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What *would* the night sky look like if we could see the entire EM spectrum?

  1. Sep 18, 2011 #1
    Assuming, of course, that we simply rescaled our color perspectives so that longest wavelengths = red, shortest wavelengths = violet. Are there any such pictures?
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  3. Sep 18, 2011 #2


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    Not altogether unlike what we see in the visible spectrum. There is a bit more radiation at both ends, but, it does not make a dramatic difference.
  4. Sep 18, 2011 #3
  5. Sep 18, 2011 #4


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    You can no more conceive this than you can describe colour to a blind person. Any pictures we create of this would look the same to you as pictures that didn't include these wavelengths because you can't see them.

    Any pictures that show wavelengths like x-ray can only do so if they are shifted into the visible spectrum.
  6. Sep 18, 2011 #5
    But that is what the OP suggested...
  7. Sep 18, 2011 #6


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    My mistake. I read colour perception as meaning biologically changing rather than chaining the image.
  8. Sep 18, 2011 #7
    I actually dug around for a night-sky-average spectrum in absolute units over many decades of wavelength, but couldn't find one so I don't know. But I would bet it would peak in the visible just like the spectrum that our eyes detect does, because most radiation comes from stars that have an effective blackbody spectrum that peaks in the visible. You would get a lot more "blue" from UV up through x-rays (variety of sources), and also a lot more "red" from warm dust down to the cosmic microwave background, but plotted in units like Ergs/s/eV/Sr I would bet it still peaks in the visible.
  9. Sep 18, 2011 #8

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    I beg to differ. That what we see in different frequency domains is dramatically different from what we see in the visible spectrum is the driving impetus behind the many different kinds of telescopes astronomers have developed. Astronomers use telescopes that range from long wave radio up to gammas. If what we saw was more or less the same across the EM spectrum there would be little justification for this plethora of devices, some of which are very expensive.
  10. Sep 18, 2011 #9
    Whether it already exists or not: is there any reason to suspect the picture that the OP suggests can't actually be made? I think that would be a very interesting picture :)
  11. Sep 18, 2011 #10
    I don't think that was the question, at least that's not how I interpret it. Obviously things can look dramatically different in different energy bands, but if the emission levels in those more-exotic bands is low then a detector with a flat response would hardly notice.
  12. Sep 18, 2011 #11
    Well, one example of how different things could look, if you could see magnetic fields, Jupiter would look something like this.

    Though I should note they have the wrong moonphase in that image, given the direction of the sun implied by the magnetic field and the moon are almost perpendicular to each other.
  13. Sep 19, 2011 #12

    I basically mean something like this -- going from the real-life, current visible spectrum slice and expanding it to where the bold lines are instead. Most of the matter that we are used to seeing with color, on our planet, would appear greenish, but we'd be able to see everything else, too, outside of the 390 to 750 nm range. I'm wondering what that would look like, or what the night sky would look like. I am just trying to understand what would look different and how.
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