• Question: paul, i'm voting for you because you have answered all of my questions really well and thankyou (: i now know a lot more than i ever did!! i have 1 more question for you: if the sky is supposedly blue, and space is supposedly black, then where does that blue stop and the black start? and what is it called? thankyou for eveything (:

    Asked by eleanorbeedles to Paul, Lily, Mark, Sarah on 23 Jun 2010 in Categories: .
    • Photo: Mark Roberts

      Mark Roberts answered on 23 Jun 2010:

      You’re not voting for me then 🙁

      That is because the atmosphere makes the sky blue as the way it interacts with the sun’s light so I guess when you’re in the atmosphere is the answer.

    • Photo: Paul Roche

      Paul Roche answered on 23 Jun 2010:

      Wow, that’s a tricky question….

      OK, so we see the sky as blue when we are on the ground, but as you travel up (say in a plane), it will start to get a darker blue – if you went really high (tens of km) it would get black, and you’d see stars – this is what can be seen from very high altitude spyplanes. So the answer is that there isn’t really a point where the blue stops and the black starts – they sort of gradually fade together.

      The atmosphere is what makes our sky look blue (as it scatters the white light from the Sun) – so if we could remove the atmosphere, the sky would look black (with a very bright Sun in it – probably no stars as they would be too faint compared to the Sun) – so the higher up you get, the less air is above you, and the less blue the sky looks.

      Technically, space is an altitude of 100km high.

      p.s. thanks for voting for me!

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