Contentious report on a controversial astronomical claim--that the earth is being bombarded by small comets--by Frank (Physics/Univ. of Iowa), the author of the theory, and Huyghe, a free-lance science writer. According to Frank, 20 of these mini-comets, each ""about the size of a small house,"" hit the atmosphere every minute. That's ten million a year. Since these comets are essentially water mist with a pinch of dust, this means that the earth is bathed in comet-juice; this may explain the source of the oceans, the periodic extinction of species (including the dinosaurs), the cause of ice ages, and even the origin of life. Needless to say, such a wide-ranging theory crunches heavily on many scientific toes, and much of the fun here lies in Frank's acrimonious clashes with colleagues who see their own pet theories in jeopardy. He takes potshots at Nature and Science for ridiculing his ideas, plumps for the existence of a ""Dark Planet"" beyond Pluto that ""shakes billions of comets loose"" on their earthward journey, and otherwise proves himself to be art endearing scientific outlaw. Frank insists that his small comets have now been seen by a specially designed optical telescope. A number of astronomers don't agree, and even as Frank rashes off on his latest project--scanning the moon for flashes of lights and other signs of comet-collision--his big splash is still, to many in the scientific establishment, just a drop of moonshine.