# [time-nuts] Einstein Special on PBS

Bob Camp kb8tq at n1k.org
Sat Nov 28 08:01:23 EST 2015

```Hi

….but …

As part of the time steering of the system, the ground segment constantly plays games with the
total correction of each SV. Even with no offset, they still would bring it all into alignment. Yes it
would be a major pain to do so with a “couple of mHz” error in the mix. I suspect that there are
some pretty involved corrections that take care of just about anything that can be calculated.

Bob

> On Nov 28, 2015, at 5:16 AM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
>
> The trouble is that they experience different acceleration, due to gravity, and this yanks the experienced time. In the relativistic world, the concept of time is not consistent between locations, and the effect of acceleration between two locations shift it, and this is a consequence of a fixed speed of light. This is the consequences of fixed speed of light, that the rate of time needs to shift and this is the bizarreness of relativity that made many physics initially not accept relativity. Over the 100 years, we have seen again and again that this model actually makes sense for all the observations we have.
>
> Elevating a clock from the earth, alters it's experienced gravitational potential, the gravitational acceleration will be different. This is similar to sending the clock towards us in a constant rate. Our experience of their rate of time will be different, and so will they. Our gravitational acceleration will from the top of the mountain look like sending us away from them. For both cases the light speed is constant, so we can only yank the rate of time, because the physics of the clocks at each such location does not yank.
>
> Think of the oscillators being modeled as
>
> O1(t) = cos(2*pi*f0*T1(t))
> O2(t) = cos(2*pi*f0*T2(t))
>
> T1(t) and T2(t) being local time functions. With the clocks at the same location or otherwise similar locations, these will be about the same. The physics of the clock sets f0. It's only when we change the characteristics that alter T1 and T2 that we can observe that difference. The time t being here some arbitrary non-observable time.
>
> Usually we get away with letting T1 and T2 be t directly, but the fixed speed of light need us to alter these.
>
> If you now take two clocks of different physics (Cs and H-maser) and forms two pairs. One that stays and one that goes to the top. Each pair will be consistent, to the degree they are for normal systematics, but the mountain pair will both experience the same shift compared to the valley pair.
>
> Cheers,
> Magnus
>
> On 11/27/2015 07:10 PM, Mike Feher wrote:
>> Bob -
>>
>> Thanks for attempting to make me see the light. But, I still do not. You said it yourself that hyperfine transitions remain the same. Since "time" on these device are derived from these transitions, they should also remain the same. I agree, from a relativistic point of vie the time will be different. I am just not convinced that using these types of clocks will demonstrate that. Thanks - Mike
>>
>> Mike B. Feher, EOZ Inc.
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960 office
>> 908-902-3831 cell
>>
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob Stewart
>> Sent: Friday, November 27, 2015 12:48 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Einstein Special on PBS
>>
>> Hi Mike,
>> I'm far from an expert on this, but what you're missing is that time and space isn't the same between any two points that are located in different gravity gradients and/or moving at different relative velocities.  The hyperfine transitions are happening at the same local rate whether the Cs device is on planet earth, in orbit around the earth, or in close proximity to the sun or even a black hole.  But, all of these examples are happening in different space-time environments (i.e. different local frames), so that "relative" to each other, they are experiencing time at different rates.
>>
>> It might help to think of it in terms of doppler effect, though this is not an exact comparison.  But, if you have two clocks that are moving away from each other, they may very well be precisely synchronous, but because of the doppler effect, any measurement you make will show them to be running at different rates.  Because of the effects of gravity, watches at different altitudes appear to run at different rates to the outsider, although to the person wearing the watch, nothing has actually changed; it is the other person's watch that is acting funny.
>>
>> So, essentially, a clock sitting on the ground at sea level is running in a very slightly different space time than one that is sitting on a mountain.  And when you place a clock in orbit, you also have 14,000 odd MPH of velocity that's also having an impact on the space-time of that object.  As a result, when you bring the prodigal clock back to sea level, it will have experienced a slightly different amount of time than the one at sea level.  Note that the prodigal clock hasn't run at a different rate.  It has actually experienced time running at a different rate from that of the clock on the ground.
>>
>> Bob
>>
>>
>>
>>      From: Mike Feher <mfeher at eozinc.com>
>>  To: 'Discussion of precise time and frequency measurement' <time-nuts at febo.com>
>>  Sent: Friday, November 27, 2015 9:37 AM
>>  Subject: Re: [time-nuts] Einstein Special on PBS
>>
>> I just do not get it. I know that now I am 70 and my good smart days are behind me, but, this should be simple. In all these clocks mentioned, time is derived from the transition of a hyperfine line of a certain atom within some element, in this case cesium, In order for any of these clocks to deviate in relative time at different heights for example, it seems to me that the period of the hyperfine transitions must change as well, to make the defined second longer or shorter. So, in these examples the elevation does not change the time, but the way the atoms behave. What obvious item am I missing, besides maybe brain capacity? Thanks - Mike
>>
>> Mike B. Feher, EOZ Inc.
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960 office
>> 908-902-3831 cell
>>
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Tim Shoppa
>> Sent: Friday, November 27, 2015 9:19 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Einstein Special on PBS
>>
>> Would've been more fun to see Tom and his kids going to the top of Mt Ranier in 2005 with the ensemble :-). http://leapsecond.com/great2005/
>>
>> They mentioned some "6 miles per day" offset due to GPS relativity effects.
>> I think this is the sum of both special relativity (time dilation) and general relativity (gravitational) effects. The GR correction is 45 microseconds a day fast; the SR correction is 7 microseconds slow. 38 microseconds seconds is 11 kilometers which is indeed 6 or 7 miles. While time drifts 38 microseconds a day, I'm not sure that GPS coordinates would drift that fast - aren't most of the corrections in the same direction?
>>
>> Seeing Kip Thorne describe black holes was a blast - he refused to use the word mass when describing them, just like when I took a course from him in 1990. When my advisor taught the same course, I pleaded with him, "please use coordinates!". (Kip Thorne loves coordinate-free notation, unfortunately my brain does not work that way!!! I would've failed the course if it was only GR; fortunately it also had plasma physics in the same quarter, and I was an ace at that due to some undergraduate work.)
>>
>> Tim N3QE
>>
>> On Fri, Nov 27, 2015 at 12:05 AM, Arthur Dent <golgarfrincham at gmail.com>
>> wrote:
>>
>>> In the special it looks like they used two HP5071A standards, an
>>> SRS620 counter, and a scope. They first made sure the stds were in
>>> sync then took one to the building at the top of the ski lift on New
>>> Hampshire's Mount Sunapee at 2726' elevation for 4 days where it would
>>> be running a little faster because it would be slightly further from
>>> the center of the spinning earth. After bringing the 5071A back from
>>> the top of the mountain they checked the difference in the start of
>>> square waves displayed on the scope and detected the 5071A at altitude
>>> was now 20ns ahead of the 5071A kept at sea level, as predicted, if I
>>> understood everything correctly. They explained that the clocks in the
>>> GPS satellites traveling at a much higher speed had to correct for the
>>> speed difference which also verified Einstein's theory.
>>>
>>> My wife and I were on the top of Mt. Sunapee this summer where we
>>> enjoyed the views but didn't run any experiments. ;-)
>>>
>>> -Arthur
>>> _______________________________________________
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>>
>>>
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