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How does cold travel?

  1. Feb 1, 2009 #1
    Does what we as humans consider "cold" travel through space like heat does? Could a planet have moons that are cold because the planet itself is cold? I know cold is really just air, but could it somehow travel from one astronomical body to another?
  2. jcsd
  3. Feb 1, 2009 #2
    Cold is just lack of heat. We only use the word cold to measure the temperature of things.
    Heat is a form of energy. Starting at 0kelvin and going till infinite or so. 0k = -273.15 celsius.
  4. Feb 1, 2009 #3
    well, heres the deal. i am a writer, and i have a new idea for a book, but in the book, a planet is constantly cold beyond all reason because of their "star" (actually a planet) is just a solid clump of ice 100 times the size of Jupiter. would it be possible for the cold to transfer from the ice block in the vacuum of space?
  5. Feb 1, 2009 #4
    How does the 'star' produce light?

    No, cold doesn't travel in the same way that heat does. However, heat wouldn't be coming from anywhere else, so your planet would definitely be cold. If somehow the planet heated up but the star didn't, then either the planet would cool down pretty quickly when it moved away (heat would be radiated into the cold of space and towards the cold star), or it would need to have a LOT of greenhouse gases in its atmosphere.

    So the star wouldn't 'give' the planet 'cold', but it would take its heat away instead (although chances are it wouldn't have any heat to speak of).
  6. Feb 1, 2009 #5
    If you are looking for a physical mechanism for a light emitting, cold thing removing energy from a orbiting planet you're going to struggle.

    If two astronomical bodies are seperated by vacuum, they can generally only send energy to each other. They can't take it.

    From the point of view of a story, I'd dispense with requiring a physical explanation and have the situation exist without explanation. If you want to use a physical sounding term that might be involved, may I suggest 'resonance'. You can blame everything on that.
  7. Feb 1, 2009 #6


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    It would help to think of cold as the ground state for everything. If you're not receiving energy, you're cold. In the absence of any significant energy source, the ground state is cold.
  8. Feb 1, 2009 #7
    Bear in mind that “cold” isn’t a form of energy; it is merely the absence thereof, so “cold” naturally exists in the absence of heat energy. "Cold" therefore, doesn’t radiate rather, that which is cold absorbs heat energy, so “cold” has no need to travel since heat energy provides the energy for its own transport. If you remove all sources of heat, objects begin to immediately cool down. This is why the shaded side of an object in the vacuum of space would otherwise be frigid when the energy from our Sun is merely blocked by an opaque object. This is just one of the reasons that many objects placed in orbit that must be protected from extreme cold are typically rotated to help regulate the object’s temperature. Of course, that which requires extreme cold is kept shaded from the Sun to make use of the extreme cold that naturally exists in the absence of an energy source (as when attempting to prevent liquid helium from boiling off before its time in satellites).
    Last edited: Feb 2, 2009
  9. Feb 1, 2009 #8


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    It's maybe a dark sucker ? :tongue2:
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