[time-nuts] Time Dilation tinkering
eb4apl at gmail.com
Thu Mar 23 09:43:11 EDT 2017
Not mentioning that the clock traveled in a passenger seat (even with
the seat belt fastened). The vision of a big box with cables and a good
sized clock ticking (it was a Patek Philippe movement in early HP
Cesiums) frightened some passengers and the person accompanying the
clock had to give a lot of explanations. The use of the word "atomic"
worsened things somewhat.
(Memories from Apollo flights good times)
El 23/03/2017 a las 12:33, Bob Camp escribió:
> Back before GPS and similar systems, hauling Cs standards on commercial aircraft was
> a bit more common than it is today. One of the critical tricks of the trade was knowing where
> each power outlet was on a specific plane and how close it was to this or that seat. The next
> trick was knowing how to talk the crew into letting you plug the gizmo in the seat next to yours
> into that outlet. Sometimes the magic worked and other times you had to depend on your
> battery pack. Needless to say, getting through the over ocean travel process with a dead
> standard was not good news.
>> On Mar 22, 2017, at 10:59 PM, Bob Bownes <bownes at gmail.com> wrote:
>> 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:
>>>> 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:
>>> For vintage hp flying clock articles see:
>>> Two modern examples are described here:
>>> "Time flies"
>>> "Demonstrating Relativity by Flying Atomic Clocks"
>>> ----- 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.
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