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Do types of electro magnetic radiation exist that we can not detect?

  1. Apr 25, 2010 #1
    Basically what im wondering is if types of electro magnetic radiation exist that are on a wavelenght or frequency that we can't detect with our technology?

    My follow up question would be is it possible blackholes give off that type of radiation? I suspect the answer I'll get from most people is nothing can be given off by blackholes and to that I would say perhaps it works like hawking radiation.
  2. jcsd
  3. Apr 25, 2010 #2
    As of this posting, no undetectable electromagnetic radiation has been detected.
  4. Apr 25, 2010 #3
  5. Apr 26, 2010 #4


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    From what I have read, generally speaking, the higher energy electromagnetic radiation interacts much less than lower energy radiation. Case in point are x-rays which will readily pass through our meatbag bodies with little scattering (outside of highly dense things like bones and errant surgical tools). So very very high energy radiation may be very difficult to detect due to the low incidence of interaction. However, generally when such high energy waves do interact, they do so in a rather spectacular fashion. Case in point, when you have yourself many many x-rays your DNA seems to have little hissy fits. Another example are the cosmic rays that interact in our atmosphere, they generally decompose into various particles like you would see in a particle accelerator. So while we may have a harder time detecting the radiation directly, we probably can easily perceive the consequences of their interaction with particles.
  6. Apr 26, 2010 #5
    So is that what thouse underground experiments looking for dark energy do?
  7. Apr 26, 2010 #6
    something to do with cosmic neutrinos and flavors, sounds like an ice cream parlor, hey! is that where the research money goes? new flavors of desert :D
  8. Apr 26, 2010 #7


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    Yeah, the underground experiments that I know of, apart from the various particle accelerators that are put underground, are for neutrino detections. I think I recall that Fermi Lab has an experiment in a Minnesota mine that detects neutrinos from their accelerator. That is, the accelerator emits neutrinos in Batavia, IL and they have plates of a battleship's worth of iron hundreds of miles away that the neutrinos hit and interact with.
  9. Apr 27, 2010 #8


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    1) Just so we're clear, neutrinos are not electromagnetic radiation. Different beast entirely.

    2) There are no different types of electromagnetic radiation. All distinctions (x-ray, infrared, visible, gamma ray, radio, UV) are merely arbitrary distinctions created by humans. It would be like giving different names to a ball depending on how fast we throw it. Obviously, the ball is the same thing, just with a different amount of energy. EMR is analogous.

    That said, like Bron2bwire mentions certain types of EMR are easier or harder for us to observe. So sure, perhaps we cannot detect emr with a wavelength of 1 light year. This does not imply it does not exist, nor does it imply that there is anything special about it.

    As far as black holes are concerned, we can expect a stellar mass black hole to emit radiation with a wavelength on the scale of 10's of kilometers. For a SMBH, the characteristic wavelength of radiation is on the order of several AU. (Note this is hawking radiation, not radiation from an accretion disk.)
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