How big is the universe? Long considered one of the most perplexing questions, it's on the minds of many astronomers these days. Some even think they can answer it. In this media-rich essay from NOVA, Brent Tully, astronomer and co-producer of the NOVA film Runaway Universe, discusses astronomy's latest theories on the size—and shape—of the universe.
© 2015 PBS & WGBH Educational Foundation. All rights reserved.