Mars and other rocky planets formed 4.5 billion years ago. During this time, massive collisions shaped their early surfaces. Researchers believe planet-sized objects struck Mars in violent impacts.

Despite seeming like Earth's twin, Venus is a strange and mysterious place. Scientists haven't known what made it so odd, but that might have just changed.

Dyed-in-the-wool, leather-clad punk rockers stand shoulder to shoulder with teenage hipsters as they wait for the wristband exchange to open; you get the sense that, with dozens of acts playing across ...