The Elephant in the Universe

An award-winning science journalist details the quest to isolate and understand dark matter—and shows how that search has helped us to understand the universe we inhabit.

When you train a telescope on outer space, you can see luminous galaxies, nebulae,stars, and planets. But if you add all that together, it constitutes only 15 percent of the matter in the universe. Despite decades of research, the nature of the remaining 85 percent is unknown. We call it dark matter.