There doesn't seem to be a law that cleary demonstrates true regularity of any physical process. Every clock is imperfect. All we've done is postponed the event when our clocks will accumulate enough error to be noticeable. While this may be acceptable in living im the seconds, minutes, hours, days, months or years, we can't ignore it in doing science where accuracy is vital.
The physical process has to be regular. In my OP I mentioned how this is ''less'' of a problem with other quantities like length, mass, volume because we have a standard whose state has been specified. With time it's different because we can never be sure of the regularity of a time piece. We can't be 100% certain that one period of a cesium atom takes the same time as the next. — TheMadFool
They ran for a period of a month, and they got out of phase by 2.8 x 10^-17 seconds. That doesn't mean it's only proven to be stable for a month. Quite the contrary, the error is so low in a month that it's negligible. — fdrake
In the case of the atomic clock, there is no regular process. The clock is tuned to a constant of a physical system, and the second is thus DEFINED. The only "regularity" is that all the atoms have the same physical property, which, since we know they are indistinguishable, is a non-issue. — tom
You're always going to have measurement error in experiments. 5.4*10^-17 error in a second is ridiculously precise. As the optical lattice clock paper noted at the end - this level of precision allows all kinds of new experiments. The need for no measurement error to demonstrate anything through experiment has the opposite effect than 'accuracy is vital for the progress of science', since it completely undermines every single experiment ever done. — fdrake
Time, on the other hand, is slightly different. A unit like second can only be defined with periodic change that has to be regular, just like for length. But, without a time piece that is already regular we can't determine if the periodic phenomena we're using to measure time with is regular or not. See...?
Regularity is critical in all measurements. Consider a student's ruler. If the centimeter markings are spaced differently (the should be spaced the exact same length) then the ruler is "broken". Similarly, if the seconds ticked off by a clock are of different "lengths" then time measurement would be pointless. — TheMadFool
What allows the extrapolation of the error - and thus statements like '1 second in 100 million years' - is that the clock had a certain error which accrued over a month. The measurement error precisely gives 'how much it changes over time'. — fdrake
Yes there is such a law, and it is used in the articles linked. They've demonstrated the accuracy of some clock to X digits, and not by using a more accurate one.There doesn't seem to be a law that cleary demonstrates true regularity of any physical process. — TheMadFool
The laws of physics have been shown to operate over all observed parts of the universe - and thus back in time more than that. — fdrake
It isn't a stretch to assume if no one destroys the clock or the measuring mechanism, or turns it off, that the process operating within it that measures time will have that error rate. — fdrake
Yes there is such a law, and it is used in the articles linked. They've demonstrated the accuracy of some clock to X digits, and not by using a more accurate one.
You seem to just want to deny any answer to your query. So what's your purpose in asking then? — noAxioms
The SI unit of time is defined in terms of a property of matter. — tom
My problem with the existence of a law that demonstrates the regularity of a periodic process is that time, space, and other physical quantities are more fundamental than any law of nature. First comes measurement, whether time, mass, volume, distance, etc., and only then can relationships between these quantities can be seen. — TheMadFool
My physics isn't that good but look at the wikipedia article on the pendulum. The period, supposed to be regular, T = 2pi[(L/g)^0.5] where L = length of the pendulum and g is acceleration due to gravity. As you can see before we can derive this law, we need to know T, L and g. In other words, we already need a clock to measure time (T). How do we know that that clock is keeping accurate time? — TheMadFool
How does the argument go then? — fdrake
However, the universe will still be in the same regime of energy distribution for billions of years, and there is no good reason to believe that the laws will change in this time. — fdrake
What scientists believe about dark energy has absolutely no bearing on whether the laws of the universe will change in a given time period. Coming to know more about the laws of the universe may reveal the reason for all the 'missing matter', but this novel disclosure has no bearing on whether the laws will change - only what the laws are believed/known to be. With that in mind: — fdrake
Can you make a positive argument that the laws of the universe will change within 100 million years? Can you establish that the measurement process going on inside an atomic clock or an optical lattice clock will degrade? When will it degrade? How will it degrade? — fdrake
I understood you were making the claim that since the laws of the universe can possibly change. I'm not making the claim that it's impossible to change. I'm making the claim that they won't change in any meaningful way for 1000 times longer than the current age of the universe.
Why would you think that because it's possible for the universe's laws to change, that they will? — fdrake
Why would you think that because it's possible for the universe's laws to change, that they will? — fdrake
The claim that the laws won't change in that time is based on 1) that the current understanding of things is basically correct and 2) that this current understanding entails that the universe will be much the same for that time period. — fdrake
Even if science is wrong, that doesn't mean nature will change. Nature does not change to accommodate the beliefs of scientists. The scientific description of patterns in nature may change when previous descriptions are found incorrect or novel phenomena are studied. — fdrake
OK, then how do you make 1) consistent with dark energy and dark matter? These are enormous features of the universe which cosmologists admit that they do not understand. How can you say that the current understanding is correct, when the consequence of that understanding is the need to posit all of this mysterious substance?
If your claim is that the universe is the way that it is, regardless of how we understand it, then how is this relevant? What we are discussing is our capacity to measure the universe, specifically to measure time. So the fact that time is how time is, is irrelevant to our discussion of our efforts to measure time.
Basically correct. If you want to talk about dark energy, you have to be able to accept solutions to Einstein's field equations as correct and the web of theory and experiment around them. Dark energy only makes sense as a concept on the background of the acceleration of the expansion of the universe; and is contained in a few explanations of it. — fdrake
Your argument so far has been based on an equivocation of the following: the beliefs of scientists and the practice which generates them; usually called science, and the phenomena they study; usually called nature. If a pattern is observed in nature, and it becomes sufficiently theorised and experimentally corroborated, it will be a scientific law. Note that nature behaved that way first, the scientists adjusted their beliefs and inquiries to track the phenomenon. — fdrake
You want to have it so that the changes in the beliefs of scientists over the ages implies that nature itself has changed over that time. — fdrake
You keep attempting to justify the idea that assigning a small measurement error to an optical lattice clock is unjustified because the laws of nature possibly will change. Besides being an invalid argument - the laws of nature would have to change , not just possibly change, in order to invalidate the current error analysis of the clock, you're using the above equivocation to justify it. — fdrake
You thus have to show that the laws of nature (read - how nature behaves) will change in a way that invalidates the error analysis of the clock within 100 million years. — fdrake
very suspicious to me that something you could have understood by reading the papers thoroughly and researching the things you didn't know to enough standard to interpret the results, but now you're attempting to invalidate a particular error analysis of a clock by either the cosmological claim that the way nature operates will change in some time period or undermining the understanding that scientists have of reality in general. Engage the papers on their own terms, show that the laws of the universe will change (not will possibly change), or stop seeing nails because you have a hammer! — fdrake
Can you tell me how their combination entails:
(11) The measurement error analysis of the caesium-133 clock and the optical lattice clock are wrong. — fdrake
Ok. If the measurement error analysis in the paper isn't wrong, that means the 1 second in 100 million years isn't wrong. Since that corresponds to an error rate of about 3 * 10 ^ -16, which was derived within the month, — fdrake
If the measurement error analysis in the paper isn't wrong, that means the 1 second in 100 million years isn't wrong. Since that corresponds to an error rate of about 3 * 10 ^ -16, which was derived within the month. The unit of the error rate is in seconds per second... Take the reciprocal, voila! — fdrake
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