dipper@utastro.UUCP (Debbie Byrd) (06/21/85)
Happy summer solstice! We'll tell you what's so special about this day -- when we come back. June 21 The Summer Solstice Today is the summer solstice -- marking the first official day of summer and the longest day of the year for those in the northern hemisphere. Earth moves around the sun -- and the seasons change -- not primarily because of our distance from the sun -- but mainly because Earth tilts on its axis by 23-and-a-half degrees. During our yearly journey around the sun, the northern and southern hemispheres trade places in receiving the sun's rays most directly. Today, at the summer solstice, the sun is at its northernmost point on the celestial sphere. The sun rises and sets farther north today than on any other day. From anywhere on the Tropic of Cancer, 23-and-a-half degrees north of the equator, the sun is directly overhead at noon. According to astrology, the sun at the solstice is supposed to be seen in the star-sign of Cancer -- that's how the Tropic of Cancer got its name. But in the real sky, if we could somehow blot out the sun today, we'd see it against the background of stars in Gemini, the constellation next door to Cancer. Astrology and real astronomy seldom agree on the locations of celestial objects as seen projected against the stars. That's because of a movement of the Earth called precession -- which has changed our vantagepoint on the stars since astrology was devised thousands of years ago. In 1990, precession will have changed our vantagepoint so much that the sun at the solstice will be lingering in Taurus -- two constellations ahead of where astrology says it should be! Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin