Our Moon May Have Been Hit By a Dwarf Planet Long Ago

The moon's far side, as photographed by the Lunar Reconnaissance Orbiter (LRO) (Credit: NASA/GSFC/Arizona State University)The familiar lunar vista humans see when they look up at night reveals a face with dark "seas" and bright craters. The mysterious far side, which wasn’t revealed until humans started sending probes and then people in the 1960s, is far more heavily cratered, with few of the dark plains of the near side.
But what caused the two sides to be so different? That’s been