Blobs beneath the Earth could be remains of planet: Research

Mysterious blobs found 1,000 miles beneath the Earth's surface may be remnants of a Mars-sized planet that collided with Earth, creating debris that formed the moon, according to research. The blobs, known as large low-velocity provinces (LLVPs), were discovered by seismologists but their origins were unknown. Computer simulations suggest that the collision caused the upper portion of Earth's mantle to melt, with some of the material sinking towards the core over billions of years to form the blobs.