Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Locked in synchronous rotation, the Moon always presents its well-known near side to Earth. But from lunar orbit, Apollo astronauts also grew to know the Moon's far side. Surprisingly, the rough and battered surface of the far side looks very different from the near side which is covered with smooth dark lunar maria . The likely explanation is that the far side crust is thicker, making it harder for molten material from the interior to flow to the surface and form the smooth maria.
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