![Wink ;-)](./images/smilies/icon_wink.gif)
The APOD explanation under the picture has the same number.
What I cannot understand are:
--1-- How did "we" [the mass comprising our galaxy and us] ever get in a position out in front of those light rays so that "we" are intercepting them now, if the universe is only about 14 billion years old?
How far and, most critically, fast have "we" travelled in that time?
--2-- Even more curiously, how can "we" be at the center of a sphere with a 13.7 billion light-year radius?
That puts opposite sides 27.4 billion light-years apart.
To my mind, there is a logical error in here somewhere.
Peace,
Phil [NOT a physics student] G
PS: where can I discuss other matters in their book, especially "vacuum energy" [p.43]?