Contemporary physics has captured the public imagination by juxtaposing staggeringly tiny measurements with vast unknowns. The Large Hadron Collider, the enormous particle collider in Switzerland, can measure subatomic particles down to a tenth of a thousandth of a trillionth of a millimeter--and from studying how matter behaves at such small scales, physicists infer how our entire cosmos is structured.
Lisa Randall is one of the most-cited theoretical physicists of the last two decades, and one of the best-known scientists in any field: In 2007, Time named her one of the world’s 100 most influential people. Among other things, Randall’s work links the subatomic and cosmic by suggesting an answer to the “hierarchy problem,” the puzzling relative weakness of gravity among the four fundamental forces binding matter together. Gravity’s pull is much weaker than the other forces, Randall posits, because the universe has a tiny additional dimension absorbing more gravitational force. The “warped” geometry of this cosmic model, developed with physicist Raman Sundrum, includes two branes, or regions of space, with different levels of gravity; we inhabit the low-gravity area.