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The atomic number of molybdenum.
The angle in degrees for which a rainbow appears.
In 1965, mathematician Paul Cooper theorized that the fastest, most efficient way to travel across continents would be to bore a straight hollow tube directly through the Earth, evacuate it (remove the air), and then just fall through. The first half of the journey consists of free-fall acceleration, while the second half consists of an exactly equal deceleration. The time for such a journey works out to be 42 minutes. Remarkably, even if the tube does not pass through the exact center of the Earth, the time for a journey powered entirely by gravity always works out to be 42 minutes, as long as the tube remains friction-free. The same idea was proposed by Lewis Carroll in Sylvie and Bruno, volume 2, chapter 7, without calculation.
Originally posted by theresult