Ancient crashes blasted metals into Earth, moon and Mars

[MSNBC]  Gigantic collisions on Earth, the moon and Mars 4.5 billion years ago injected precious elements such as gold and platinum into the developing worlds, a new study suggests.

In the last days of planet formation, a body as big as Pluto likely slammed into Earth after the planet had been clobbered by a Mars-size object, researchers said. Mars and the moon absorbed smaller but still devastating blows, they added.  More...