John Smith wrote:
Could you elaborate a bit ... I lost you somewhere? I mean I understand
time could not be measured in earth years before the earth existed ...
but after it did exist (and we invented time based on its' spinning)
can't we just extrapolate backwards? Or, what?

As you know, relativistic effects change the length of
seconds. Just after the Big Bang, everything must have
been traveling close to the speed of light. (The inflation
of the universe is supposed to have happened at much faster
than the speed of light.) But what if seconds were
simply extremely long due to velocity. As the particles
slowed down, seconds got shorter until today we have the
shortest second ever to exist - shorter than it was
yesterday. Now take today's short second, lay them end
to end, and extrapolate the age of the universe. You
get a number that is much too large. Conceptually, but
not to scale:

BB|------------------------------------|first second ...
.... |--|today's second

What if the first second was actually one trillion of
our present-day seconds? Extrapolation would lead to
an error of 12 magnitudes in the length of that first
second.

Not only are there time effects - there are also space
effects. Things are not getting farther away from each
other - light-years are getting longer as we speak, i.e.
space itself is expanding, i.e. the standard meter in
the National Bureau of Standards is getting longer as
we speak.

What happens when me measure the light frequency of
distant galaxies while, during the travel of that
light, light-years were getting longer and seconds
were getting shorter? Hint: same thing that happens
when the time base knob on an oscilloscope gets loose
and slips. (That actually happened to me and the
result was an epiphany about space/time.)
--
73, Cecil http://www.w5dxp.com