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Homework Help: Temperature of Mars

  1. Nov 28, 2009 #1
    1. The problem statement, all variables and given/known data
    Estimate the temperature of Mars. Assume Mars acts as a perfect blackbody and the only heat input comes from the Sun (use necessary values from appendix)

    2. Relevant equations

    3. The attempt at a solution

    I was doing so well until I got to this question on my homework.
    I tried this: (pi)(rmars)2 / 4(pi)rsun2

    for the radius of mars my book says 6370 km and the sun 6.95e5 km
  2. jcsd
  3. Nov 28, 2009 #2


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    Thats just one small step in the answer.

    First think about what the question means:
    How much power does mars recv from the sun ?
    How much power must it emit (and why)
    Therefore what temperature must it be?
  4. Dec 1, 2009 #3
    We finally talked about this a little in class today, I think. The teacher put up an equation for radiation.

    Is this part of what I need to use to finish the question? I know what sigma is and e but I don't know what A is.
  5. Dec 1, 2009 #4


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    This is the power emitted by a surface of area A at temperature T

    Careful - what area of mars receives energy from the sun and what area emits energy into space?
  6. Dec 3, 2009 #5
    Thanks for your help, I finally got it
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