[time-nuts] Time Dilation tinkering
Bob Bownes
bownes at gmail.com
Thu Mar 23 02:59:04 UTC 2017
It's not getting one past the airport authorities that's the issue. It's getting one that's powered up past them. ;)
Written from about 10,000'. :)
> On Mar 22, 2017, at 20:15, Tom Van Baak <tvb at LeapSecond.com> wrote:
>
> Chris Albertson wrote:
>> Why drive up a mountain?
>
> "Because it's there" ;-) And because there's a paved road, and it's free, and there's a place to stay overnight, and the mountain doesn't move. Plus a car makes a good portable time lab; you can share the experience with family or students or visiting time nuts; and a number of technical reasons.
>
> But most importantly: you can remain at altitude as long as you want -- in order to accumulate just enough nanoseconds of time dilation to meet your experiment's S/N goal -- without running into (or much worse, going beyond) the flicker floor of your clocks.
>
> There are several different ways to measure time dilation with atomic clocks. Some notes here:
> http://leapsecond.com/pages/atomic-tom/
>
>
>> Take the clock with you inside the pressurized cabin of a commercial airliner
>
> Yes, and this has been done many times. The first (1971) and most famous of all traveling clock relativity experiments is:
> https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment
>
> For vintage hp flying clock articles see:
> https://www.febo.com/pipermail/time-nuts/2013-January/073743.html
>
> Two modern examples are described here:
>
> "Time flies"
> http://www.npl.co.uk/news/time-flies
>
> "Demonstrating Relativity by Flying Atomic Clocks"
> http://www.npl.co.uk/upload/pdf/metromnia_issue18.pdf
>
> /tvb
>
> ----- Original Message -----
> From: Chris Albertson
> To: Tom Van Baak ; Discussion of precise time and frequency measurement
> Sent: Tuesday, March 21, 2017 7:12 PM
> Subject: Re: [time-nuts] Time Dilation tinkering
>
> "flight" there is the word. Why drive up a mountain? Take the clock with you inside the pressurized cabin of a commercial airliner next time you are on one of those 10 hour trans=pacific flights. You be taller then any mountain and it is actually cheaper then a weather balloon.
>
> Can you get a Rb clock past the TSA x-ray machine. Maybe if you ask first. There must be a way to hand cary specialized equipment.
>
> On Tue, Mar 21, 2017 at 7:03 PM, Tom Van Baak <tvb at leapsecond.com> wrote:
>
> But attached is one of the first plots where I put a SA.32m in a home-brew vacuum chamber and pulled down to a few inches of Hg for a few hours to simulate the low pressure of a flight up to 50 or 90,000 ft. For a high altitude relativity experiment -- where you'd like your clock to remain stable to parts in e-13 and not accumulate too many stray ns -- it's not a good sign when your clock changes by 2e-11 (that's more than 1 ns per minute) just because of ambient pressure changes.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the Time-nuts_lists.febo.com
mailing list