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2 articles on this topic.
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Dig a straight tunnel between any two points on Earth, pump out the air, and let gravity supply the propulsion. The trip takes 42 minutes, and the remarkable part is that it takes 42 minutes no matter which two cities you pick.
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The Earth stays in orbit because of its angular momentum. Take that away, stopping the planet dead in its tracks, and how long until it reaches the Sun? Working out the answer turns up an unexpected appearance by pi.