• Question: how can you only see stars at night

    Asked by to Andrei, Ekbal, Gemma, Helen, Ruth on 17 Jun 2014. This question was also asked by .
    • Photo: Ekbal Hussain

      Ekbal Hussain answered on 17 Jun 2014:

      Hi!

      People have known for a long time that if you have two light sources with the same brightness, like two candles, and have them at different distances to you then the one closest to you will appear brighter.

      This is because the light from the one further away has to travel through a lot more stuff to finally get to your eyes. All this stuff (air, dust, smoke and other things like that) will make a lot of the light particles bounce off away from your eyes. So your eyes see a lot less of the actual light that leaves the candle further away from you.

      The same ideas work in space. The closest star to our planet is our sun, which is 10 million times closer than the next star called Proxima Centauri.

      So during the day time, the light from the sun completely swamps all other light coming from the stars. The stars are still there, we just can’t see them. Only at night time when the sun’s light is no longer around can we see the little light coming from those distant stars.

      Ekbal

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