On Thursday, July 9, 2015 at 6:35:44 AM UTC+2, Barry Schwarz wrote:
On Wed, 8 Jul 2015 18:22:54 -0700 (PDT),
wrote:

Somebody said :

"There is a bad part in being a photon born in one of the greatest supernova explosions. You fly for 10 gigayears,
pass 10 billion parsecs and end up somewhere on the dirty road, dog poop, Morbid's red hair and almost every
human and non-human ****. At least, photons don't care... Good for them in being so abundant, omnipresent, patient and powerful, not like us"

This doesn't sit right with me, is there something wrong with this statement? Is the greatest supernova that far away?

A parsec is about 3.26 light years. The maximum distance a photon can
travel in 10 billion years is 10 billion light years. 10 billion
parsecs would be 32.6 billion light years. So yes, someone's
arithmetic is off.

I don't know about greatest supernova but since the universe is
estimated to be 13+ billion years old it seems reasonable that the
oldest supernova could be 10 billion years old. If the photons are
just reaching us now then it probably was 10 billion light years away
but not 10 billion parsecs away.

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Thankue soo much smart person!