On 1/24/2013 10:38 AM, Jim Lux wrote:
On 1/24/13 7:24 AM, Mike S wrote:
On 1/23/2013 3:34 AM, Magnus Danielson wrote:
On 01/23/2013 02:32 AM, Mike S wrote:
Can you have a Cs under zero acceleration and at zero temperature, the
only conditions for which the second is defined? Since most metric
units
are derived from the definition of the second, are any "primary
standards," in your opinion?
Isn't it defined for zero sea-level, that is standard acceleration?
"At its 1997 meeting the CIPM affirmed that:
This definition refers to a caesium atom at rest at a temperature of 0
K." - http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html
Sea-level would be 1 g of acceleration, would it not?
which sea?
OK, "roughly 1 g," but that's missing the point. Which is, a real-world
device that realizes the definition of the second is (currently?)
impossible. That TAI is a weighted average of many "standards" I think
supports that - real world devices must be compensated to be close, but
still imperfect.
My question was in response to a claim that if "the number and type of
atoms in such a standard" (proposed 1 kg silicon sphere) couldn't be
counted, "its not a primary standard." The same logic could be applied
to the second, and all derived units.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
