Jimmy Westlake: The fireballs of fall
October 27, 2010
Don't be surprised if you see a blazing fireball or two streaking across the heavens while you are out trick-or-treating this weekend.
There's no reason for alarm. It's just the annual Taurid meteor showers reaching their peak of activity.
The Taurid meteors are so named because they seem to spring outward from the stars of our constellation of Taurus, the Bull, rising in the east as darkness falls in late October and early November. The source of the Taurid meteors has been traced back to a comet named Encke — pronounced "inky" — after Johann Franz Encke, the astronomer who first calculated its orbit around the sun, in 1819.
Astronomers now suspect that Comet 2P/Encke is just a fragment of a much larger body that crumbled into pieces thousands of years ago. The orbit of Comet Encke, with its trail of dusty debris, passes close to the Earth's orbit in early November. Some of those cometary fragments rain down into Earth's atmosphere, traveling about 17 miles per second. This causes the fragile particles to burn up about 60 miles high as they plow through our protective atmosphere.
Sometime in the distant past, Comet Encke's debris stream passed close to the giant planet Jupiter and was split into two parallel branches, the South Taurids and the North Taurids.
South Taurid meteors peak about Nov. 5 and North Taurid meteors peak about a week later, around Nov. 12. But a few Taurid meteors can be seen anytime between Sept. 25 and Nov. 25.
Although you can see the Taurid meteors in all parts of the sky, their trails will point back toward the little Pleiades, or Seven Sisters, star cluster in Taurus.
This isn't a particularly rich shower of meteors — you'll only see a half dozen or so Taurids per hour. But what it lacks in numbers, it makes up for in bright fireballs.
The November Taurid meteors are some of my favorites to watch because they tend to be big, bright and slow — so slow, in fact, that you might have enough time to alert your fellow sky-watchers to a meteor by yelling "Look!" before the meteor disappears. I often see them out of my car window in early November, dropping toward the horizon when I'm driving home after dark. With the new moon falling Nov. 5 this year, the early November sky will be moonless and perfect for meteor watching.
It's almost like having the Fourth of July in November, with Mother Nature and Comet Encke providing the fireworks.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published all around the world. His "Celestial News" column appears weekly in the Steamboat Today and his "Cosmic Moment" radio spots can be heard on local radio station KFMU. Also, check out Jimmy's astrophotography website at http://www.jwestlake.com.