NASA's Hubble Space Telescope has provided the most detailed look yet at the comet hurtling toward a July 1994 collision with Jupiter.
The Hubble's high-resolution images show that approximately twenty objects make up comet P/Shoemaker-Levy 9, giving it the appearance of a string of pearls, and that these objects are much smaller than originally estimated from observations with ground-based telescopes. Measuring the size of the nuclei is very difficult because each nucleus is surrounded by a haze of dust, called a coma. The Hubble telescope provides improved contrast between the nuclei and their comae, thereby allowing a better estimate of the sizes. Some astronomers think the comet is really an asteroid from the asteroid belt between the orbits of Jupiter and Mars.