The Moon's Two Sides Look So Different Thanks To 4.5 Billion-Year-Old Physics (forbes.com)
StartsWithABang writes: 4.5 billion years ago, a giant object collided with our proto-Earth, kicking up debris that eventually coalesced into the Moon. While the near side contains dark maria and lunar lowlands, the far side is almost exclusive heavily cratered, high-mountainous regions. This was a mystery for a long time, but it appears that heating from the hot, young Earth caused a chemical and crustal difference between the two faces.
The link could have gone straight to the Penn State news article Forbes was reporting on: http://news.psu.edu/story/3178...