If the universe is 13.8 billion years old, how is the observable universe 46.5 billion light years across?
In: Physics
The Universe is expanding, it’s been expanding for billions of years at about this rate. Across the visible Universe, the edges are expanding at a speed greater than the speed of light.
I heard it explained nicely by a loaf of bread rising with raisins in it. The raisins aren’t moving that much compared to the swelling dough between them. Maybe that analogy helps? Otherwise u/WRSaunders is right. Space is itself expanding faster than light can cover the distance.
Light years is a measure of distance and not a measure of time. Hopefully I’m writing enough to warrant a post
Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space.
*Douglas Adams, The Hitchhiker’s Guide to the Galaxy*
Lightyear is a measurement of distance. It’s how long light can travel in one year. One light year is 5.879 × 10^12 miles. It’s an estimate of how large the universe is, not how old it is.