is created by David Witten, a mathematics and computer science student at Vanderbilt University. For more information, see the "About" page.

Lengths of days and years of the planets


Years are pretty straightforward- they go in order of their distance to the sun. So, the nth planet has the nth shortest year.

Mercury: 87.97 earth days
Venus: 224.7 earth days
Earth: 365.25 earth days
Mars: 686.98 earth days
Jupiter: 4332.82 earth days
Saturn: 10755.7 earth days
Uranus: 30687.15 earth days
Neptune: 60190.03 earth days


Days are really different, and it is less correlative.

(Days are in earth days)

Mercury: 58 days and 15 hrs (7)
Venus: 243 days (8)
Earth: 1 day (5)
Mars: 25 hours (6)
Jupiter: 9.9 hours (1)
Saturn: 10.6 hours (2)
Uranus: 17.25 hours (4)
Neptune 16.1 hours (3) 


David Witten


How did Eratosthenes determine the circumference of the Earth?