On Aprıl 10 the U.S. research vessel Thomas G. Thompson will steam 900 kilometers northeast from New Zealand and stop in the wide open Pacific Ocean. If all goes according to plan, it will drop Nereus, a robotic vehicle the size of a subcompact car. Nereus will dive, and dive, and dive down to one of the deepest and most hostile places on earth: the Kermadec Trench. It will hit bottom at just beyond 10,000 meters—the extent of Mount Everest, plus a modest Smoky Mountain. There, in frigid, absolute darkness, under water pressure of 15,000 pounds per square inch—the equivalent of three SUVs pushing down on your big toe—Nereus will shine its lights on the unknown. A video camera will stream imagery back up to the Thompson along a drifting, fiber-optic filament the width of a human hair, which Nereus will have spooled out as it sank.