Swimming in the Rain Particles sinking from sunlit surface waters through the ocean?s dimly lit twilight zone are swept sideways by currents. Conventional moored or tethered traps designed to catch the particles are like ?rain gauges in hurricanes,? said WHOI geochemist Ken Buesseler. He and engineer Jim Valdes are designing a new-generation neutrally buoyant untethered vehicle called the Twilight Zone Explorer, which is swept along with the currents. It surfaces periodically to relay data via satellite. (Illustration by Jack Cook, Woods Hole Oceanographic Institution)
