Breakthrough of the year. The runners-up.

SEEING MIGHT BE BELIEVING, BUT FOR SCIENTISTS BELIEF RARELY depends on seeing. The right squiggles coming out of an instrument are usually enough to confirm that they have caught their quarry, however infinitesimal, insubstantial, or bizarre. Astronomers searching for planets circling other stars, however, may have been getting just a tad impatient with their progress toward their ultimate goal: recognizing a habitable, even an inhabited, planet beyond our own solar system. For that, they’ll need to see their target. But all exoplanet detections had been of the squiggly variety. Now, astronomers have seen exoplanets for the first time—a halfdozen candidates have been announced in the past few months. To some, the new observations may simply have replaced squiggles with dots. But the faint pinpricks of light from far-off worlds have captured the public’s imagination and will give astronomers new clues to what those distant planets are made of and how they were formed. Key to these direct detections have been big telescopes and the latest technology to pick out a vanishingly faint planet from its host star’s overwhelming glare. Previous, indirect detections of more than 300 exoplanets had provided breakthroughs of their own. For 13 years, astronomers have been finding exoplanets using ground-based telescopes to monitor the subtle wobble a planet gravitationally induces in its star. This workhorse radialvelocity technique is especially useful for finding massive “hot Jupiters” searingly close to their star. No light is seen from the planet,