NASA Rover Drills Martian Rock, Looks for More Clues to Wet Past

The Curiosity rover became the first- ever robot probe to drill into Martian rock as it collected a sample that may reveal further clues about a wet environment in the planet’s past. The hole, which measures 0.63 inches (1.6 centimeters) wide and 2.5 inches deep, was visible in images and other …