1. Higgs: What causes the weight of the world

A decades-long, multibillion-dollar search paid off last July when physicists at the Large Hadron Collider near Geneva announced that they had discovered the Higgs boson, a particle so fundamental that without it there would be no atoms in the universe—and therefore no stars, no planets, and no one to wonder about it all. "It's kind of profound," says Joe Incandela, a physicist at the University of California, Santa Barbara, spokesman for one of the two teams that made the discovery and a master of scientific understatement. "We're still absorbing it ourselves. We've touched on something now that really is way beyond anything we’ve done before."