Evidence of Dark Matter Discovered

Stan Hart, NOAO RET
Based on a Solicited Contribution from David Wittman

Classroom Connection

A Simple Experiment

Get a pair of binoculars and tape a small piece of paper over one of the eyepieces you look through so you can only see through one side of the binoculars. You'll also need a paper tube from a roll of toilet paper. Go out on a night when you can see a lot of stars. If you live in a big city you may have to get away from city lights to see very many stars. Look at the stars through the paper tube. Pick an area of the sky that has a lot of stars close together and count how many stars you can see in your field of view through the paper tube. Now look at the same area with the binoculars. What do you notice? Count the stars. You should see a lot more stars. Why do you think that is?

Explanation:
Binoculars are basically two telescopes attached to each other. When you look at stars through a telescope you are increasing the energy arriving at your eyes from the stars in the field of view. That's why you can see more stars through the binoculars than you can with your eyes alone. The glass lenses in binoculars and telescopes bend the light energy passing through them and focus a larger amount of energy in a smaller area making the images appear closer to you whether it is a bird in a tree or a star in the sky. Your telescope is small compared to the ones astronomers use. Think about how many stars astronomers can see on a clear night with their telescopes.

Other Online Educational Activities

StarChild: A Learning Center for Young Astronomers
Activities for middle school and above.
http://starchild.gsfc.nasa.gov/docs/StarChild/StarChild.html

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