Jimmy Westlake: A great year for Perseid meteors
August 6, 2013
Steamboat Springs — The annual Perseid meteor shower is underway and is expected to peak midday Monday. That means the predawn hours of Monday and Tuesday should provide lots of beautiful shooting stars for skywatchers in Colorado. The 5-day-old moon will set at about 10:30 p.m. Sunday and 11 p.m. Monday, leaving the sky dark for meteor watching.
The Perseid meteor shower is the Old Faithful of meteor showers because, under good sky conditions, it dependably produces 60 to 100 falling stars per hour at its peak. You can expect about one-fourth that number each morning for a week on either side of the peak as the shower rises and falls from maximum activity.
Sometimes referred to as St. Lawrence's Tears, Perseid meteors have been observed every August since at least 258 AD. That's when the Romans martyred a Christian deacon named Laurentius on a hot gridiron. As Laurentius' family carried away his body, they noticed a number of bright streaks shooting across the sky, and they marveled at the miracle, thinking that the streaks were the fiery tears of Laurentius falling from heaven. Centuries later, people the world over continue to marvel every August at the sight of St. Lawrence's Tears.
In 1862, American astronomers Lewis Swift and Horace Tuttle co-discovered a comet that now bears their names. Italian astronomer Giovanni Schiaparelli pointed out that the particles that cause our Perseid meteors orbit the sun in the same path as Comet Swift-Tuttle. That was the first indication that comets could be the source of our annual meteor showers.
We now know that the Perseid meteors are produced when tiny bits of dust shed by Comet Swift-Tuttle enter the Earth's atmosphere at 130,000 miles per hour and burn up as fiery meteors about 60 miles high. These dust particles are so tiny that you easily could hold 1,000 of them in the palm of your hand.
Perseid meteors can be seen in all parts of the sky, but their trails all will point back toward the constellation of Perseus in the northeastern sky. You always will see the most meteors between midnight and dawn because that's when the spinning Earth has you facing the direction from which the meteors are streaming.
Perseid meteor watching is a great family activity. Take the kids and find a nice, dark campground, roll out the sleeping bags and watch nature's fireworks.
Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His Celestial News column appears weekly in the Steamboat Today. Check out Westlake’s astrophotography website at http://www.jwestlake.com.