Moon formed in massive collision with Earth

The moon was formed from a gigantic smash-up in which a huge planet collided with the Earth, according to two new studies.

The terrific impact caused the Earth to spin so fast that a day lasted only two to three hours, allowing megatons of debris to spin off into space.

This planetary wreckage then solidified into a disk that would form our moon, according to SETI researchers.

The young Earth, or proto-Earth, and the impactor that crash-tackled it were approximately equal in size, claims another new study also supporting the planetary impact theory.

"This type of impact has not been advocated for the Earth-moon before,” said Robin Canup, of the Southwest Research Institute in an interview with Space.com.

“[However], a similar type of collision has been invoked for the origin of the Pluto-Charon pair,” she added, referring to Pluto’s largest moon.

The SETI finding, that a fast-spinning earth likely threw off planetary chunks which formed the moon, plugs a hole in earlier theories of the moon’s birth.

It was previously thought that the moon must have been formed by portions of the impactor planet, a puzzling conundrum for scientists who knew how close the moon’s composition was to Earth’s.

Taken together, the discoveries take scientists one giant leap closer to uncovering the origins of our moon, a mystery 4.5 billion years old.