Redefining the SI unit (second)

[Grayman]

http://physics.nist.gov/cuu/Units/second.html

Spoiler

Unit of time (second) Abbreviations: CGPM, CIPM, BIPM


The unit of time, the second, was defined originally as the fraction 1/86 400 of the mean solar day. The exact definition of "mean solar day" was left to astronomical theories. However, measurement showed that irregularities in the rotation of the Earth could not be taken into account by the theory and have the effect that this definition does not allow the required accuracy to be achieved. In order to define the unit of time more precisely, the 11th CGPM (1960) adopted a definition given by the International Astronomical Union which was based on the tropical year. Experimental work had, however, already shown that an atomic standard of time-interval, based on a transition between two energy levels of an atom or a molecule, could be realized and reproduced much more precisely. Considering that a very precise definition of the unit of time is indispensable for the International System, the 13th CGPM (1967) decided to replace the definition of the second by the following (affirmed by the CIPM in 1997 that this definition refers to a cesium atom in its ground state at a temperature of 0 K):

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

Generally when a unit is defined in science a reference is created based on certain conditions. In the case of the 'second' the cesium frequency is measured at 0 Kelvin.

This ensures that the second does not change depending on temperature.

Why don't they adjust for gravity and acceleration? Shouldn't the second be defined as the frequency of cesium at 0 Kelvin and 0 Gravity and no Acceleration?

If they did redefine the second as such, then time would be the same anywhere because the reference would be adjusted to the conditions.


An example is that Celsius is defined as

Of or relating to a temperature scale that registers the freezing point of water as 0° and the boiling point as 100° under normal atmospheric pressure.

If the atmospheric pressure was altered then Celsius does not change but it is adjusted to the new conditions. If you had abnormal atm pressure and the water was boiling it would be incorrect to say that the temperature is 100 deg Celsius.


If the second were to be redefined to include this condition of gravity and acceleration then 1 second in earths gravity would be exactly 1 second in space at the satellite.

Of course time travel would then be impossible since a second is a second is a second is a second no matter what.

 

[Black Rose]

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

How many meters is this? I think light travels 1 meter a billionth of a second. I do not know the radius of the orbital of the ground state level of cesium 133. (what are hyperfine levels?)

 

[Turnevies]

According to general relativity, spacetime is bended in a smooth way so that at a sufficiently small scale it looks flat. This means that if you and your clock are together in a gravitational field, you will not be able to tell the difference from being in a perfectly flat (minkovski) space by performing local experiments. This means that the time you measure on your clock really is the most truthful time along your path in spacetime. And there is no unambiguous way to compare times at two different places in spacetime.

 

[Grayman]

How many meters is this? I think light travels 1 meter a billionth of a second. I do not know the radius of the orbital of the ground state level of cesium 133. (what are hyperfine levels?)

https://www.bing.com/videos/search?...2527792E89CFAE001EE62527792E89CFA&FORM=VRDGAR

 

[Grayman]

And there is no unambiguous way to compare times at two different places in spacetime.

Frequencies are redshifted/blueshifted by increased mass gravity. This frequency shift should be adjusted for so that 1 second will pass the same on earth as it does in space when measuring the frequency of cesium as is done in an atomic clock.

The point of units is to eliminate relativity so that apples are compared to apples.

 

[Black Rose]

https://www.bing.com/videos/search?...2527792E89CFAE001EE62527792E89CFA&FORM=VRDGAR

Thanks

Frequencies are redshifted/blueshifted by increased mass gravity. This frequency shift should be adjusted for so that 1 second will pass the same on earth as it does in space when measuring the frequency of cesium as is done in an atomic clock.

The point of units is to eliminate relativity so that apples are compared to apples.

If relativity is eliminated then does this mean heisenberg uncertainty is no longer in effect? Two devices will know the velocity and position of each out at the same time? Plank scale is 1.0*10^(-42). This would be the accuracy of the device.

 

[Grayman]

Thanks



If relativity is eliminated then does this mean heisenberg uncertainty is no longer in effect? Two devices will know the velocity and position of each out at the same time? Plank scale is 1.0*10^(-42). This would be the accuracy of the device.

Speed and time are relative in that they depend on the reference point. That is the way physics functions. Time does not actually exist except to define the distance between to actions or events. (Distance not being physical but energetic).

I am saying that units of measure are not relative in the same way. They are designed to be based on a standard or specified reference so that when a unit of measure (second, Meter, Gallon, CubicFoot) is used we can have a baseline or reference point already agreed upon and defined so that we are comparing apples to apples and not apples to oranges.

A second shouldn't be shorter or longer just because it is in a stronger or weaker gravitational field.

 

[Grayman]

Thanks



If relativity is eliminated then does this mean heisenberg uncertainty is no longer in effect? Two devices will know the velocity and position of each out at the same time? Plank scale is 1.0*10^(-42). This would be the accuracy of the device.

What does the Heisenberg principle have to do with the Theory of relativity?

 

[Turnevies]

Frequencies are redshifted/blueshifted by increased mass gravity. This frequency shift should be adjusted for so that 1 second will pass the same on earth as it does in space when measuring the frequency of cesium as is done in an atomic clock.

The point of units is to eliminate relativity so that apples are compared to apples.

When you are in space floating next to the satellite, there is no way you can percieve the fact that any clock has 'slowed down', because your body and brain also run slower, this is fundamentally different from e.g. switching on a magnet. And there is no unique definition of events being simultaneous on earth as in the satellite. The only way to compare two clocks is when they were made together, took a different path through spacetime and are rejoin in the end.

The fact that you cannot compare times at different points in space has to do with Parallel transport: it is only possible to shift a vector along a manifold from any point A to point B in a unique way if that manifold is flat To give an example: if you have an arrow in America that points to the east and you shift it to the nord pole straight away, it will point in another direction than if you first shift it to Russia and then to the nord pole. This is because Earth's surface is curved. According to GR, mass curves spacetime similarly.

Those concerns aside, maybe you are right in the sense that it would be possible (and fundamentally better) to define a second on earth in terms of the transitions of a masless hypothetical cesium atom freely floating were earth is now but without earth. But off course, then there is still the mass of the sun, and the rest of the galaxy...

 

[Grayman]

When you are in space floating next to the satellite, there is no way you can percieve the fact that any clock has 'slowed down', because your body and brain also run slower, this is fundamentally different from e.g. switching on a magnet. And there is no unique definition of events being simultaneous on earth as in the satellite. The only way to compare two clocks is when they were made together, took a different path through spacetime and are rejoin in the end.

I am not interested in pseudoscience. There is no evidence of anything being slowed due to gravity and acceleration besides an atomic clock. To say that time itself is slowing because your clock is off is a bit of a stretch.

 

[Turnevies]

I am not interested in pseudoscience. There is no evidence of anything being slowed due to gravity and acceleration besides an atomic clock. To say that time itself is slowing because your clock is off is a bit of a stretch.

I know I am a new one on this forum, so I'm not in a position to show off much authority. But I assure you that I am not telling bullshit about this one. I took a graduate-level GR class last autumn based on Sean Caroll's textbook, which is currently a few meters away from me. Even the wikipedia page https://en.wikipedia.org/wiki/Gravitational_time_dilation describes time dilatation generally, for generic clocks without referring to the technical details of how this clock should work.

Also note that even without gravitational time dilation, a clock in a satellite will get an ofset from a clock on earth due to the relative velocity which results in a time dilation predicted by special relativity.

 

[Brontosaurie]

It still wouldn't make one hell of a difference due to the lack of GI directional pairmaters.

 

[Grayman]

I know I am a new one on this forum, so I'm not in a position to show off much authority. But I assure you that I am not telling bullshit about this one. I took a graduate-level GR class last autumn based on Sean Caroll's textbook, which is currently a few meters away from me. Even the wikipedia page https://en.wikipedia.org/wiki/Gravitational_time_dilation describes time dilatation generally, for generic clocks without referring to the technical details of how this clock should work.

Also note that even without gravitational time dilation, a clock in a satellite will get an ofset from a clock on earth due to the relative velocity which results in a time dilation predicted by special relativity.

Isn't it important to understand the fundamentals of how gravity is effecting the clock? The atomic clock uses light frequency emitted from a cesium atom. It wouldn't be surprising that gravity (GR) would effect the clock in the exact way that light would be effected by gravity being that the clock uses light to function.

But how do you go from light slowing down in a gravitation field to all forms of energy slowing down? What about thermal conduction and the transfer of electrons from atom to atom (electrical) and the absorption of photons or chemical bonding(chemical reactions)? Do these processes occur faster and what has been done to prove that these things occur at a faster rate as well and do so at the same rate as the atomic clock increased/decreased?

What we know is that gravity distorts time as a function of movement and velocity but what we don't know is if it effects complex systems that involve various forms of energy like 'human aging' and if it does just how much and in what way.

This wasn't really about intellectual authority. If it was I would have to side with what you are saying since the vast majority of science supports what you are saying.
I just want things to be fully supported and tested and to avoid any assumptions when calling it science.

 

[Turnevies]

Isn't it important to understand the fundamentals of how gravity is effecting the clock? The atomic clock uses light frequency emitted from a cesium atom. It wouldn't be surprising that gravity (GR) would effect the clock in the exact way that light would be effected by gravity being that the clock uses light to function.

But how do you go from light slowing down in a gravitation field to all forms of energy slowing down? What about thermal conduction and the transfer of electrons from atom to atom (electrical) and the absorption of photons or chemical bonding(chemical reactions)? Do these processes occur faster and what has been done to prove that these things occur at a faster rate as well and do so at the same rate as the atomic clock increased/decreased?

What we know is that gravity distorts time as a function of movement and velocity but what we don't know is if it effects complex systems that involve various forms of energy like 'human aging' and if it does just how much and in what way.

This wasn't really about intellectual authority. If it was I would have to side with what you are saying since the vast majority of science supports what you are saying.
I just want things to be fully supported and tested and to avoid any assumptions when calling it science.

Ok well, you can always make op your own alternative theories of course, but the current theory has pretty nice symmetry properties.

With the abreviation GR I was referring to General Relativity btw, if you have more interest in this subject, I'd recommend the series of lectures by Susskind on http://theoreticalminimum.com/.

 

[Grayman]

Ok well, you can always make op your own alternative theories of course, but the current theory has pretty nice symmetry properties.

With the abreviation GR I was referring to General Relativity btw, if you have more interest in this subject, I'd recommend the series of lectures by Susskind on http://theoreticalminimum.com/.

My proposal in the OP would make more sense if science didn't abandon aeather physics in favor of Einstein's theories. I am not inventing new theories. I am using age old classical science. Aeather can explain things that GR cannot. It can explain how light has wavelike properties. It can also explain the same things that GR can, it can explain how light slows in stronger gravitational fields even though it doesn't lose its velocity.

http://aetherpages.com/

The michealson Morely experiment was believed to be the proof that the aether did not exist but it was not proof it was just that they needed to adjust the theory. They assumed that the aether was directional or moving the same throughout the universe but it would make more sense to tie the aether to gravitational forces.

Example: http://aetherpages.com/gravity.htm

Not all clocks get affected similarly by gravity- atomic clocks tick slowly and pendulum clocks go fast with increasing gravity. If time itself was being effected by gravity all clocks would react the same regardless of type. Aether could help explain why the two clocks would react in opposite ways if you consider how the clocks work and how that causes it to react the way it does.