• Question: Why do stars twinkle?

    Asked by beccawilko to Angus, Christian, Hannah, Laura, Simon on 25 Jun 2013.
    • Photo: Angus Ferraro

      Angus Ferraro answered on 25 Jun 2013:

      Stars twinkle because of the swirling motions of the air above us. As the light from stars passes through the atmosphere it gets bent (refracted) slightly, first one way, then the other, which causes the ‘twinkling’ effect. If you were in space, outside the atmosphere, the stars wouldn’t twinkle at all.

      If you have ever looked upwards at the Sun (or a light) while in a swimming pool, you will see the light seems to be ‘jiggling’ about because the water. The atmosphere makes the light from stars jiggle in the same way.

      So why doesn’t the Sun twinkle? Well, the Sun is much closer to the Earth than all the other stars. This means the ‘jiggling’ motions in the atmosphere are much smaller than the disc of the Sun, and we can’t make out the tiny jiggles.

    • Photo: Laura Roberts Artal

      Laura Roberts Artal answered on 25 Jun 2013:

      Thanks Angus! I didn’t know that. It’s great to learn something new!

    • Photo: Simon Holyoake

      Simon Holyoake answered on 26 Jun 2013:

      The name of this behaviour is ‘Scintillation’ and angus has explained it really well!

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