The moon dances around the earth, completing its circle every 27.322 days.
Why can we earthlings only see one half of the moon? Over the millennia, the earth’s gravitation eventually made the moon slow its rotation around its axis. Now it matches the time that it takes to go around the earth. The dark side of the moon isn’t really dark, just invisible to us from earth.
Speaking of rotation, the moon’s energy that causes tides is slowing down earth’s rotation by a whopping 1.5 milliseconds a century.
The moon is using rotational energy to get away from the earth. It started out about 14,000 miles away when it was formed, and is now more than 280,000 miles away. And it’s making good progress: every year its orbit gets larger by about 3.8 centimeters. At that rate, it will only take, oh, 50 billion years or so before it breaks free.
Maybe after it escapes the earth's hold, the moon will find a new dance partner.
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