How long is a year on Mars?
Short answer: 687 Earth days.
Long answer: Mars is farther from the Sun than Earth. Because planets take longer to orbit the Sun the farther they are from it, this means that one Mars orbit (i.e. one year on Mars) will be longer than one Earth orbit (one year on Earth).
Earth orbits the Sun every 365.25 days. Mars takes 686.971 Earth days to orbit the Sun, making its year about twice as long as a year on Earth.
See also: NASA video about years on Mars
Above: The seasons on Mars.
Image credit: NASA/JPL-Caltech.
Trivia
- Mars has seasons like Earth does, but becuase Mars has an eccentric orbit, its seasons are not of equal length.
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