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Comets
Comets orbit the sun in regular cycles. Draw a sketch of a comet's structure.
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Telescopes Science
& Technology Education Center, Tel-Aviv University
Using a refracting telescope, the ancient astronomer Galileo discovered that Venus went through phases, like Earth's moon. This evidence supported the idea that the sun is the center
of the solar system. Go to this site to construct a working telescope for night-sky gazing.
