Recent data from two spacecraft suggest the planet was mostly dry and cold, with a wet, warm subsurface. (p. 5)

On November 1, the formula for estimating the abundance of extraterrestrial life in our galaxy celebrates its 50th birthday. It’s known as the Drake equation for its creator, Frank Drake, who is also my father.

Cassini fits four Saturnian satellites in one frame.

The surprising composition and terrain of an asteroid may provide a variety of lessons about the solar system. (p. 14)

In July, the Ecuadorean navy helped apprehend a fishing vessel within the waters of the Galápagos National Park. On board lay the carcasses of 379 sharks — including threshers, hammer­heads, Galápagos, blues and a mako. Nearly severed fins hung from the mutilated, slippery bodies. The fins were presumably destined for trade in Asian markets, where shark-fin soup can sell for more than $100 a bowl. The incident is no aberration; these illegally slaughtered sharks are just the bloodied face of a global problem. Not even marine sanctuaries are immune. But sharks aren’t the only predators... (p. 26)

Suspended in the sky, the moon has stared unblinking at the Earth for billions of years. But new work suggests the placid sphere’s two faces may belie a violent childhood — one that involved the death of a small celestial companion. The moon may also be lying about when it was born, by millions of years. Together, the studies, published in August in Nature, lend a somewhat shady character to this perennial source of both fear and inspiration. With the Lunar Reconnaissance Orbiter already keeping a close eye on the moon (SN Online: 9/18/09) and the recently launched twin GRAIL spacecraft (... (p. 20)