[LEAPSECS] Nit-pick: SI second

[Paul Sheer]

Since the velocity of the atomic clock causes relativistic dilation,
surely it is not the altitude-above-sea-level, but the radial distance
from the earths axis that we are talking about???

I.e. surely both latitude and altitude affect the ceasium? I mean the
velocity of the atomic clock as it stands in the lab is dictated by the
earth rotation times the radial distance from the earths rotational
axis?

???

-paul


On Thu, 2011-02-10 at 00:24 +0100, Magnus Danielson wrote:

> On 07/02/11 20:10, Tom Van Baak wrote:

> >> It is also why TAI's rate was adjusted in the 1990's to compensate for

> >> the red-shifted data that had been collected at NIST in Boulder, since

> >> it sits at about 5400' (1700m) above sea level (as well as other

> >> facilities not at sea level).

> >>

> >> Warner

> >

> > Are you sure you aren't confusing red shift (which has been

> > a known factor since the 60's) with blackbody shift (which

> > only arose in the 90's as clocks hit the 1e-15 level)?

> 

> These are distinct in the face of SI. The nit-picker could find all the 

> material needed in

> 

> http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf

>