How big is the universe anyhow? We know the universe is roughly 4 billion years old and we know how far light travels in a year, so ostensibly it would seem the visible universe is contained to a radius of 14 billion light years. But we know that photons in the cosmic microwave background have traveled some 45 billion light years to reach earth (because the universe is also expanding the most distant visible objects are actually further than 14 billion light years), giving the universe an apparent diameter of at least 90 billion light years.
So how big is it really? A new mathematical analysis says its at least 250 times larger than the visible universe. Which is really, really big.