Jim Kelley wrote:
Cecil Moore wrote:
The definition is relative, not absolute.

It's as absolute as anything we have. Name something absolute we could
have used instead, Cecil.

Please don't blame the messenger. If we could locate
an atomic clock at the center of gravity of the Big
Bang, we might have an absolute reference point -
(assuming that point is not moving. :-)

If the
relative speed of the earth is changing, then the
length of a second is also changing and we would
have no way of knowing.

Not to worry. Any relativistic motion on our part will only effect the
clocks in the other reference frames. And we can't even communicate
with any of those people. :-)

But, Jim, that other reference frame may be yesterday
on Earth. A second today may be shorter than a second
was yesterday. I can prove that seconds are getting
shorter. It takes me many more seconds to run 100
yards than it once did.

I'm pretty sure that first second after the Big
Bang wasn't anywhere near the length of a second now.
--
73, Cecil http://www.w5dxp.com