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from the comes-in-colors-everywhere dept.
In 2001, some physicists put their heads together and asked: “What is the color of the Universe?”
By this they meant what color would an observer see, “if they had the Universe in a box, and could see all the light at once.”
“And,” they added, as if that question was too simple, “it wasn't moving.” They added this bit because, because of the Doppler effect, stars that are receding from Earth are redshifted – i.e. they appear redder than if they weren’t moving, relative to us.
Even though, as New Scientist observed, the question might seem about as useful as “the ‘answer’ to life, the Universe and everything given in the Hitchhikers Guide to the Galaxy - 42,” the astronomers knew the spectral analysis would help them trace the history of star formation. So they forged ahead with the calculations and, in January 2002, captured the public’s attention when they announced their result.
“In space no one can hear you scream, which is probably a good thing,” the Guardian wrote in their coverage, “as scientists have discovered that the universe is a shade of turquoise.”
The Guardian’s reporter might have been glib, but many others embraced the color. The real problem was, the universe isn’t turquoise. The scientists had gotten it wrong.
http://priceonomics.com/what-is-the-average-color-of-the-universe/
(Score: 2) by maxwell demon on Thursday January 29 2015, @09:14PM
Yes, of course. BTW, no need for a link, I'm physicist.
Wrong. EM radiation is generally a mix of many different wavelengths. EM radiation that consists of a single wavelength is called "monochromatic".
More exactly, 400 to 750 nm.
No. You can give a spectrum which consists of many different wavelengths (generally, all of the visible wavelengths are there, although there are exceptions). However the spectrum is not the same as the colour since different spectra correspond to the same colour (this is why you can mix almost all colours with only three base colours — in other words, this is why your colour monitor works). The only exception are the spectral colours (that is the colours of monochromatic light). Those cannot be mixed from other colours (which BTW also means that your monitor cannot properly display them).
It must be an extraordinarily bad physics course that doesn't teach spectra.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by NotSanguine on Thursday January 29 2015, @09:44PM
All EM radiation has a wavelength.
Wrong. EM radiation is generally a mix of many different wavelengths. EM radiation that consists of a single wavelength is called "monochromatic".
I'm going to assume you misunderstood me rather than being deliberately obtuse. Let me be more precise. Each quanta (photon) of EM radiation has a specific wavelength.
"Visible" (to us at least) light has wavelengths in the 4000-7000 angstrom range.
More exactly, 400 to 750 nm.
And so it is.
If you can say with any sort of confidence that the universe is "beige" then you can be more exact by expressing that in terms of wavelength.
No. You can give a spectrum which consists of many different wavelengths (generally, all of the visible wavelengths are there, although there are exceptions). However the spectrum is not the same as the colour since different spectra correspond to the same colour (this is why you can mix almost all colours with only three base colours — in other words, this is why your colour monitor works). The only exception are the spectral colours (that is the colours of monochromatic light). Those cannot be mixed from other colours (which BTW also means that your monitor cannot properly display them).
Apparently, you didn't even bother to read the *headline* of TFS: "What is the Average Color of the Universe?" TFA says:
"So what is the average color? i.e. the color an observer would see if they had the Universe in a box, and could see all the light at once (and it wasn't moving, for a real observer on earth, the further away a galaxy from us the more it is redshifted. We have de-redshifted all our light before combining)."
What is more, TFA provides the spectra as well if you're interested in anything other than arguing irrelevancies while trying to make yourself feel more important.
This is high school (middle school?) physics, friend.
It must be an extraordinarily bad physics course that doesn't teach spectra.
I can't speak for your school. Mine certainly did.
So. To be non-judgemental, I'll assume you just misunderstood rather than being deliberately obtuse.
No, no, you're not thinking; you're just being logical. --Niels Bohr