[time-nuts] Re: Project Great

[Bob kb8tq]

Hi

The CSAC is not a cesium in the conventional sense. It is much closer to 
a telecom Rb than anything else. There likely are telecom Rb’s that would
do a better job. Would they do a good enough job? …. likely not ….

Bob

> On Nov 27, 2021, at 5:11 PM, Lux, Jim <jim at luxfamily.com> wrote:
> 
> On 11/27/21 12:37 PM, Thomas Valerio wrote:
>> I think that Tom's GREAT adventure is kind of what sealed the deal making
>> me a time-nut or at least a time-nuts lurker, a lot of this stuff is still
>> little over my head, but I keep reading.
>> 
>> If anyone is inclined and has the clocks and the kids ( I don't have
>> either ), there is always Mount Evans and Pikes Peak, although you may
>> have to leave the clocks behind overnight.  Mount Evans is still on my
>> bucket list but without clocks and two or three days of time to monitor
>> them, I don't think I will be doing the Mount Evans edition of GREAT.  For
>> anyone that is flush enough to afford or can beg, borrow or steal access
>> to a Microsemi chip scale atomic clock, I think a Mount Evans edition
>> would be an awesome addition to Tom's original work.
>> 
>>    Thomas Valerio
>> 
> I don't think a CSAC would be good enough.
> 
> Tom's experiment was 22 ns out of 42 hours or about 1.45E-13. That's quite a bit smaller than a CSAC adev over that period.
> 
> There's a variety of roads that go to ~12,000 ft in Colorado, about ~10,000 in CA (Tioga Pass isn't closed yet), so you can get about 3x change, but still you're talking <1E-12.
> 
> Mammoth Mtn has a gondola to the top, but it's only 11,000. There may be a ski resort in CO that's higher.
> 
> 
>>> For newcomers to time-nuts, Andy is asking about my DIY gravitational
>>> time dilation experiment(s).
>>> 
>>>  > What am I missing?
>>> 
>>> It looks like you used the wrong value (or wrong units) for "h".
>>> 
>>> The summit of Mt Rainier is 14411 ft (4400 m), but the highest point on
>>> Mt Rainier that is accessible by road is the Paradise visitors center at
>>> 5400 ft. Our house is at 1000 ft elevation so the net difference in
>>> elevation of the clocks was 4400 ft (1340 m).
>>> 
>>> The clock(s) on the mountain ran fast by gh/c² = 9.8 × 1340 / (3e8)² =
>>> 1.5e-13. Fast clocks gain time. We stayed for about 42 hours so the net
>>> time dilation was 42×3600 × gh/c² = 22 ns.
>>> 
>>> ----
>>> 
>>> For more information see the Project G.R.E.A.T. 2005 page:
>>> 
>>> http://leapsecond.com/great2005/
>>> 
>>> Better yet, these two recent talks from 2018 and 2020 cover all 3 GREAT
>>> experiments:
>>> 
>>> <http://web.stanford.edu/group/scpnt/pnt/PNT18/presentation_files/I08-VanBaak-GPS_Flying_Clocks_and_Relativity.pdf>
>>> 
>>> <http://leapsecond.com/ptti2020/2020-PTTI-tvb-Atomic-Timekeeping-Hobby.pdf>
>>> 
>>> Lots of time nutty photos in both of those!
>>> 
>>> /tvb
>>> 
>>> 
>>> On 11/27/2021 7:33 AM, Andy Talbot wrote:
>>>> Just been reading your adventures with 3 Cs clocks, a mountain and 3
>>>> kids,
>>>> but I can't make the estimate of time dilation work out.
>>>> You measured ~ 23ns and say it agrees with calculation
>>>> 
>>>> The equation quoted in a related reference, for "low elevations" is
>>>> g.h/c²
>>>> which if you plug in g = 9.81 m/s²  and h = 4300m for Mt Rainer gives
>>>> an
>>>> expected value of 4.7 * 10^-16.
>>>> Over 2 days, 2 * 86400s, that would be 81 ns in total, four times your
>>>> value
>>>> 
>>>> What am I missing?
>>>> 
>>>> Was just speculating what Ben Nevis at a mere 1340m height might offer
>>>> 
>>>> Andy
>>>> www.g4jnt.com
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