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今日のお品書き(2015-03-31)

startswithabang:

Astroquizzical: Do all planets rotate in orbit around their stars?

“Do all planets rotate as they go around their stars? Do they all rotate in the same direction (e.g. clockwise or anticlockwise?) Or does it just depend on what started them rotating in the first place?”

When you think about our world and our place in the Solar System, you very likely think about Earth, spinning on its axis, with the Moon orbiting around it, and with the entire Earth-Moon system orbiting the Sun. In fact, all of it — the Earth spinning on its axis, the Moon revolving around Earth, the Earth revolving around the Sun, and even the Sun spinning on its own axis — spins in the same direction: counterclockwise, as viewed from looking “down” on the Earth’s north pole. Is this true for all planets in all solar systems? The answer turns out to be “mostly,” but there are some incredibly interesting exceptions.

A great column by Jillian Scudder.