PLANETARY SCIENCE:
Tiny Comets' Spots Called Artifacts
Richard A. Kerr
At a geophysics meeting last spring, space physicist Louis Frank of the University of Iowa in Iowa City flashed stunning satellite images on a screen, showing dark spots silhouetted against the ultraviolet (UV) glow of Earth's upper atmosphere. Those spots, he said, restored to grace his discredited 1986 theory that Earth is pelted with small comets daily. Now an analysis of UV images from a similar camera on the same satellite suggests that the mysterious spots are nothing more than instrument artifacts.