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.)

MORE QUALMS ABOUT EXTRASOLAR PLANET DISCOVERIES. The presence of planets around a number of stars has been inferred from the slight doppler wobble in the stars' spectra. One critic, David Grey of the University of Western Ontario, contends that the wobble, at least in the case of the star 51 Pegasi, may be due to the unstable nature of the star itself (Nature, 27 February). A second reservation has since surfaced. Caltech scientists, using an interferometer, suspect that 51 Pegasi is really a binary star system, and that this would account for the wobble (Science, 30 May).

CELESTIAL HEAVYWEIGHTS. The following items are a selection from a list compiled in the June 1997 issue of Astronomy. The largest known star is Mu Cephei (with a radius of 11 AU). The most massive star is Eta Carinae (100 solar masses). The largest known meteorite in the ground (an estimated 60 tons) lies in a farm in Namibia. The largest dug-up meteorite, the "Ahnighito" (34 tons), is on view in New York's American Museum of Natural History. The furthest galaxy (a distinction which changes frequently) is an unnamed object in Virgo with a redshift of 4.38. The most distant known object is the quasar PC 1247+3406, with a redshift of 4.897. The brightest recorded supernova occurred in the year 1006. As bright as a quarter moon, the object was visible in daylight and cast shadows at night.

THE MOST EXTENSIVE USE OF PERMANENT MAGNETS at an accelerator will be an important part of Fermilab's upgraded beamline system. The magnets (which provide stable fields and require no input current) will be used to help shuttle protons through beampipes prior to injection into the main accelerator ring. The magnets will also be used in the Antiproton Recycler Ring, a sort of waiting area for antiprotons. Expert machining of the pole faces ensures that the magnets meet the exacting tolerances required for steering high-speed particles. (CERN Courier, May 1997.)

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