarter than I am, have been figuring out ways to use it. Today, people are using time in ways I can hardly comprehend. For that reason alone I'm not qualified to answer the question, but I can guess, and my simplest guess would be that time is a tool.