• Question: what is an aurora? what is an aurora borealis?

    Asked by Isla to Lisa on 5 Mar 2018.
    • Photo: Lisa Baddeley

      Lisa Baddeley answered on 5 Mar 2018:

      Hi Isla
      An aurora is light emitted by atoms and molecules in the Earth’s upper atmosphere.
      The aurora happens at between 120km and 250km above the Earth’s surface. (In comparison, an airoplane travels at 10km above the Earth’s surface).
      It happens when small particles from the Sun (mainly electrons and protons) collide with nitrogen and oxygen atoms and molecules in the Earth’s atmosphere. When they collide the nitrogen and oxygen get more energy and they don’t want to have this energy. To get rid of it they emit a photon of light. The colour of the light will depend on whether it’s oxygen or nitrogen – you have green and red aurora with oxygen and blue aurora with nitrogen.
      An aurora borealis is the name given to the aurora which happen in the northern hemisphere above the Arctic. The aurora australis is the name given to the aurora which happen in the southern hemisphere over the Antarctic.
      I hope this answers your questions. 🙂

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