A PREVIOUSLY UNDETECTED STREAM OF COMETS buffets the Earth. Apparently up to 30 comets per minute approach our planet, where they innocuously break up, releasing a river of water and organic compounds into the atmosphere. The trajectories of the comets are heralded by visible tracks (sunlight reflecting from OH molecules) observed by the Polar Spacecraft, parked in an eccentric orbit, the better to view the whole Earth. Louis Frank of the University of Iowa reported this new finding at last week's AGU meeting in Baltimore. In 1986 Frank proposed that not only were tiny ice comets arriving in great numbers but that their cumulative cargo of water might have fully stocked the oceans. This hypothesis, mostly dismissed at the time, will be re-examined now. The issues of exactly how many comets, how much water, and which organic molecules will be addressed by further observations, perhaps by military satellites. (Pictures and more information at Physics News Graphics.)