Number 214 (Story #1), February 16, 1995 by Phillip F. Schewe and Ben Stein GAS-GIANT PLANETS SUCH AS JUPITER must grow up in a hurry. New radio telescope observations by a UCLA-Grenoble-MIT collaboration of gas around 20 young stars show that within only a few million years of the star's formation excess gas, which could have contributed to the formation of planets, is lost from the juvenile solar systems. The observations suggest that for many of these stars there would not have been nearly enough gas to build a Jupiter, much less a Saturn. The astronomers conclude that if Jupiter-sized planets are common in our galaxy, they must form more speedily than current theories allow. If, however, Jupiters are rare, then the actual presence of the gas giant in our solar system is particularly fortuitous. George Wetherill of the Carnegie Institute believes that Jupiter and Saturn "may be essential to life" on Earth because of their role in sweeping up comets (e.g., Shoemaker-Levy) that might otherwise have snuffed out life on Earth. (B. Zuckerman et al., Nature, 9 February 1995.)