Low levels of chlorine on planet's surface have long puzzled scientists. (p. 14)

What do five Porsches, several Kentucky thoroughbreds and a three-story building in Guatemala City have in common? They’ve all been swallowed by sinkholes. Sadly, the sudden cave-ins sometimes claim people’s lives as well. On February 28 the earth opened up underneath the Seffner, Fla., bedroom of Jeff Bush, entombing him. The freak accident highlighted Florida’s vulnerability to sinkholes, and the seemingly sheer randomness of death by earth. But geologists are fighting back. The battle isn’t just one man versus the ground; it’s science versus society’s tendency to put structur...

Methane, ozone and other short-lived pollutants have a big impact on ocean heights, simulation finds. (p. 20)