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Suns heat to earth

  1. Nov 26, 2015 #1
    Is what heats the earth the energy turned into heat from the sun, or the light hitting the earth from the sun. how does light heat anything if it has such small mass how can it excite particles.

    I assume that it would be the light hitting the earth heating it for obvious reasons, like seasons. but then what happens to all the thermal energy produced by the sun. would the thermal energy need a median to move through. is that why the sun is so hot to begin with there because there is nothing really for the heat to move through except low density hydrogen (space) to lose heat to, but theres not much of that around. Is it because theres not enough of a median for heat to travel to use in any noticeable amount?
     
  2. jcsd
  3. Nov 26, 2015 #2
    Yes, energy as radiation arriving from the Sun does heat up the Earth.
    Photons at various energies are absorbed by the atoms that make up the Earth, which makes them more energetic atoms (hotter).
     
    Last edited: Nov 26, 2015
  4. Nov 26, 2015 #3

    SteamKing

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    Not all of the radiation coming from the sun is in the form of visible light.

    There's a whole spectrum of radiation stretching from x-rays to ultraviolet to visible light to infrared to radio waves coming from the sun.

    It's all electromagnetic radiation which doesn't need a medium in which to propagate. A vacuum (or almost one) suffices quite adequately.
     
  5. Nov 26, 2015 #4
    Radiation is energy, heat is also energy all forms of matter can emit and absorb radiation. Emission and absorption of radiation depend upon the temperature of that matter, the matter at higher temp. performs more emission than absorption and vice-versa. Sun is at very high temperature, i.e. in billions deg. Centigrade, this so because Sun is having both nuclear fission and fusion, sun is just that big cloud of helium and hydrogen that are continuously performing fission and fusion. Thus it release large amounts of radiation in form of heat and light, just like a camp fire.
    Being at exactly the right distance from sun is what made life possible on earth, we take a lot of things for granted. Instead we should think that our existence is such an amazing coincidence that has happened out of Billions of Trillions of possibilities. Our solar system will eat itself and we'll get destroyed but we are trying to be a intersteller species and one day maybe inter galactic.
     
  6. Nov 26, 2015 #5

    DrClaude

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    Note also that there are three types of heat transfer: conduction, convection, and radiation. Contact with some form of matter is not necessary in the case of radiation.
     
  7. Nov 26, 2015 #6

    Drakkith

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    Light is an electromagnetic wave and is able to exert a force on charged particles, performing work on them (and energy is essentially the ability for something to perform work, so we say that light 'carries' energy with it). When it interacts with atoms and molecules it makes them vibrate back and forth more and more, which heats them up.

    The thermal energy of the Sun is converted into EM radiation and radiated out into space. This lost thermal energy is replenished by fusion in the Sun's core. The surface of the Sun is as hot as it is because of the poor thermal conductivity of space (essentially zero). This means that the only method available for the Sun to get rid of its thermal energy is to be hot enough so that the energy given off as radiation is equal to the energy generated by fusion.
     
  8. Nov 26, 2015 #7

    sophiecentaur

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    Light has no mass. A Photon has Energy and momentum but no mass. It excites particles by transferring its energy, either to individual atoms or to the whole structure.
     
  9. Nov 26, 2015 #8
    If light has no mass, then why is there gravitional lensing. the light bending to the influence of gravity? and only things with mass can interact with gravity ? isn't that true?
     
  10. Nov 26, 2015 #9

    sophiecentaur

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  11. Nov 26, 2015 #10
    so how can light interact with gravity then?
     
  12. Nov 26, 2015 #11

    sophiecentaur

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    General relativity and what mass does to the space around it. The light still travels in a straight line - as far as it is concerned, because that is the shortest distance when the space has been interfered with by a massive object.
     
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