Astronomy news for the week starting Friday, June 22, 2001.

As busy as the sky was last week, it is quiet this week. The biggest event seems to be the Moon's passing its first quarter on the evening of Wednesday the 27th just about the time the sky darkens in North America. Four days before that, on Saturday the 23rd, during its ascent of the evening sky in the waxing crescent phase, the Moon passes through perigee, when it is closest to the Earth.

Two planets, mythological opposites, now rule opposite portions of the sky. In the morning, Venus, the ancient epitome of love and beauty shines gloriously, its light a creamy white. This by-far- brightest of all planets now rises south of the classical figure of Aries around 3 AM well before twilight begins to brighten the eastern sky. In the evening, Mars has already risen by sunset. By late evening, its brilliant orange-red glow dominates the southeastern sky between the classical zodiacal constellations Sagittarius and Scorpius. The other ancient planets, those known from ancient times, Jupiter, Saturn, and Mercury, are out of sight, though Saturn can be glimpsed in the early dawn.

Venus and Mars are in reality the opposites of their mythological natures. Venus, for all its planetary beauty, is an inhospitable place, the bright reflecting clouds made of sulfuric acid that float in a thick, dense carbon dioxide atmosphere that drives the surface temperature to 470 degrees C (nearly 900 degrees F), about the temperature of a self-cleaning oven. Mars, on the other hand, is for all its cold near-airlessness, a place we could actually visit, and almost certainly will sometime in the future. The temperature can reach the freezing mark, and powerful evidence shows that water once flowed on the planet, though the air (again carbon dioxide) pressure -- about 1 percent that of Earth's -- no longer allows it.

As the sky darkens, orange Arcturus shines high to the south, reddish Antares down and to the left and to the right of Mars. Compare their colors. Which appears the reddest? We probably all differ in our assessments. Down and to the right of Arcturus, Spica shines blue-white, the color contrast between it and the other three bodies quite noticeable. To the right of Spica is the box of stars that makes Corvus the Crow, a springtime constellation now making way for the stars of summer. Farther yet below Spica are the sprawling stars of northern Centaurus. If you are reasonably south of about 40 degrees north latitude, you might glimpse the fuzzy ball of the grandest globular cluster of stars in the Galaxy, magnificent Omega Centauri.
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