The idea of developing a unit of time is no different from making up kilometers to measure distance or grams to measure weight or watts to measure electricity. These are all human constructs that allow us to communicate with each other and to model our world. Time isn’t there until humans decide it is a good way to measure something.
Time is one of the fundamental dimensions of the universe. How we measure it is to some extent arbitrary, but it most certainly exists. It existed for billions of years before we came along to measure it, and it will exist for billions of year after we’re gone.
Time is a concept… a construct we invented to help us quantify things like the movement of the earth around the sun. It’s a convenience that is mathematically sound and helps our modern world function, but as an independent concept, it may or may not be tangible.
There is no need for clocks if time doesnt exist, we make it exsist but, no one decieded what time will come next. Example: 1 Minute could be like an hour and 1 hour could be like 5 seconds. Understand what I’m saying? We don’t even know if there is an hour. I dont know how to explain this.
The only discussion I’ve seen regarding clocks as necessary for the existence of time is in the context of the far-future heat death / end of the universe, when cold particles begin to drift forever apart from one another rendering any kind of physical clock (or observer, for that matter) impossible. Some would argue that under such circumstances time has no meaning (always tough for me to wrap my head around).
Of course ordinary every-day physics, including relativity, is best explained by means of identical frame-localized clocks.
I don’t know… time is real regardless of observation. Entropy was occuring long before anyone was around to measure it. A better way to look at the phrase would be that time is complex, clocks are simple. Time changes based on speed, altitude, etc. and once we start trying to fit that in with our perception of time things get all wonky…
A couple of examples of how time is screwed up.
1.If one twin was on a moving train and the other was on the ground, and the one on the train threw out a baseball then the ball would appear to be moving at very different speeds to both of them.
2. If one twin stayed on earth and the other went off on a rocket ship at close to the speed of light , upon his return to earth the spacetraveller would find his twin to be an old man whereas according to him he was only gone a few days.
“What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know.”
I realize the clocks in this question just metonymize human consciousness; of course time would still exist and be percevied in consciousness even without their existence, just as the concept of length would exist without rulers. In a sense both length and time are measurements (of dimensions) and the units we apply to them meta-measurements.
So @Nullo and @wundayatta are correct re the measurement of time, although I would amend the former’s ‘sequence’ to ‘duration’...
“Instead, let us imagine an infinitely small piece of elastic, contracted, if that were possible, to a mathematical point. Let us draw it out gradually in such a way as to bring out of the point a line which will grow progressively longer. Let us fix our attention not on the line as line, but on the action which traces it. Let us consider that this action, in spite of its duration, is indivisible if one supposes that it goes on without stopping; that, if we intercalate a stop in it, we make two actions of it instead of one and that each of these actions will then be the indivisible of which we speak; that it is not the moving act itself which is never indivisible, but the motionless line it lays down beneath it like a track in space. Let us take our mind off the space subtending the movement and concentrate solely on the movement itself, on the act of tension or extension, in short, on pure mobility. This time we shall have a more exact image of our development in duration.”
Time exists. It is one of the four detectable dimensions in the spacetime of our Universe. It is a baffling one, though. To me, it is by far the most interesting. It runs at different rates for observers in different localized conditions, slowing down in the presence of great mass or as an observer approaches the speed of light.
In Newtonian mechanics and in Relativity, time is bi-directional. By that I mean that if we can fully describe the initial condition, we can project the motion of objects in an orbital system forward or backward with equal accuracy. The same is true in quantum mechanics. Time calculates equally well in either direction. And yet time seems to have a single direction. I can measure either north or south from a starting point, east or west, up or down. But time always seems to advance in only one direction. This effect is called “The Arrow of Time.” But except for the Second Law of Thermodynamics, it is hard to find an arrow of time in physics.
Sorry, I’d like to write a lot more about the subject. It is one of the more awe inspiring aspects of cosmology. But I do have to rush on. I have only so much time to get to all the other great questions here tonight. :-)