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Thread: How hot is dark matter?

  1. #1 How hot is dark matter? 
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    Dark matter can't radiate heat (i.e. no electromagnetic energy).


    1. Might it retain the original temperature at the moment of its creation?


    2. If temperature is directly related to pressure and both are inversely related to volume, then would cosmic expansion mean that dark matter is as cool as the cosmic microwave background radiation?


    3. Can the temperature of a given region of dark matter be inferred based its inferred volume and mass?


    4. Does the inability of dark matter to radiate heat imply that there can be no dark matter "black holes"?


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  3. #2  
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    I think your question implies that we know a great deal more about dark matter than we do.


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    All that is known so far is that there are things that are seeming to cause space to expand even in spite of gravitational pull, that we have not found a way to explain yet. They are called "darK" because we have not found a way to directly detect them. No emf, no temperature, no emanations that we can detect.

    A huge amount of new info is being brought to us about the larger Universe, by new huge telescopes trapping light from the past - but it is humans who are deciphering the info coming in and it is not like taking pictures of what your eyes can see, a lot of the pictures are time lapsed and infrared and ultraviolet and doctored so our eyes can view them. High tech photoshopping, you could say.
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  5. #4  
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    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
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  6. #5  
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    If Dark Matter were too hot, it would not get pulled into a galaxy and contribute to that galaxy's overall gravity. So, since the whole basis for us to believe it exists is that it is taking part in the gravity of galaxies, that tells us that at least a substantial portion of it must be moving slow enough to get into a stable orbit around a galactic center.

    How it got to be moving that slow is quite a mystery. If it were moving fast like everything else at the moment of the Big Bang, then it should have simply continued at that speed forever after. Either that, or we'd need a way for it to slow down by emitting gravity waves or some other kind of emission (since emitting EM is out of the question.)
    Some clocks are only right twice a day, but they are still right when they are right.
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  7. #6  
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    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    You posts seem to border on "trolling". I can't see you lasting long here. So how about some real science from you.
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    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    By "hot" are you inferring "really interesting to you?" If so, me too!
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  9. #8  
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    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    By "hot" are you inferring "really interesting to you?" If so, me too!
    I think Batman is a fly by nighter.
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    Quote Originally Posted by Robittybob1 View Post
    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    By "hot" are you inferring "really interesting to you?" If so, me too!
    I think Batman is a fly by nighter.
    Oh I see! Maybe using echolocation! Still, if dark matter were hot as in temperature hot, we could detect it, and even if we are not batty-bats, we could detect it with human sonar if it had a surface to bounce sound waves off of.
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  11. #10  
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    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Robittybob1 View Post
    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    By "hot" are you inferring "really interesting to you?" If so, me too!
    I think Batman is a fly by nighter.
    Oh I see! Maybe using echolocation! Still, if dark matter were hot as in temperature hot, we could detect it, and even if we are not batty-bats, we could detect it with human sonar if it had a surface to bounce sound waves off of.
    Sound waves??? Are you sure about that?
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  12. #11  
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    Quote Originally Posted by Robittybob1 View Post
    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Robittybob1 View Post
    Quote Originally Posted by Mayflow View Post
    Quote Originally Posted by Bat-man View Post
    dark matter is infinitely hot. it is what we make of it, thus infinite. in every way.
    By "hot" are you inferring "really interesting to you?" If so, me too!
    I think Batman is a fly by nighter.
    Oh I see! Maybe using echolocation! Still, if dark matter were hot as in temperature hot, we could detect it, and even if we are not batty-bats, we could detect it with human sonar if it had a surface to bounce sound waves off of.
    Sound waves??? Are you sure about that?
    Not completely, but it does seem that that is how bats "see" things.
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