Dark matter

Discussion in 'Astronomy, Exobiology, & Cosmology' started by arauca, Feb 7, 2013.

  1. arauca Banned Banned

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    What is dark matter . Do we call it dark matter is it because it does not emit light nor reflects light ? Example as if there would be a carbon black massive object , that object could not be seen with a telescope ?
     
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  3. origin Heading towards oblivion Valued Senior Member

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    That is essentially right.

    No, that is not accurate, we could detect it because it would emit infrared for instance. Dark matter does not appear to interact with light or EM at ALL.
     
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  5. arauca Banned Banned

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    In space the body is cold , the emission is function of temperature . I assume we have not sent any of our own light sources to experience interaction or reflection.
    Again it the source ( dark matter ) is very weak , perhaps our sensors are not sensitive enough ?
     
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  7. origin Heading towards oblivion Valued Senior Member

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    That possiblity was of course considered and did not pan out. Due to the amount of dark matter that is theorized there would be plenty of infrared to detect if the dark matter interacted with EM radiation.

    Here is a link on IR and asteroids
     
  8. arauca Banned Banned

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    If I read correctly the limit of object in detection is 70 Kalvin below this temperature apparently there is no emission
     
  9. AlphaNumeric Fully ionized Registered Senior Member

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    If the temperature of an object is above absolute zero, ie 0 K or -273C (I'm British, we don't use Fahrenheit), then it will emit thermal radiation. And even if you had an object which was 0K it would still absorb light which falls on it and thus be visible because of its silhouette plus absorbing energy would raise its temperature.

    Dark matter isn't black, it is transparent.
     
  10. arauca Banned Banned

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    Ok let try to understand : let say hypothetically the dark matter is made out of quartz ( transparent ) the quartz ( dark matter ) is at 60K ( limit of detection 70 K ) I should not be able to detect . do you agree ?
     
  11. mathman Valued Senior Member

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    Dark matter doesn't clump. It is unaffected by electromagnetic force, which is what hold ordinary matter together. Current theories of dark matter describe it to consist of unknown subatomic particles.
     
  12. arauca Banned Banned

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    With this statement you are reinforcing my believe in God
    Putting that on a side what is the amount of mass or whatever of dark matter in our universe ?
     
  13. AlphaNumeric Fully ionized Registered Senior Member

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    Forget the 70K thing, it is completely wrong. Absolute zero practically defined as the temperature at which zero thermal emissions occur. Anything above that and thermal emissions occur. Sure, 70K is bloody cold to us, our bodies are at about 310K but 70K is very hot compared to space. An object sitting in space, bathed in the cosmic microwave background, will stablise its temperature at 2.7K. That 2.7K is still hot enough for WMAP and Planck telescopes to detect and examine, it is how we construct these pictures. If 70K were the cut off those pictures would be completely black.

    I used 'transparent' to illustrate that light isn't interacted with. Quartz still interacts with light, it just happens to leave alone most light of a particular frequency (visible light). Dark matter doesn't affect light at all other than via gravity. Glass is transparent to visible light but still interacts with light in general, the electrons and nuclei affect light. Dark matter simply doesn't have any impact, there are no charged particles in dark matter. Quartz at 60K is easy to detect. It would give off thermal emissions and although it might be mostly transparent to visible light it would block things like x ray, just as glass lets visible light through but blocks infra red or how the atmosphere lets through visible light but blocks gamma and x rays. Normal materials, transparent or not, interact with light. Transparent materials just don't do it too much for visible light. Light, of any frequency, doesn't even know dark matter is there other than by its gravitational field.

    Then you have absolutely no idea about the scientific method, you have a terrible standard of evidence and you're simply looking for things to reenforce your preexisting assumptions, ie leading the evidence rather than being led by the evidence. Nothing he said has in any way a justification for believing in a deity. Stop being blinded by unjustified beliefs.

    Visible, normal matter makes up 4% of the total mass/energy of the visible universe. Dark matter makes up about another 20%. The rest is dark energy.
     
  14. gabana Registered Member

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    The dark matter is likely to be the weakly interacting axions and/or the constantly appearing and disappearing virtual particle pairs induced by changing gravitational fields.
     
  15. arauca Banned Banned

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    At what rate doe it comes and goes ?
     
  16. spidergoat pubic diorama Valued Senior Member

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    Let's face it, everything reinforces your believe in God, especially not understanding things. Because God is the ultimate lazy person's explanation for anything.
     
  17. Scott Myers Newbie Registered Senior Member

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    The current model is 83% Dark Matter.
     
  18. Crunchy Cat F-in' *meow* baby!!! Valued Senior Member

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    Some kind of matter that doesn't interact with anything (even itself) with the exception of applying gravitational force. I'll speculate it's a WIMP of some kind.

    As Alpha pointed out, we call it dark because it's transparent.

    If there were a big enough light source behind or near a carbon black massive object then we could detect it with a regular telescope.
     
  19. arauca Banned Banned

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    Why do you have to think that way. God is my spiritual part of life. I live in a material life and that is a part of me . Since we don't know how every thing started , I look for physical explanation about the beginning , but we don't have them yet , we have some theory that explain some part and part have a flimsy explanation , let say dark matter, there are other physicist with their theory that dark matter is not required . Should I join the band wagon , no, I rather sit on the fence.
    I have seen pictures from astronomy , and some of the explanation for irregular shape of galaxy , for this skeptic are not convincing, yes they show some irregularity but is their explanation correct , I don't know , perhaps if they come up in the future with different explanation .
    I thy to grow both ways in a dualistic way .(Particle and wave )
     
  20. spidergoat pubic diorama Valued Senior Member

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    Science is flimsy, but the Bible is not? Why the double standard?
     
  21. arauca Banned Banned

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    That is a hell of a lot of matter if all the galaxy and its content is only the difference ,
    By the way what method or technique was used to determine the whole mass of matter ?
     
  22. arauca Banned Banned

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    So if you have very fine carbon black and you have a temperature of 2.7 K there would not be any emission to capture signal with infrared telescope ?
     
  23. Crunchy Cat F-in' *meow* baby!!! Valued Senior Member

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    No idea; however, you could still notice it in the visible light spectrum.
     

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