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.

These traumatic cosmic crashes may have knocked Earth off its axis by 10 degrees. But they also delivered gold and other elements into the bodies' upper reaches, and possibly brought huge amounts of water to the moon, researchers said.

"We can use this information to tell us about the last great growth spurt of the Earth, moon and Mars," said study leader Bill Bottke of the Southwest Research Institute in Boulder, Colo. [ MSNBC NEWS ]