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Sun rays

  1. Dec 6, 2013 #1
    Why sun rays are not considerably hot when reaching earth..? is there any specific reason for the sun rays to lose its potential(temperature) as it travels a long distance in space where there is no forces to contain it nor disturb its motion. Does space have property too,because as far as i know space is a VOID
  2. jcsd
  3. Dec 6, 2013 #2

    Simon Bridge

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    The concept of temperature does not apply to individual rays.

    The heat you experience off sunlight comes from the density of the rays (we'd say "flux") rather than from individual rays. Since the rays diverge in all directions, the density of the rays (the number that pass through each square meter) decreases with distance from the sun. At double the distance, the number of rays is quartered.

    But we need to be careful - the word "ray" has a specific definition in science and I am not sure that is the definition you are using.

    I don't know what you mean by "does space have property" ... and I'm not sure that "void" is a precise term ...

    Are you asking about the classical vacuum?

    There is a sense in which we can talk about the properties of empty space - you have been doing that as soon as you say it is empty ... which suggests it has the property of volume. Things can travel in it - so it has to have an extent and a geometry ... we can discover the geometry by tracing trajectories just like we discover the geometry of the surface of the Earth. It's a big subject ... so the short answer is "yes: it makes sense to talk about space having properties".
  4. Dec 6, 2013 #3
    Thank you san for clearing my doubt. I have seen in a film featuring a scene when a astronomer opens his space helmet off his head his head getting shattered in to tiny pieces. Does that makes sense or is that what really happens?
  5. Dec 6, 2013 #4

    Simon Bridge

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    No. The moviemakers were using artistic license. You'll see other movies where other things happen.

    This is a different topic - you can google for what happens when the body is exposed to hard vacuum.
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