What exactly is 'time' ? please define.

[TimberWolf]

I started thinking about "time" as an 'element', as a 'force', as a concept .... what the hell is it exactly !!?!? and where does it come from !!!!?

Newton assumed time was absolute (a big clock that ticks at the same rate for the whole universe), but Einstein tells us that time is relative (your wristwatch won't tick at the same rate or tell the same time for all observers). As a consequence of the postulate that the speed of light being constant for all observers, time and space were connected (into space-time) and in this space events can be agreed by all observers.

I quite like the speculation that time is a statistical process, based on a lot of juju happening outside our familiar dimensions. Anyway, without it we would be in deep tulip, as in not even existing.

[OwlHoot]

Time is a dynamical parameter which allows a Lagrangian to be integrable, which is the case if it admits a foliation.

HTH

[VectraMan]

Time is 10:51, no wait... 10.52.

[scooterscot]

Time is change - think about it.... if movement is not allowed to occur on smallest scale how can time exist?

EO makes a good point about the human perception. Did you know that here in the UK we think of time as in front of us and the past behind us, however in Italy they believe the future is above and the past is below them - don't think about it.

[Ivor Bigun]

Time is 10:51, no wait... 10.52.

Our perception of time, is what time is.
What we see is not real, it is a reflected 2D image.
Our sensation of touch does not make something "real"

We think something is "real" because we see it and touch it at the same time) We, as humans only know "reality" by the instant. Time is the gap between these "realities" and as such is less important.
We stretch and slow down our perception of time constantly yet we are not normally aware of it.

Consider yourself, waiting for the phone to be answered, the phone is ringing "Durr Durr" etc
Take the phone away from your ear for a short while, then put it back to your ear. On a few occasions, you will be suprised how long the silence is - It will appear longer until you hear it eventually ring.
After you've heard it, the silence gaps appear to be normal.

What is happening?
When you hear something rythmic, part of your "flight or fight" brain shuts off.
The brain "knows" that there will be a ring so it goes into your normal "concious" thinking which is quite deliberate (multitasking if you like) - rather like holding an image in your head as opposed to being "blank" .

When you take your ear away from the telephone and put it back, that part of the concious brain is "reset to blank" and the instant you put the telephone to your ear, you start hearing the rings with the raw "fight or flight" part of your brain (your subconcious/instinct) This is faster i.e. time appears slower. That is why it appears that the silence gap is longer. You may even feel a slight "fear" before you hear the eventual ring. When your brain has established the pattern, you no longer feel that fear.

[AlfredJPruffock]

Time is - not what you think it is.

[Ivor Bigun]

Our perception of time, is what time is.
When you hear something rythmic, part of your "flight or fight" brain shuts off.
The brain "knows" that there will be a ring so it goes into your normal "concious" thinking which is quite deliberate (multitasking if you like) - rather like holding an image in your head as opposed to being "blank" .

What I should have added - is that when you are "enjoying" yourself, time passes quickly. Why? because whatever you are enjoying is tripping your brain into a concious "steady state" - similar to being asleep.
The most powerful "time slip" device your brain has, is of course when you are asleep.

When you are bored, you are thinking more with your "flight or fight" part of your brain - almost constantly - this is very expensive in terms of "alertness" and can give rise to feeling blue as sugars drop. Its Nature's way of slowing you down to give your body a rest.

[EternalOptimist]

Ivor

you are concentrating on the human psychological awareness of time. If you think about time, it passes slowly. A watched pot never boils.

Have you ever gotten into your car for a long journey, then stepped out and thought, 'that went fast'. Other times it can seem like an eternity.

but time passes for cats and dogs. and daffodils.

[Liability]

time is simply a timer as to how long you have left to die.

[NotAllThere]

It is incorrect to say that there was time before the big bang, because it didn't have a cause. Time came into existence at the time of the big bang. That was settled by Augustine.

Time is merely distance travelled in at right angles to the three dimensional space we think we live in. One second is 186 million metres.