• Question: why does earth have seasons?

    Asked by chloelou98 to Cesar, Emily, Jamie, Kate, Philippa on 21 Jun 2011.
    • Photo: Cesar Lopez-Monsalvo

      Cesar Lopez-Monsalvo answered on 16 Jun 2011:

      Nice one!

      Some people believe that because the orbit of the planet is an ellipse and not a circle, it must be hotter when we are closer to the sun than when we are further away. The truth is that this ellipse is so close to be a circle that it does not make much of a difference in terms of seasons. What actually matters is that the planet’s axis of rotation is inclined with respect to its orbit. That is why when the north side of the earth (we are there) is facing towards the sun, days last longer and they also seem hotter, whereas in Argentina or Australia days are shorter and are generally colder at the same time. Summer in the northern hemisphere is actually winter in the southern.

      If you want a more visual answer, Professor Brian Cox explained this nicely in wonders of the solar system.

    • Photo: Emily Robinson

      Emily Robinson answered on 17 Jun 2011:

      Great answer! I love watching programmes about this subject as I don’t know much about it.

    • Photo: Philippa Demonte

      Philippa Demonte answered on 19 Jun 2011:

      @chloelou98 Not all countries have 4 seasons in a year like we do in the UK. Those on the Equator have relatively consistent weather* and hours of sunlight all year round compared to countries further north or south of the equator.

      * except those that have a rainy season, like India, but that’s to do with the flow of hot and cold air over mountain ranges.

    • Photo: Kate Clancy

      Kate Clancy answered on 21 Jun 2011:

      Sometimes I think it would be nice to live in a part of the world without seasons… as long as it was always warm. In San Francisco, on the west coast of the USA, the weather is usually 70 degrees F (21 degrees C) year round. I think I’d like it just a little warmer and then I would be perfectly happy.

      The summers here in the midwest can be very hot — today it’s only 89 (32 Celsius), but last week it was 101 (38 Celsius)!