Ask Ethan: How far is the edge of the Universe from the farthest galaxy?
Even with the greatest telescopes imaginable, there are billions of light years with nothing recognizable by today’s standards.
“Despite its name, the big bang theory is not really a theory of a bang at all. It is really only a theory of the aftermath of a bang.” -Alan Guth
When we look out into the Universe, there’s light everywhere we can see, for as far as our telescopes are capable of looking. But at some point, there’s a limit to what we’ll encounter. One limit is set by the cosmic structure that forms in the Universe: we can only see the stars, galaxies, etc., as long as they emit light. Without that ingredient, our telescopes can’t detect anything. But another limit, if we can use astronomy to go beyond starlight, is the limit of how much of the Universe is accessible to us since the Big Bang. These two values might not have much to do with one another, and that’s what Oleg Pestovsky wants to know!
Why is the redshift of CMB … around 1,000, while the highest redshift for any galaxy we have observed is 11?
The first thing we need to think about is exactly what happens in our Universe, moving forward, from the moment of the Big Bang.
