Absolute Time, I know its wrong and all but tell me if I got it right

[Rishabh Narula]

please tell me if I'm correctly understanding what Newton was trying to say about
time being absolute.did he mean that it doesn't matter whether or not you have
a clock(which could be any repetetive phenomena)
or how that clock is moving,
time exists independently of all observation.(that's how I am interpreting
what he said)
that is even if there was'nt any clock(repetetive phenomena) time is still
passing...its just that we can't observe it.
of course i am aware that this whole thing about absolute time is incorrect and was
corrected in theory of relativity,
could it also be that saying time exists without observation is because in our
brains chemical or electrical processes are always changing giving us thoughts
and a sesnse of time passing.i.e that our brains are also kind of clocks.
and thus even in empty space its just our brains giving us a notion of time
passing.time doesn't exist in empty space,since nothing is changing and change is time.
Am I grasping it right?if not,correct me anyways.:3
the para I am reffering to- from a book on mechanics

Absolute, true and mathematical time, of itself and by its own
true nature, flows uniformly on, without regard to anything external. Relative, apparent and common time is some sensible and external measure
of absolute time estimated by the motions of bodies, whether accurate or
inequable, and is commonly employed in place of true time; as an hour,
a day, a month, a year.
Mach commented “it would appear as though Newton in the remarks
cited here still stood under the influence of medieval philosophy, as
though he had grown unfaithful to his resolve to investigate only actual
facts.” Mach went on to point out that since time is necessarily measured by the repetitive motion of some physical system, for instance
the pendulum of a clock or the revolution of the Earth about the Sun,
then the properties of time must be connected with the laws that describe the motions of physical systems. Simply put, Newton’s idea of
time without clocks is metaphysical; to understand the properties of time
we must observe the properties of clocks.

 

[Ibix]

Practically, what absolute time means is that two ideal clocks, once synchronised, will never go out of sync. In practice, of course, clocks don't tick at the same rate due to mechanical issues of one sort or another. I think Newton is attempting to duck the issue of which clock (of the five we've got on a desk which all show slightly different times) is right by appealing to an imaginary ideal time that Is Right.

Quite apart from the complexities of time in relativity, Einstein simply doesn't care about things he can't know. He says "time is what clocks measure" and takes no position on any deep philosophical questions on the nature of time. There are some clocks that repeatably show the same time once zeroed, while others drift even if well treated. We take the first kind to be accurate clocks.

 

[anorlunda]

I think Newton is attempting to duck the issue of which clock (of the five we've got on a desk which all show slightly different times) is right by appealing to an imaginary ideal time that Is Right.

That reminds me of a saying I haven't heard for some time. "A man with a watch always knows what time it is. A man with two watches never knows what time it is."

 

[PeroK]

That reminds me of a saying I haven't heard for some time. "A man with a watch always knows what time it is. A man with two watches never knows what time it is."

What about a man with a watch and a cell phone?

 

[Ibix]

A man with two watches never knows what time it is.

Well, the watch on my phone updates itself from Greenwich, so I trust that.

Although we had mechanical clocks at work that updated themselves from Greenwich. One was twenty minutes slow, precise to the nearest nanosecond, because the hands had somehow been mounted incorrectly. A colleague set it correctly one day, not knowing what type of clock it was. The look on his face when it whirred through eleven hours and forty minutes to reset itself to the same wrong time was priceless.

 

[julcab12]

According to this guy. No 2 clocks are the same.
"Time is nothing more than motion and the motion of all matter in the universe is affected by the environment.

We do not have devices that measure time. Do you think your watch “measures time”? Think hard. Got it? You are right, it does not measure time, it measures motion.

Now, all devices that measure motion are affected by their environment, take a grandfather clock and put it into -60C weather, do you think it will keep the same motion as the one in +20C? Take an hourglass into orbit, will the sand fall at the same rate as the one on the ground? Take an atomic clock up into the sky, do you think the Cesium 133 atom will vibrate at the same 9,192,631,770 vibrations per second? Take GPS satellites and zip them around the earth, do you think the clocks on them will keep the same time?

Even two atomic clocks that are sitting right next to each other will not experience exactly the same motion, there will be differences in them that are so minute that they are beyond our capability to measure but say you allowed the two side by side Atomic clocks hundreds of years to sit side by side, the slight differences in the motions would aggregate into something measurable at some point. Their environments are extremely close, but not exactly the same."

 

[anorlunda]

What about a man with a watch and a cell phone?

Uh oh, I'm dating myself. That expression comes from the era when all watches were mechanical.

Even the earliest digital watches had accuracy problems. I remember the approximate rule, 1 minute per day error typical for mechanical watches and one second per day for digital watches.

I remember how happy I was when I got a solar powered watch that synchronized itself with Fort Collins Colorado. I used to take it off when I slept and left it above deck pointing in the direction of Mecca Fort Collins. I never found out if it would continue working if I circumnavigated.

 

[Ibix]

According to this guy. No 2 clocks are the same.

He doesn't seem to be saying anything radically different from Einstein's "time is what clocks measure", just in rather more words. And he seems to regard motion (normally regarded as change of position over time) as fundamental and time as derived rather than vice versa. I don't see that as particularly helpful, but maybe it is for Rovelli.

 

[phinds]

What about a man with a watch and a cell phone?

He wouldn't CARE what time it is 'cause he'd be busy on his cell phone.

 

[julcab12]

He doesn't seem to be saying anything radically different from Einstein's "time is what clocks measure", just in rather more words. And he seems to regard motion (normally regarded as change of position over time) as fundamental and time as derived rather than vice versa. I don't see that as particularly helpful, but maybe it is for Rovelli.

That is exactly the reason why he came up with relational aspect of physics and such. He describes the relative evolution of physical variables rather than their evolution in time like the usual.
"There isn’t a single notion of time that is either true or false. What we call time is a rich, stratified concept; it has many layers. Some of time’s layers apply only at limited scales within limited domains.

For instance, the distinction between up and down is not an illusion, but it has no meaning away from Earth. There is no up and down for astronauts during interplanetary travel. Many properties of time are similar. In particular, there are aspects of our own human experience of time that are very much tied to the specific way our brain works: the fact that we have memories, that we anticipate the future, and so on. It is the human brain, not fundamental physics, that determines what we call the flowing of time and the sense of the speed at which it flows."

This is not particularly mainstream and will stop here. Ill leave that to him.