Jun 14 1995
From The Space Library
The Hubble Space Telescope has detected a long-sought population of comets dwelling at the icy fringe of the solar system. Based on the Hubble observations, astronomers estimate the belt contains at least 200 million comets. The existence of a comet belt encircling our solar system-like the rings of Saturn-was first hypothesized more than 40 years ago by astronomer Gerard Kuiper. The theory remained conjecture until 1992 when ground-based telescopes began detecting about 20 large icy bodies ranging from 60 to 200 miles in diameter. Hubble was able to identify objects just a few miles across. This region is thought to be the source of the short-period comets that orbit the Sun in less than 200 years. The planet Pluto is considered by astronomers to be the largest member of- the Kuiper Belt region. The comet-disk lies just beyond Neptune and might stretch 500 times farther from the Sun than Earth.
The Kuiper Belt is 100 times closer to Earth than the hypothesized Oort cloud, commonly thought to be a vast repository of comets tossed out of the early solar system. (NASA Release 95-88; NY Times, Jun 15/95; W Post, Jun 15/95; Discover, Nov 95; AV Wk, Aug 7/95; Science, Jun 23/95)
A new report on orbital debris has determined that the hazard to spacecraft posed by artificial debris, though still small, is growing and requires international action. Objects much smaller than those presently cataloged can destroy a spacecraft in a collision. Even collisions that do not destroy a space-craft can degrade its performance or cause it to fail. The report was funded by NASA and conducted by a committee of the National Research Council. (NASA Release 95-88; USA Today, Jun 14/95; Fla Today, Aug 26/95)
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