Why do stars twinkle?
Because stars are so incredibly distant, to our eyes they appear strictly as points in the night sky. Irregularities in Earth's atmosphere cause starlight to dance around, and the minute changes in the path the starlight takes through the atmosphere results in apparent changes in color -- the familiar "twinkling" effect.
Planets, however, actually form a tiny but definite circle on the sky just large enough to counter the distorting effect of turbulence. Such extended objects only "twinkle" when their light passes through very large amounts of atmosphere, such as when they lie close to the horizon.
» FAQs about StarDate Online
Stars and Nebulae Links
StarDate's Black Hole Encyclopedia
Stars and Constellations
Virtual Trips to Black Holes and Neutron Stars
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