Blobs near Earth’s core are remnants of collision with another planet, study says

Artist’s impression of Theia colliding with a young Earth 4.5bn years ago, an impact that scientists say ended up making the Earth larger. Photograph: Hernán Cañellas

Mysterious blobs that lurk more than 1,000 miles underground may be remnants of a Mars-sized planet which slammed into Earth in the early solar system and produced a shower of debris that formed the moon, researchers say.

According to scientists’ leading theory, the moon was created about 4.5bn years ago when an ancient protoplanet named Theia thumped into the fledgling Earth. At the time, our home planet was still an infant and only about 85% of its size today.