[time-nuts] Re: Gravity Meter was:Re: Scandium plus hard x-rays

[Tom Van Baak]

Brooke,

 > There are a number of ways to measure gravity,
 > but the best that I know of is the Super conducting type.

There is at least one commercial model available. Start here:

https://www.gwrinstruments.com/pdf/principles-of-operation.pdf

For more practical high-performance gravimeters, see the six models 
listed at this site:

 Â Â Â  https://microglacoste.com/shop/

If you want wonderful details a full set of brochures and manuals is 
available under the Support tab.

 > Tom's experiment with moving an atomic clock would give you
 > the a rough translation factor between gravity and time

Yes, relativity theory predicts -- and many experiments confirm -- that 
gravity affects time. The closer to a massive object you get the lower 
the frequency (called redshift) of your clock. For planet earth the 
fractional change in frequency, df/f, is approximately 1e-16 per meter, 
or 1e-13 per km. I think that's what you meant by translation factor. 
It's very, very small.

Note that a frequency difference of 1e-13 is a phase drift of about 10 
ns per day. This means if you have clocks that are good to 1e-14 and you 
perform a 1 km experiment (one clock low, one clock high) for 2 days 
you'll see about 20 ns of time dilation. This actually works, as you 
know from the hp 5071A experiments I've done on different mountains over 
the years.

 > I don't think GPS can be used ...
 > Something Tom maybe could comment on.

I don't understand that paragraph. Please clarify so I don't go off on a 
tangent.

/tvb


On 10/4/2023 11:59 AM, Brooke Clarke via time-nuts wrote:
> Hi Rick:
>
> There are a number of ways to measure gravity, but the best that I 
> know of is the Super conducting type.
> One of these was used to cancel the Earth's tide motion of a telescope 
> used for ranging retro-reflectors on the Moon.  i.e. good enough to 
> detect feet/inches of movement of granite rock.
> https://prc68.com/I/GravityMeters.shtml#Super_Conducting
>
> Tom's experiment with moving an atomic clock would give you the a 
> rough translation factor between gravity and time, if like me you're 
> not conversant with Einstein's equations.
> My guess is that the above gravity meter would be good to much better 
> than a part in 10,000.
>
> I don't think GPS can be used since placing a GPS antenna on an atomic 
> clock would probably result in no signal.  And running an atomic clock 
> in a location with a clear view of the sky may  not be the best 
> location interms of clock accuracy.  Something Tom maybe could comment 
> on.
>