Teaching Modern Physics - QuarkNet - Fermilab

Modern Physics
The Ultraviolet Catastrophe!
1. As Ms. Nicks turns up and down the lamp, how does the spectrum change? Describe what
happens.
2. Go to the website http://skyserver.sdss.org/. The Sloan Digital Sky Survey is an attempt to
make a scientific map of the night sky in the Northern Hemisphere. One thing they have done
is to take spectra of several stars and galaxies. To locate these, we will use their Navigate
tool. Under Skyserver Tools, click Visual Tools, then Navigate. A pretty picture of some
galaxies should come up in a new window. To see which objects the Sloan scientists have
actually taken spectra of, click “SpecObjs” under Drawing options. Now those galaxies and
stars for which they have spectra will have a red box around them. The galaxy in the center is
such a galaxy.
Click on the red box, and a small picture of the galaxy and some numbers will come up on
the right-hand side of the screen. If you click on Explore over on the right, the data about this
galaxy will come up in a new window, called the Object Explorer window. You can look at
the spectrum if you scroll down a bit. If you click on the spectrum, it will open up to a picture
you can actually see. Sketch this spectrum, and indicate what overall wavelength you think
the peak of this spectrum is (the peak of the overall trend, not the tiny little peaks and
valleys).
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