How long are the seasons on Mars?

25 May 2008



How long are the seasons on Mars?


Seasons happen here on Earth because the planet is tilted on its axis by about 23.5º. This means that, during part of its journey around the Sun, the Earth's northern hemisphere receives more solar energy than the southern hemisphere; during the other half of the year, the reverse is true. This difference in solar input is what leads to the changes in average temperature in those hemispheres that we refer to as "seasons".

Compared with the other rocky planets, the seasons on Mars are the most similar to those of Earth. This is because, like Earth, Mars is also tilted on its axis and by a very similar amount: 25º to the vertical. This produces temperature changes that alter like those on Earth across the year as Mars orbits the Sun.

But a year on Mars - lasting 687 Earth days - is considerably longer than an Earth year (365 days) because Mars orbits about 50% farther again from the Sun than Earth, so it has a greater distance to travel. The shape of Mars' orbit is also a bit more elliptical than the Earth, so the seasons are not all the same length. "Spring" on Mars lasts 7 months; "Summer" goes on for 6 months; "Autumn" lasts a touch over 5 months, and "Winter" is 4 months long.

The "Summer" temperatures on Mars are definitely nothing to write home about though and compared with Earth, where 50ºC is encountered in some places, the top temperature on Mars is usually barely above zero... Some "Summer" huh?


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