Without time.

[StringJunky]

Clocks go to better than a part in 10^15. There's seemingly always someone who wants a better standard, or finds a use for one. Form mass I'm not sure what the application is, but I assume it's out there.

I read recently the possible accuracy of the latest clocks will allow altimeters of 1cm accuracy to be made. I could be wrong, but I think it's at 20cm at the moment. Even at 20cm increments, I think that's a stunning vindication of Relativity.

 

Edit: Found the article. I was a bit off with the accuracy: 2cm

 

The JILA clock is now good enough to measure tiny changes in the passage of time and the force of gravity at slightly different heights. Einstein predicted these effects in his theories of relativity, which mean, among other things, that clocks tick faster at higher elevations. Many scientists have demonstrated this, but with less sensitive techniques.

"Our performance means that we can measure the gravitational shift when you raise the clock just 2 centimeters on the Earth's surface," JILA/NIST Fellow Jun Ye says. "I think we are getting really close to being useful for relativistic geodesy."

 

 

Read more at: http://phys.org/news/2015-04-atomic-clock-accuracy.html#jCp

Edited May 11, 2015 by StringJunky

[swansont]

I read recently the possible accuracy of the latest clocks will allow altimeters of 1cm accuracy to be made. I could be wrong, but I think it's at 20cm at the moment. Even at 20cm increments, I think that's a stunning vindication of Relativity.

 

Edit: Found the article. I was a bit off with the accuracy: 2cm

 

 

The current level of precision raises the question of "where are the atoms"?. If the lattice gives you a cloud of atoms 1 cm in diameter, then that will limit the precision; the clocks at the top tick at a different rate than at the bottom.

[StringJunky]

 

The current level of precision raises the question of "where are the atoms"?. If the lattice gives you a cloud of atoms 1 cm in diameter, then that will limit the precision; the clocks at the top tick at a different rate than at the bottom.

Wow! I never saw it like that; the dimensions of the device limit its accuracy. So, if you wanted to go more accurate, further miniaturisation is what's needed?

Edited May 11, 2015 by StringJunky

[swansont]

Wow! I never saw it like that; the dimensions of the device limit its accuracy. So, if you wanted to go more accurate, further miniaturisation is what's needed?

 

Yes. Ion clocks may have the upper hand in that regard, since the confinement region is smaller. Fountain clocks would never make it, since the atoms move about 30 cm (up and then down) while "ticking", though most of that happens near the apex, so the error introduced would probably be weighted that way and end up being smaller than 3x10^17 (which is the shift for ~30 cm). As it stands, it's not quite big enough to be noticeable for a fountain frequency standard.

[StringJunky]

 

Yes. Ion clocks may have the upper hand in that regard, since the confinement region is smaller. Fountain clocks would never make it, since the atoms move about 30 cm (up and then down) while "ticking", though most of that happens near the apex, so the error introduced would probably be weighted that way and end up being smaller than 3x10^17 (which is the shift for ~30 cm). As it stands, it's not quite big enough to be noticeable for a fountain frequency standard.

I'm impressed. I never realised, 'til now, the level of finesse that current physics is at with regards to GR/SR and their applications. Einstein's legacy is going to be around a very long time.

Edited May 11, 2015 by StringJunky

[DimaMazin]

 

So, as you have chosen a completely arbitrary number why not stick with the definition of the second that we already have.

I have given wrong example. We should use only meters. For example 1*10⁹m.

[Strange]

I have given wrong example. We should use only meters. For example 1*10⁹m.

 

But the meter is defined by how far light travels in a second! So you can't use that to define the unit of time.

Edited May 11, 2015 by Strange

[DimaMazin]

 

But the meter is defined by how far light travels in a second! So you can't use that to define the unit of time.

Initially meter was defined without light travel. Therefore I can define every thing without unit of time.

Edited May 12, 2015 by DimaMazin

[Klaynos]

But it was changed to be more accurate. Your method is less accurate and therefore a step backwards.

[Strange]

Initially meter was defined without light travel. Therefore I can define every thing without unit of time.

 

Yes, it was defined as the length of a metal rod in Paris. You want to go back to a poor quality standard like that. Why?

[DimaMazin]

 

Yes, it was defined as the length of a metal rod in Paris. You want to go back to a poor quality standard like that. Why?

And so people use inexact meter for definition of exact c . Then they use exact c for definition of exact meter. Why we can't use exact c for definition of exact time?

[swansont]

And so people use inexact meter for definition of exact c . Then they use exact c for definition of exact meter. Why we can't use exact c for definition of exact time?

 

 

You can't do both. It's circular to use c to define both the second and the meter, and realize one in terms of the other. You need an independent definition of one of them. As it stands, the realization of the second is the most precise standards measurement there is. Why would you want to compromise that?

[imatfaal]

And so people use inexact meter for definition of exact c . Then they use exact c for definition of exact meter. Why we can't use exact c for definition of exact time?

 

You have to have a base which you measure - and then things can flow from there. At present our base is a number of hyperfine transitions of caesium 133 which we say is equal to one second (9 192 631 770)

 

We then base the metre on the speed of light and the measured second. You need to tie your unit system down to a non-subjective basis - in this case counting

[DimaMazin]

 

You have to have a base which you measure - and then things can flow from there. At present our base is a number of hyperfine transitions of caesium 133 which we say is equal to one second (9 192 631 770)

 

We then base the metre on the speed of light and the measured second. You need to tie your unit system down to a non-subjective basis - in this case counting

Then time is just a count of quantities of motions by standard of simultaneity.

[StringJunky]

Then time is just a count of quantities of motions by standard of simultaneity.

No. Time is what clocks measure. A clock is not time itself.

[DimaMazin]

No. Time is what clocks measure. A clock is not time itself.

Clocks show quantity of own motion which is counted by standard of simultaneity.

Where did I say that time is a clock?

[StringJunky]

...Where did I say that time is a clock?

 

 

Then time is just a count of quantities of motions by standard of simultaneity.

Edited June 7, 2015 by StringJunky

[conway]

Is it then that this equation requires all things to have space? Including particles?

[Mordred]

Is it then that this equation requires all things to have space? Including particles?

How would you measure or define anything without space(volume) ?

 

Time is simply a measure of change or duration. How one measures it doesn't define time.

As the day the universe doesn't Care how we measure it.

 

(Key note to measure time you must have SOMETHING to measure ie particles either individual or as a body.)

Edited June 8, 2015 by Mordred

[DimaMazin]

 

Clock is mechanism of motions and of count of the motions, but clock isn't count. Clock can wrongly measure time when it measures motion by not standard of simultaneity. Therefore definition of time "time is what clocks measure" isn't scientific.

[ydoaPs]

No. Time is what clocks measure. A clock is not time itself.

Clocks don't measure time. Clocks measure states relative to other states. They measure other clocks.

[DimaMazin]

They measure other clocks.

You overestimate abilities of clocks.

[Strange]

Clocks show quantity of own motion which is counted by standard of simultaneity.

 

Clocks don't measure motion. They work perfectly well when stationary.

 

And I don't know what "counted by standard of simultaneity" means. Especially in regard to a single clock.

[DimaMazin]

 

Clocks don't measure motion. They work perfectly well when stationary.

 

I don't know a clock which doesn't create motions and doesn't count them.

[Strange]

I don't know a clock which doesn't create motions and doesn't count them.

 

The second is defined as: the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom at rest at a temperature of 0 K.

Edited June 8, 2015 by Strange