Disappearing Act

A puzzle by Joseph Horton, from MIT Technology Review, January-February 1999:

If the sun takes two minutes to set, what angle does it subtend from Earth?

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Half a degree. Earth rotates through 360 degrees every 24 hours, or 1 degree every 4 minutes. 01/27/2021 UPDATE: This is oversimplified — time to set depends on time of year (declination) and the observer’s latitude. The Review posted a correction in the May/June issue: “Peter Blicher notes that we are erroneously assuming the sun sets at a 90 degree angle to the horizontal.” Thanks, Chris and Martin.