Re: space time

On 21 Aug 2006 07:43:04 -0700, "Dwib" <dwibdwib@xxxxxxxxx> wrote:

Dick wrote:
So how far does light travel while the earth rotates one earth-sun
period?

1 light-year, no time needed.

Now is where things get strange. We may conceive of ways for the
earth-sun period to be changed

That is an issue of standards and not physics.

Wasn't there an English king defined a "yard" as the distance from his
nose to his outstreched fingertip? That's fine for that moment but
what happens when a new king/queen comes to power?

Likewise, a lightyear (as a measurement of distance) must be properly
tied to an actual distance standard like 9.4E15 meters or 5.6
quadgillion wavelengths of the red neon emission.

Dwib

A meter is a standard by definition. Light year looks like a
definition, but it is built on the earth orbit around the sun. As the
sun burns mass, the gravitational pull between the sun and earth will
lessen and the radius, thus circumference will increase resulting in
more time for light to travel as the year is now longer.

Light year is also strange because it is a limited measure. Only so
many kilometers in a earth-year, fewer but never more.

Since Light year has a natural size, I think it should be tied to some
part of the beginning of expansion. Probably a multiple of the radius
as the Singularity moved out. Lacking earth and sun for comparison
and assuming gravity existed, then the expansion radius relative to
gravity would seem to be the most obvious candidates.

I gather Planck's constants relate to the beginnings. I don't read
mathematics. Leave that to others.

dick

.

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