Quirks & Quarks

Do other planets in the solar system have orbital tilt and seasons?

All but Mercury have orbital tilt, and there are some long and extreme seasons on other planets

All but Mercury have orbital tilt, and there are some long and extreme seasons on other planets

An illustration of our Solar System (NASA)

This week's question comes to us from Doug Archer on Salt Spring Island in British Columbia.

He asks: Do any other planets in our Solar System have offset poles, thus giving them seasons?

Kaja Rotermund, a graduate student in the Physics Department at Dalhousie University in Halifax, explains that having offset poles, or magnetic poles that don't correspond to rotational poles, as Earth does, does not effect the seasons. What does create seasons is the tilt of a planet's rotational axis. All the planets in our Solar System do have such a tilt, with the exception of Mercury. 

Uranus for example has a 98 degree tilt, compared to Earth, which has a tilt of 23.5 degrees. The axis of rotation of Uranus is almost parallel to its orbital plane. Because it takes Uranus 84 years to orbit the Sun, each season last 21 years.

The shape of a planet's orbit around the Sun can also affect seasons. Earth's orbit is fairly circular, so it has little impact on seasons. The orbit of Mars is elliptical. When Mars is furthest from the Sun, it receives less radiation. This coincides with its northern Summer, which is more cooler and longer lasting than the southern Summer, which occurs when Mars is closest to the Sun.  

Written and produced by Mark Crawley

 


 

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