Billions of years ago, so the theory goes, something around the size of Mars smacked into Earth, spewing a whole bunch of dirt into space that eventually coalesced to form the Moon. This is called the ...

Hubble Space Telescope images have revealed a second massive collision between planetary bodies orbiting the nearby star ...

Eons ago, in the frigid depths of our solar system, a dramatic collision occurred between two icy worlds. Instead of a catastrophic smash-up, the two bodies "kissed," merging temporarily like a ...

How did the Moon form? Was it from a collision, as has been the longstanding theory, or could it have been captured by the Earth early in our planet’s formation? This is what a recent study published ...

Earth's calm and cool lunar companion may indeed once have been a roiling ball of molten rock, new research has found. The moon has been long theorized to have formed due to a Mars-sized planet named ...