Sky Watch

by J. Alex Knoll

Halley’s Legacy

Cosmic debris ignites in our skies

The mighty hunter Orion stands high in the southwest as he greets the dawn. While you should easily recognize the trapezoid-shaped figure with his raised club and belt of three stars, don’t be surprised if you see stars shooting from this celestial giant.

Each year this time, Earth passes through the trail left by Halley’s Comet. As these tiny bits of cosmic dust and ice smash into the atmosphere, they ignite and streak through our sky. For thousands of years, people have marveled and trembled at the sight of the Orionid meteor shower.

We’re at the tail end of the week-long Orionids, but even so, you’re likely to spot more than a few streaking through pre-dawn skies. The meteors appear to emanate from the constellation Orion, which rises in the east after 10pm. But the most activity comes between midnight and dawn, when Orion stands high overhead. Typically following a 12-year cycle, this year’s Orionids are expected to deliver as many as 30 meteors an hour.

Halley’s comet has been trapped in orbit around our sun for thousands of years, every 76 years venturing into the inner solar system. The last such visit was the winter of 1985-’86. During these forays within the sun’s warmth, the comet’s outer surface melts a bit, dumping a fresh load of dirt, dust and ice in this band of cosmic flotsam circling Earth.

In the night sky, Jupiter is unmistakable high in the south at sunset, around 6:15 this week. Look for it just a few degrees below the waxing gibbous moon from sundown Monday until the two set in the west around 1am.

Mars rises in the northeast at midnight. Saturn rises in the east at 5am, and an hour later Venus appears before the rising sun.

Illustration: © Copyright 1925 M.C. Escher/Cordon Art-Baarn-Holland; Graphics: © Copyright 2009 Pacific Publishers. Reprinted by permission from the Tidelog graphic almanac. Bound copies of the annual Tidelog for Chesapeake Bay are $14.95 ppd. from Pacific Publishers, Box 480, Bolinas, CA 94924. Phone 415-868-2909. Weather affects tides. This information is believed to be reliable but no guarantee of accuracy is made by Bay Weekly or Pacific Publishers. The actual layout of Tidelog differs from that used in Bay Weekly. Tidelog graphics are repositioned to reflect Bay Weekly’s distribution cycle.Tides are based on National Oceanic and Atmospheric Administration and are positioned to coincide with high and low tides of Tidelog.

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