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Reflection and refraction: the same thing at the atomic level?

  1. Oct 9, 2015 #1
    I got cornered in a discussion on the internet... I am not sure if I am right or not (I thought I was when I started). If you guys here tell me I am wrong, I have no problem admitting if I am indeed wrong




    first... person 2 said "Refraction =/= reflection. The atmosphere is colorless because it does not reflect any light, regardless of refraction.".

    Does atmosphere really does not reflect any light? It seems to me that at atomic level, Rayleigh Scattering is reflection of light between atoms. Due to different medium, the APPARENT velocity of light is different, but between the atoms, it´s still the same old constant C. What changes is the lenght of the path light travels to get across the medium.

    Isn´t it?
     
  2. jcsd
  3. Oct 9, 2015 #2

    mfb

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    Not in the way solids can do that as coherent effect of the whole surface.
    "Speed of light in between atoms" is not well-defined for atom spacings smaller than the wavelength of light.

    The atmosphere scatters blue light more than red light. If you look close to the sun at sunset or sunrise, you'll see red. Does that make the atmosphere red?
     
  4. Oct 9, 2015 #3
    yes, I understand that... but that is when we think "as a whole". When we think about the atmosphere as atoms, aren´t the atoms in the atmosphere reflecting the light?



    no. But does seeing a red cup makes that cup red? As far as I understand, that cup is not red, it´s just reflecting more red light. From some angles and IF there is red light component falling unto it. If you shine a blue light unto it, it´won´t be red anymore. Also near the borders of the cup, it will reflect light differently, in a more cohesive way, so that you see highlights or reflections in other colors (like blue or white)
     
  5. Oct 9, 2015 #4
    The atmosphere as a whole reflects about 30% of the incoming light (from the sun).
    See "albedo".
     
  6. Oct 9, 2015 #5

    mfb

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    Solids are more than a collection of individual atoms. You cannot explain properties of solids by looking at isolated atoms.
    For the atmosphere, that works, sure.
    Well, "reflection" - it's not like a mirror. It scatters light, some of it leaves Earth without reaching the ground.
     
  7. Oct 9, 2015 #6
    Reflection is not limited to specular reflection. A piece of paper reflects light but is not a mirror.

    But I agree that reflection does not properly apply to atoms.
     
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