Why does space look so dark?
Stars twinkle up above, but space itself is as dark as can be. (ESA/Hubble & NASA, A. Bellini et al./)We know you are bored at home right now—we are too. Here are some puzzles and brainteasers to challenge your family and friends with, either in person or over video chat.If you look up on a clear night, you’ll likely see a few bright celestial objects—and a lot of dark space between them. But if there are hundreds of billions of stars in our galaxy and hundreds of billions of galaxies in the universe, the whole thing should light up like Times Square. So why is the cosmos pitch-black at night?It isn’t. We just can’t see most of these interstellar billboards. Space is full of light energy on a spectrum from high-energy gamma rays to low-energy radio waves, says Mark Hammergren, an astronomer at Chicago’s Adler Planetarium. Our eyes can see...