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[Phys-l] Response to Brian W



your note reminds me of this separate question:

As the universe is expanding at an accelerating pace, so that the

"furthest" light we can see is from 13 Bly or thereabouts,

and more distant light never can reach us,

is there an accounting for the mass and dark energy at these

larger separations?

Brian W


I just discovered I never responded to this.
My apology to Brian.

Actually even though the Universe
is 13.7 billion years old we actually see
light at a distance of about 46 billion light years.
This is because space time itself is expanding at
the light travels from distance stars. There is a
useful integral equation to calculate this distance
over any scale factor.

R= c*int { 0 to t_1} (t/t_0)^(-n) dt

Where observationally we set

n= 0.702 and t_0 = 13.7 BLY

This is an approximate equation but it works pretty well.

Bob Zannelli