"Most planets in our solar systems have a tilt. Mercury is the only one that has nearly no tilt at 2 degrees. It’s thought that early in earth’s formation over 4 billion years ago, a planet the size of Mars, which we now call Theia, crashed into earth and knocked it off its kilter. In doing so, some of the material from the two planets was thrown off and began to orbit the earth. And over time it coalesced into the moon. This impact also created a permanent tilt in earth’s rotation."
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