What do they mean by ”observable universe?”
“What do they mean by ”observable universe?”
I presume he means anything that can be observed by our best telescopes. How many light years that is, I have no idea.
The distance away that light can travel during the entire history of the Universe. We can see out to about 14 billion light years, anything past that is over the “horizon” and is not observable. Our observable universe is a globe about 28 billion light years in diameter.
I’ve seen a few related articles that substitute Milky Way (our galaxy) for the term “observable universe”. I don’t know if that’s deliberate, or the writer’s interpretation of what the scientific papers are saying.