The solar system’s spotted bully and its ringed sidekick are holding some tantalizing treasures in their gravitational clutches. Circling Jupiter and Saturn are more than a hundred moons, including some of the most promising hosts for extraterrestrial life in the solar system. But not every one of these moons is an equal opportunity extraterrestrial petri dish. Scientists are now debating which might be best for a life-seeking mission. Their attention is focused on a frozen trio: Titan, Enceladus and Europa. For centuries, these satellites appeared in the sky as mere points of light. Now, ... (p. 22)

On April 2, for the fifth time in less than three years, the International Space Station fired its engines to dodge a piece of orbital debris that appeared on a collision path. Other spacecraft also regularly scoot out of the way of rocket and satellite debris. Such evasive action will be needed increasingly frequently, a new study finds.

A huge shattered moon could have sprayed ice particles around the newborn planet. (p. 10)

Lava flow suggests recent volcanism on Earth’s nearest planetary neighbor.

A decade of droughts has stifled the increasing growth of terrestrial vegetation.

Whirlwinds leave dark paths behind by sucking sand grains clean.

Researchers discover a fresh meteorite impact crater using Google Earth. (p. 13)