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Dark matter, what do we need to have here?

  1. Aug 7, 2015 #1
    Some times I think space and Matter most to be different on others places and maybe equations need to be fit, but to find dark matter, what do we need to have here?
  2. jcsd
  3. Aug 7, 2015 #2


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    Ok, I apologize for this. It seems like English is not your first language. And if I had to work in any language besides English I am pretty sure I would starve to death. So I am sensitive to criticism of language.

    But I cannot figure out what you are asking. Can you ask it a different way?
  4. Aug 7, 2015 #3
    I think he's asking what are the known requirements for dark matter that an equation must satistfy:
    Must interact with gravity
    Must not interact with electromagnetism
    Must be warm
    Must not have friction with itself

    Most research I've seen is more concerned about what dark matter isn't. With very little information, it's easier to determine what something isn't than what it is: It's not black holes, it's not neutrinos...
  5. Aug 7, 2015 #4
    I am Sorry, if on the galaxies there are dark matter , how we going to see dark matter here on earth?
  6. Aug 7, 2015 #5
    on this moment, are there any form the dark matter here on earth or any evidence here on earth?
  7. Aug 7, 2015 #6
    or just we see effects on galaxies, because we have the standard model with particles, are there any prediction about dark matter?
  8. Aug 7, 2015 #7


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    Dark matter is usually thought of as microscopic particles that doesn't interact with anything, except through gravity. Presumably there is plenty of dark matter around, but it can't be detected locally (so far).
  9. Aug 7, 2015 #8
    So , do we not have the sensors to detect dark matter? or do we not have the way to detect it? are there any equation or idea what connect dark matter with standard model or particles here?
  10. Aug 7, 2015 #9
    Presumably yes, there should be dark matter floating around the earth and in the solar system. But because we don't know what it is, we can't really detect it. We know it interacts with gravity, but gravity is weak, there is no way to detect a single particle from just its gravity. Dark matter would also be very diffuse. There has been research on how dark matter interacts with itself and matter, and it doesn't really at all, so it never forms clumps like matter does. That's a problem since in space we can only see big things. There is probably more dark matter in our solar system as their is matter, but it's spread out over the entire solar system where as matter is concentrated into a handful of really large objects.
  11. Aug 7, 2015 #10
    Dark matter's properties are not known so it can't be detected. No, it does not fit in the standard model. We can only detect the affects it causes: light bending around it, and extra gravity in galaxies.

    Dark matter may end up being a whole myriad of different things. There is no reason to believe that dark matter is all made of the same stuff.
  12. Aug 7, 2015 #11
    can affect the way how we move, speed, gravity or matter we have here?
  13. Aug 7, 2015 #12


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    We have three ways of observing very distant matter:
    1) If it is made up something that interacts electromagnetically, then we use telescopes to detect the light (radio wave, ultra-violet, infra-red, X-rays, or whatever - these are all forms of electromagnetic radiation) that it emits or absorbs.
    2) If it interacts through the strong or weak nuclear force, we can detect the various products of those interactions. An example would be neutrino bursts from deep inside a supernova.
    3) If it has mass, its gravity will affect nearby bodies, and we can observe these effects.

    So if we see #3, gravitational effects, without #1 or #2, we know we're looking at something that has mass but is not interacting electromagnetically or through the nuclear forces. And that's what we see, so in that sense we've already "found" dark matter. Of course, that's not the same thing as knowing what it is.

    However, the #3 technique only works for astronomical-scale objects, so we can't use it to find dark matter right here on earth.
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