Tue Feb 21 23:57:21 EST 2017

```This short paper was issued by NIST researchers in 2010, and it
discusses making accurate gravitational time dilation / redshift
measurements using lasers:
http://tf.boulder.nist.gov/general/pdf/2447.pdf

Quoting that paper:

> Differences in gravitational potential can be detected by comparing
> the tick rate of two clocks. For small height changes on the surface
> of Earth, a clock that is higher by a distance Δh runs faster by
>

> Δf/fo = g Δh/c2

>
> where g ≈ 9.80 m/s2 is the local acceleration due to gravity. The
> gravitational shift corresponds to a clock shift of about 1.1 × 10−16
> per meter of change in height.

So at your laboratory depth of 1.1 km, the fractional frequency change
1.2 x 10-13     (1.2 parts in 10^13)

--

Bill Byrom N5BB

On Tue, Feb 21, 2017, at 11:13 AM, Rhoderick Beery wrote:

> I'm a physics theorist interested in performing an experiment
> to measure
> the gravitational time dilation beneath the surface of the
> Earth. Boulby
> Labs in the UK is 1.1 km down which would generate a time differential
> fromthe surface on the order of 1 part in 10^15 -- not much to
> work with!

```