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Questing1
2016-Aug-15, 07:38 AM
I was interested to learn recently, that advances have been made in the arena of atomic clocks, regarding their complexity, size, power consumption, cost etc. Turns out you can buy one the size of a stapler, for under US$1500. https://www.youtube.com/watch?v=Uc_4on62jLY

I've been on stack exchange asking questions, and it's starting to look very promising for a new pass time in amateur science, the measuring of time dilation. Great for those who have a large mountain nearby. http://physics.stackexchange.com/questions/273395/are-todays-chip-scale-atomic-clocks-accurate-enough-to-conduct-my-own-test-of-t

Note that my original question posed on stack exchange lists the accuracy of the chip scale atomic clock at 3.0 10-10 per month, but that might not be correct. It seams the clock maybe substantially more accurate 5.0 10-11. However the question still remains open, what sensitivity does this translate to in terms of measuring time dilation from Earths available mountain heights?

Anyway, this is just the kind of thing I thought this community would find interesting, and I've put it in Q&A so I might get to the bottom of its viability.

01101001
2016-Aug-15, 01:17 PM
Did you catch episode one of Genius by Stephen Hawking? (http://www.pbs.org/genius-by-stephen-hawking/episodes/episode-1/)

Project GREAT 2016a -- Hawking, Einstein, and Time Dilation on Mt Lemmon (http://www.leapsecond.com/great2016a/) describes helping the show with an entertaining experiment.

To me, it sounds boring -- confirming expected results -- and expensive -- multiple high-accuracy clocks -- so it's not my idea of time well spent, but if you think you can learn something by experiencing it, go for it. At least you can have a good time hiking the mountain and seeing sights.

Grey
2016-Aug-15, 02:11 PM
Project GREAT 2016a -- Hawking, Einstein, and Time Dilation on Mt Lemmon (http://www.leapsecond.com/great2016a/) describes helping the show with an entertaining experiment.Looking at this, it appears that the expected difference in two clocks separated by 2 km for about a day is on the order of 20 ns. The clocks they used were accurate to within about 2 ns per day. But looking at Symmetricon's video, it says the "aging" is 3.0 x 10-10 per month, but it doesn't give units. Does that mean seconds gained or lost on average per month? That would certainly be sufficient, but that's also about 2 orders of magnitude more precise than the clocks used for Project GREAT 2016a, so it seems surprising that they would be that good. Maybe that's some other way to state accuracy?

Grey
2016-Aug-15, 02:26 PM
Okay, a little reading tells me that the aging rate is the relative difference between measured time and actual time. So 3.0 x 10-10 means that the time measured will be 1 +/- 3.0 x 10-10 times the actual time elapsed. Quoting over a month simply means that this is how stable it is over a long term (their video also quotes a short term deviation of 2.5 x 10-10 on scales of a second). So that means that over a day, this clock would gain or lose an average of 25 microseconds. That's very accurate, but nowhere near sufficient to measure the ~20 nanosecond difference we'd need for a general relativity test using a nearby mountain.

Questing1
2016-Aug-16, 02:56 AM
Did you catch episode one of Genius by Stephen Hawking? (http://www.pbs.org/genius-by-stephen-hawking/episodes/episode-1/)

Project GREAT 2016a -- Hawking, Einstein, and Time Dilation on Mt Lemmon (http://www.leapsecond.com/great2016a/) describes helping the show with an entertaining experiment.

To me, it sounds boring -- confirming expected results -- and expensive -- multiple high-accuracy clocks -- so it's not my idea of time well spent, but if you think you can learn something by experiencing it, go for it. At least you can have a good time hiking the mountain and seeing sights.

No I havent watched Genius by Stephen Hawkings. I'll check out the link later.

I know the reality of measuring time dilation is quite boring, but there is no accounting for taste. I know a guy who has persisted a life long fascination for trains! go figure. So my guess is that if amateurs are given the capability, some will get a kick out of it. I might like to do it once.

Perhaps a progressive school teacher will take opportunity to close the text books, and make relativity a real and measurable thing for his/her students. Seeing serves a big part of believing. Just a thought

Questing1
2016-Aug-16, 03:00 AM
Okay, a little reading tells me that the aging rate is the relative difference between measured time and actual time. So 3.0 x 10-10 means that the time measured will be 1 +/- 3.0 x 10-10 times the actual time elapsed. Quoting over a month simply means that this is how stable it is over a long term (their video also quotes a short term deviation of 2.5 x 10-10 on scales of a second). So that means that over a day, this clock would gain or lose an average of 25 microseconds. That's very accurate, but nowhere near sufficient to measure the ~20 nanosecond difference we'd need for a general relativity test using a nearby mountain.

Thank you Grey. You would need to be high in orbit before this device would be useful for measuring time dilation. This tech is new. I think it a fair assumption it will be improved on over time, and perhaps be up to the task in the not to distant future.

01101001
2016-Aug-16, 03:32 PM
I've got a clock in orbit. Many of them.

Lazy version of proposed experiment:

1) Look at your smartphone GPS location and marvel at how well it reflects reality.

2) Silently thank the designers for having the wisdom to avoid accumulating 10 km of error per day by correcting for time dilation (https://en.wikipedia.org/wiki/Global_Positioning_System#History).

01101001
2016-Aug-16, 04:26 PM
Someone asked Quora: Is there a cheap experiment you can do at home that demonstrates time dilation? (https://www.quora.com/Is-there-a-cheap-experiment-you-can-do-at-home-that-demonstrates-time-dilation)

Viktor T Toth answered:


Cheap it may not be, but affordable by ordinary (first world) humans, perhaps it is: you may wish to buy two of these: Quantum™ SA.45s Chip Scale Atomic Clock (http://www.microsemi.com/products/timing-synchronization-systems/embedded-timing-solutions/components/sa-45s-chip-scale-atomic-clock#overview). Take one of them up a mountain 1000 meters above sea level. It should be ticking faster by about one part in ten billion (assuming I can use a calculator correctly), which is well within the measurement accuracy of these clocks. And the bonus is that this is actually a demonstration of general, not special, relativity.

But it sounds like he hasn't done it and is just calculating off published specs.

Jens
2016-Aug-17, 12:00 AM
Just on the subject, a guy I work with (http://www.riken.jp/en/pr/press/2015/20150210_1/) has built two clocks that are accurate to one part in like 10 to the minus 18th power, so it's kind of like it would take longer than the life of the universe for them to go out of synch by a second. He uses lasers to trap single atoms in a light lattice, so his laboratory is like a maze of mirrors and cryogenic stuff. I think he can measure elevation changes of just centimeters.

DaveC426913
2016-Aug-17, 12:44 AM
Did you catch episode one of Genius by Stephen Hawking? (http://www.pbs.org/genius-by-stephen-hawking/episodes/episode-1/)

Project GREAT 2016a -- Hawking, Einstein, and Time Dilation on Mt Lemmon (http://www.leapsecond.com/great2016a/) describes helping the show with an entertaining experiment.

Awesome! I saw this guy back in 2007, when he poaed his results from his 2005 experiment on top of Mt. Ranier in the back of his family van.

http://leapsecond.com/great2005/

You can indeed check relativity as an amateur!

http://leapsecond.com/great2005/great5c-320.gif

Questing1
2016-Aug-17, 01:18 AM
Someone asked Quora: Is there a cheap experiment you can do at home that demonstrates time dilation? (https://www.quora.com/Is-there-a-cheap-experiment-you-can-do-at-home-that-demonstrates-time-dilation)

Viktor T Toth answered:

But it sounds like he hasn't done it and is just calculating off published specs.

Thats a good find. Viktor is a prolific writer on the subject of relativity, and claims to have qualifications in the field. He's saying the chip scale atomic clock is up to the task. Promising

I have heard a variety of opinions on the question of chip viability, but no consensus to make my knowing easy. But I want to believe Viktor

Questing1
2016-Aug-17, 01:23 AM
I've got a clock in orbit. Many of them.

Lazy version of proposed experiment:

1) Look at your smartphone GPS location and marvel at how well it reflects reality.

2) Silently thank the designers for having the wisdom to avoid accumulating 10 km of error per day by correcting for time dilation (https://en.wikipedia.org/wiki/Global_Positioning_System#History).

haha lol yeah that works. But what about those who might want to conduct their own experiment in search for anomalies?

Questing1
2016-Aug-17, 01:42 AM
Just on the subject, a guy I work with (http://www.riken.jp/en/pr/press/2015/20150210_1/) has built two clocks that are accurate to one part in like 10 to the minus 18th power, so it's kind of like it would take longer than the life of the universe for them to go out of synch by a second. He uses lasers to trap single atoms in a light lattice, so his laboratory is like a maze of mirrors and cryogenic stuff. I think he can measure elevation changes of just centimeters.

Thats pretty awesome. Sounds like you have an interesting work environment. Measuring elevation changes of cm via time dilation. Freakily amazing

Questing1
2016-Aug-17, 01:43 AM
Awesome! I saw this guy back in 2007, when he poaed his results from his 2005 experiment on top of Mt. Ranier in the back of his family van.

http://leapsecond.com/great2005/

You can indeed check relativity as an amateur!

http://leapsecond.com/great2005/great5c-320.gif

Thanks Dave. I'll definitely check this out

Grey
2016-Aug-17, 06:58 PM
Thats a good find. Viktor is a prolific writer on the subject of relativity, and claims to have qualifications in the field. He's saying the chip scale atomic clock is up to the task. Promising

I have heard a variety of opinions on the question of chip viability, but no consensus to make my knowing easy. But I want to believe ViktorI think he must have messed up in his math. The fractional difference in time for a given change of height is gh/c2 (well, at least that's the linear approximation when we're talking about near the surface of the Earth, for changes in height that are small relative to the radius of the Earth; g is the acceleration due to gravity at Earth's surface, h is the difference in height between the two clocks, and c is the speed of light). So for the 1 km mountain he suggests, that comes out to a fractional difference of about 1.1 x 10-13, or about 3,000 times smaller than the rated accuracy for that clock chip.

Strange
2016-Aug-17, 07:13 PM
Awesome! I saw this guy back in 2007, when he poaed his results from his 2005 experiment on top of Mt. Ranier in the back of his family van.

Poaed?

LookingSkyward
2016-Aug-17, 07:26 PM
think it was sposed to be "posted"...

01101001
2016-Aug-17, 08:59 PM
But what about those who might want to conduct their own experiment in search for anomalies?

How did they enter this low-cost scenario? Won't they need a bit more accuracy firepower than offered by a consumer-grade part? If there was low-hanging fruit in the anomalies department wouldn't someone with a real budget have already scoped them out in recent decades?

But, I guess dreaming is free.

Questing1
2016-Aug-18, 04:37 AM
I think he must have messed up in his math. The fractional difference in time for a given change of height is gh/c2 (well, at least that's the linear approximation when we're talking about near the surface of the Earth, for changes in height that are small relative to the radius of the Earth; g is the acceleration due to gravity at Earth's surface, h is the difference in height between the two clocks, and c is the speed of light). So for the 1 km mountain he suggests, that comes out to a fractional difference of about 1.1 x 10-13, or about 3,000 times smaller than the rated accuracy for that clock chip.

Thats a shame. I wonder if somebody should let Viktor know. Thanks for the details on how to calculate for time dilation. I'm beginning to understand the parameters.

Is it a process of simply adding time dilation due to the suns gravitational field, to the value of time dilation as measured at Earths surface? What I mean is, does the sun effect time on Earths surface? Does the time dilation at Earths surface change if you move Earth into the outer solar system, for example?

Questing1
2016-Aug-18, 04:50 AM
How did they enter this low-cost scenario? Won't they need a bit more accuracy firepower than offered by a consumer-grade part? If there was low-hanging fruit in the anomalies department wouldn't someone with a real budget have already scoped them out in recent decades?

But, I guess dreaming is free.

:) like your willingness to make concessions for dreamers.Yes it seams they will have to wait for consumer grade parts to have increased accuracy.

The thing about low hanging fruits, they can be hanging right in front of you unnoticed, and therefore untested, without that necessary insight to draw your attention. Can you think of any excessable environments within which time dilation hasn't been test yet?

Grey
2016-Aug-18, 02:25 PM
Is it a process of simply adding time dilation due to the suns gravitational field, to the value of time dilation as measured at Earths surface? What I mean is, does the sun effect time on Earths surface? Does the time dilation at Earths surface change if you move Earth into the outer solar system, for example?Not significantly. Note the factor of g, the acceleration due to gravity, in that equation. The equivalent value for the Sun, measured at the distance of Earth, is about 0.006 m/s2, as opposed to Earth's 9.8 m/s2. The Sun's gravity is a lot stronger than Earth's (at the surface of the Sun, acceleration due to gravity is about 275 m/s2), but we're a lot farther away, so time dilation effects from the Sun's gravity are much smaller here.

Hornblower
2016-Aug-18, 10:34 PM
:) like your willingness to make concessions for dreamers.Yes it seams they will have to wait for consumer grade parts to have increased accuracy.

The thing about low hanging fruits, they can be hanging right in front of you unnoticed, and therefore untested, without that necessary insight to draw your attention. Can you think of any excessable environments within which time dilation hasn't been test yet?
What sort of environments are you thinking of here?

01101001
2016-Aug-19, 12:27 AM
Like, air temperature!

I'm sure there are an infinite number of ambient air temperatures at which you'll get unexpected results from your (or any) clock's time dilation measurement -- but it will be because your clock has melted, or just operates poorly out of a recommended range.

You're going to have to know your clock inside out to know if some environment breaks time dilation, leading to your Nobel Prize, or breaks your device, leading you to buy yet another clock.

Happy investigating of all those "anomalies".

DaveC426913
2016-Aug-19, 02:29 AM
think it was sposed to be "posted"...

Derp :o

Questing1
2016-Aug-19, 04:57 AM
What sort of environments are you thinking of here?

From within the Earths mass, which hasnt been tested so far as I can discern. Why it hasn't is a surprise, considering scientist have access to mine shafts +1km deep, and the little trickier ocean floor 11km below the Earths surface. My theory has implications for this experiment, which would lead to a higher rate of time dilation than conventional wisdom would predicted, but I'd have to ATM it to make a proper explanation. But anyway, thinking about this led to my inquiries concerning chip scale atomic clocks. I wondered if I could one day be the one to test it.

But I can say this much. We measure gravity within the solar system, and it can be considered an approximation of a one body gravitational system. The planets there in are massively overwhelmed by the suns gravity, and the planets conform to expected motions.

On the other hand you have galaxies, which can be described as a many body gravitational system, which demonstrate anomalous motions not only within its outer reaches, but also within its center. The transition of anomalous motion can be described as smooth from outer to inner galaxy, beginning with an over prediction of motion galaxy edge, and progressing through to an under prediction of motion galaxy center.

If the many body gravitation system has an undetermined dynamic which is responsible for this circumstance, that expresses itself as a measure of gravitational potential, then once you're moving within the body of the gravitating system, you would expect a deviated rate of time dilation from predictions. Sampling time dilation from within the Earths mass, might present a test for such anomalies. If you want a specific answer to why I think this result might show up, then please PM me.

But regardless of my eccentric ideas, its not such a difficult test to perform. I know many will be satisfied with their assumed results, but thats not really adequate is it? But please dont forget that I predict this deviation from predictions here now. Still working on how to calculate my specific prediction, but I think I'm making progress in this direction.

Got to be in it to win it

Questing1
2016-Aug-19, 04:59 AM
Like, air temperature!

I'm sure there are an infinite number of ambient air temperatures at which you'll get unexpected results from your (or any) clock's time dilation measurement -- but it will be because your clock has melted, or just operates poorly out of a recommended range.

You're going to have to know your clock inside out to know if some environment breaks time dilation, leading to your Nobel Prize, or breaks your device, leading you to buy yet another clock.

Happy investigating of all those "anomalies".

Thank you for your support :) you dont want to come underground with me, or for a swim?

a1call
2016-Aug-19, 06:43 AM
One thing you might consider is Pulsar time keeping:


Today, the best optical lattice neutral atom clocks and trapped ion clocks have a frequency stability approaching one part in 10^17.By contrast, as more pulsars have been discovered, their timing stability has improved by less than an order of magnitude in the last 20 years. The best millisecond pulsars have a stability of only one part in 10^15 at best.

https://www.technologyreview.com/s/418326/where-is-the-best-clock-in-the-universe/

I wonder how synced two video feeds of a single pulsar from within 2 differing in magnitude gravity fields, would be? Considering they have had aeons to diverge. That is, if you can somehow sync the feeds, perhaps using sufficiently accurate clocks to keep in sync long enough to carry the cameras to the observation fields and the duration of the observation.

Questing1
2016-Aug-19, 08:32 AM
One thing you might consider is Pulsar time keeping:



https://www.technologyreview.com/s/418326/where-is-the-best-clock-in-the-universe/

I wonder how synced two video feeds of a single pulsar from within 2 differing in magnitude gravity fields, would be? Considering they have had aeons to diverge. That is, if you can somehow sync the feeds, perhaps using sufficiently accurate clocks to keep in sync long enough to carry the cameras to the observation fields and the duration of the observation.

Thats an interesting review. I think I'll have an easier time getting an atomic clock down a mine shaft than a pulsar however :) But if you have one laying around doing nothing, I'll be happy to make you an offer

Questing1
2016-Aug-19, 08:54 AM
I believe I have reason to believe, everything you need to know about dark energy, and dark matter is encoded within Einsteins equation Guv + Auv = tuv, in an incredibly unsuspectingly simple way. Anybody spent time considering the various balances throughout the elements of this equation? Things surely dont just balance like that without reason, good and justifiable reason.

Guv = Tuv
Auv is set to balance Guv
So Auv also equals Tuv. I guess thats where Dirac derived the large numbers hypothesis from.

Auv "universal expansion" as measured by red-shift shares a balanced ratio with value of universal "mass" Tuv?

Isnt it curious how Einstein conjured up Auv purely as a need to balance his equation, nothing more. Then that same value, that same measure, only very much later became an observational truth of universal expansion, but still somehow equivalent to universal mass, as his original application demanded. Who in the room considers themselves a detective?

That flat universe issue we have measured, with the implication that in all time past the universe suffered positive spacetime curvature, and in all time future it will suffer negative curvature? But that would require Guv + Auv = Tuv suffer changing values. How could Auv “universal expansion” maintain parity with Tuv “universal mass” if the value of Auv was variable over time?

01101001
2016-Aug-19, 11:39 AM
Thank you for your support :) you dont want to come underground with me, or for a swim?

I live at the bottom of an ocean of air. Have you checked with the people who have real clocks, the ones who can measure time dilation by putting their clock on a 30cm molehill instead of a mountain? They operate at the bottom of the same ocean. How does the mass of air above change their measurements? Are they freaking out?

Questing1
2016-Aug-19, 12:32 PM
I live at the bottom of an ocean of air. Have you checked with the people who have real clocks, the ones who can measure time dilation by putting their clock on a 30cm molehill instead of a mountain? They operate at the bottom of the same ocean. How does the mass of air above change their measurements? Are they freaking out?

Thats actually a good point, and it tells me youre giving thought. I suggest its a density of mass thing. The atmosphere might be a little thin to make for an obvious effect. I could be crackers obviously, but if I was right, I suspect even at depth within the Earth the deviations on predicted time dilation will be conservative. But measurable.