[LEAPSECS] Nit-pick: SI second
Rob Seaman
seaman at noao.edu
Thu Feb 10 18:17:49 EST 2011
Oooh! Google "Sagnac" and you also get lots of trendy pseudoscience from sites like anti-relativity.com. What fun!
--
On Feb 10, 2011, at 4:01 PM, Mark Calabretta wrote:
>
> On Thu 2011/02/10 07:18:53 -0800, "Tom Van Baak" wrote
> in a message to: "Leap Second Discussion List" <leapsecs at leapsecond.com>
>
>> Yes, the radius of the earth is slightly dependent on latitude,
>> perhaps that's what you're thinking about. But a clock at sea
>> level at lat 0 will run the same as and a clock at sea level at
>> lat 45 or lat 90 because that's what MSL is - the equipotential
>> surface of the geoid.
>
> A clock at the equator has a tangential velocity of 500m/s
> whereas for one at the pole it is 0m/s. The difference,
> amounts to about 100ns/day as per your later calculations.
> This is the Sagnac effect of Special Relativity.
>
> Regards,
> Mark Calabretta
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