When astronomers predicted that two comets would be visible to the naked eye from Earth this year, headlines like "The Year of the Comet" appeared. The first comet, PANSTARRS, may be seen in our locale as soon as Thursday.

The iconic image of a round-headed celestial object with a long, diaphanous fantail is alive in our imaginations. The first definitive record comes from a Chinese historian who noted observing a "broom star" in 240 B.C. The February issue of Astronomy magazine shows the presence of a comet in both a textile from 1066 A.D. and a 14th century Giotto painting.

In 2013, we see comets on linens and toys in a child's bedroom; brilliant stars with tails have been adopted to lend their power and light to a scouring powder, a now-vintage car, a newspaper.

The real thing will pass closest to Earth on Tuesday, according to NASA. It will be 100 million miles distant in its trajectory toward the sun. (Earth averages 94 million miles from the sun.)

PANSTARRS should gain brightness at its closest approach to the sun. On March 10 the speeding, "dirty snowball," or "icy dirtball," will dip inside the orbit of Mercury, second planet from the sun, and by March 12 it emerges from the sun's glare and could be visible to the naked eye close to the western horizon shortly after sunset, below the crescent moon.

Astronomers refer to this comet as C/2011 L4 (PANSTARRS) because it was first spotted in 2011 with the Panoramic Survey Telescope and Rapid Response System telescope in Hawaii.


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Next week, read more about PANSTARRS and enjoy an introduction to November's Comet ISON, which could become as bright as the full moon.

Contact Judy Isacoff at www.naturesturn.org.