Ask Ethan: Do Ancient Galaxies Get Magnified By The Expanding Universe?
“Do ancient galaxies appear larger to us than they really were, due to the expansion of the Universe? If so, then by how much?”
It seems like the simplest, most straightforward idea in the world: the farther away an object is, the smaller it appears. View the same object when it’s twice as far away, and it will only appear to be half as large in terms of angular size. Place it ten times as far away, and you’ll see it appear just one-tenth the size.
But this is only true in flat, static space. In the expanding Universe, this relationship falls apart, particularly when you factor in dark energy. More distant objects appear smaller the farther away you look, but only to a point. Galaxies that are about 14-to-15 billion light-years away will appear the smallest, and then the same-sized galaxy will actually appear larger the farther away you look! This may be counterintuitive, but there’s real, solid science to back it up.
Come learn how the expanding Universe really does magnify the most distant galaxies of all, and what the fascinating implications are for the next generation of ultra-powerful telescopes!
