Mysterious "blobs" deep inside Earth are "buried relics" from collision 4.5 billion years ago with another planet, study suggests

Scientists proposed a novel idea on Wednesday that could solve two of the world's mysteries at once — one that passes over our heads every night, and one that sits far below our feet.

The first mystery has puzzled everyone from scientists to inquisitive children for millennia: where did the moon come from?

The leading theory — known as the Giant Impact Hypothesis — is that the moon was created 4.5 billion years ago when a would-be planet the size of Mars smashed into the still-forming Earth.