• Question: why is space colder than earth even though it is closer to the sun????????

    Asked by bandd to Charlie, Eoin, Jemma, Julian, Steve on 19 Mar 2011.
    • Photo: Julian Rayner

      Julian Rayner answered on 18 Mar 2011:

      Hi bandd. Not an astrophysicist, but I think it is a misnomer that space is cold – there is just less matter to heat up, unlike on earth where there is lots of matter. Charlie is the guy to ask though, he is the one in the astronaut suit…

    • Photo: Jemma Ransom

      Jemma Ransom answered on 18 Mar 2011:

      Not really my area of expertise I’m afraid. I suspect (although check with Charlie) that because there is very little matter in space, and heat is really just a measure of how fast things are moving (when you heat molecules up you give them energy, so they move faster) that there isn’t enough matter in space to transmit heat effectively over long distances.

    • Photo: Eoin Lettice

      Eoin Lettice answered on 18 Mar 2011:

      Hi bandd,
      I’m not 100% on this one but since space is a vacuum (that means there is little or nothing in it) there is nothing to conduct that heat.

      Eoin

    • Photo: Stephen Moss

      Stephen Moss answered on 19 Mar 2011:

      Hi bandd

      I’m no astrophysicist but I think we feel warmth when air molecules bump together. If there are no molecules, like in space, then there is nothing to absorb the suns energy and radiate it to other things. But I’m sure that even space must start to feel hot once you get close enough to the sun?

    • Photo: Charlie Ryan

      Charlie Ryan answered on 19 Mar 2011:

      hello space isn’t necessary closely to the sun – there’s lots of space out there!
      Its a little difficult to say what the temperature of space is – temperature is a measurement of the movement of molecules, and in the vacuum of outer space there aren’t many molecules around! The ‘heat’ you would feel from space is from the energy of the suns photons hitting you. This can be a serious problem for astronauts, and is why spacesuits are white – to reflect most of the solar radiation and stop the astronaut overheating.
      It is this radiation from the sun – these whizzing photons – that make you feel warm. Especially infra red photon radiation whose energy is very well absorbed by the molecules in your body. So as you move closer to the sun you feel warmer, as more photons hit you. Simple really!
      i think that’s right – any further Q’s please ask!

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