The galaxy is 33 billion light years away now but the light started coming toward is when it was 13 billion light years away. The article is basically an introduction to this concept mentioned toward the end of the article:
“To avoid confusion, astronomers actually use two distance measurement scales: a co-moving distance that eliminates the expansion of the universe as a factor and a proper distance that includes it. That means the co-moving distance of JADES-GS-z14-0 is 13.5 billion light-years, while its proper distance is 33.8 billion light-years.”
I am just guessing, but if a galaxy was 10 billion light years away when the light left the galaxy it would appear to be 10 billion light years away, but in an expanding universe that galaxy also moved away from us for 10 billion years. So, appearing 10 billion years away today might mean it’s 30 billion light years away right at this moment in time.
If the universe isn’t 33.8 billion years old, how did that light make it here in 33.8 billion years?
Genuine question, I hope the article answers it. Bookmarking this for later while I return to writhing in bed recovering from a stomach bug…
The galaxy is 33 billion light years away now but the light started coming toward is when it was 13 billion light years away. The article is basically an introduction to this concept mentioned toward the end of the article:
“To avoid confusion, astronomers actually use two distance measurement scales: a co-moving distance that eliminates the expansion of the universe as a factor and a proper distance that includes it. That means the co-moving distance of JADES-GS-z14-0 is 13.5 billion light-years, while its proper distance is 33.8 billion light-years.”
Oops ! That article citation mixed them up … the comoving is the 33.8 one here … while the light travel distance is the 13.5.
Oh, gotcha, thanks for responding. That makes a lot of sense. Space at that scale gets so weird with timey wimey stuff
I am just guessing, but if a galaxy was 10 billion light years away when the light left the galaxy it would appear to be 10 billion light years away, but in an expanding universe that galaxy also moved away from us for 10 billion years. So, appearing 10 billion years away today might mean it’s 30 billion light years away right at this moment in time.