Celestial News: Here come the Perseid meteors
Steamboat Pilot & Today
A shower of meteors is a sight to behold, and the annual Perseid meteor shower is arguably the best meteor shower of the year.
This year, the peak of activity occurs on the night of Aug. 12 and 13 when a single observer might see a meteor a minute.
On the night of peak activity, the nearly full moon will drown out many of the fainter meteors until it sets around 4:20 a.m. That will leave the last dark hour before dawn perfect for watching Perseid meteors. Prior to moonset, just keep the moon at your back and watch for meteors in the sky opposite the moon.
I’ve watched the Perseid meteor shower nearly every August since 1972, and it has never failed to impress. I liken meteor watching to sitting under a shady tree with a fishing pole in the water. The anticipation that the next dip of the bobber might be “the Big One” is enough to keep me sitting there all afternoon.
Here are 10 tidbits of information about meteor showers in general and the Perseid meteor shower in particular.
- Perseid meteors have been observed every August since at least 258 AD. That’s the year that the Romans martyred a Christian deacon named Laurentius on a hot gridiron. As Laurnetius’ family carried away his body, they noticed a number of bright streaks shooting across the sky, and they marveled at the miracle, believing 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 the comet that now bears their names. Four years later, Italian astronomer Giovanni Schiaparelli pointed out that the particles that produce 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 fluffy dust shed by Comet Swift-Tuttle enter the earth’s atmosphere at 130,000 mph and burn up as fiery meteors about 60 miles over our heads.
- These dust particles are so tiny that you easily could hold 1,000 of them in the cupped palm of your hand. When you see the bright streak of a meteor, you are not seeing the tiny speck of dust itself, but the 1-meter wide column of air surrounding it that is heated to incandescence by the speeding particle.
- While in space, the tiny specks that produce meteors like our Perseids are called meteoroids. They graduate to meteors when they enter our atmosphere and create the bright streaks of light that some folks call “shooting stars.” Larger meteoroids that survive their meteoric plunge through the atmosphere and reach the ground become meteorites.
- A meteor shower is named after the constellation from which the meteors appear to spring. The Perseid meteors seem to stream out of our constellation named for Perseus, the Greek hero who killed Medusa.
- You’ll always see more Perseids after midnight than before for the same reason that you see more bugs splatter on your car’s front windshield than on its back windshield. Before midnight, we are peering out of the Earth’s rear windshield, as it speeds through space at 19 miles per second. Any meteors that you see before midnight must be traveling fast enough to catch up with the speeding earth. After midnight, earth’s rotation turns us such that we are facing the direction that it is traveling, so we peer out of the front windshield as it collides with lots of meteoroids.
- Perseus rises in the northeastern sky around 9 p.m. on the night of the peak, just as darkness falls. This allows the opportunity to see some fantastic “Earth-grazing” meteors that streak all the way across the sky, from Perseus in the northeast all the way to the southwestern horizon. Give a look and, with a little luck, you might get rewarded with a rare and beautiful sight.
- John Denver, in his classic song “Rocky Mountain High,” alludes to the Perseid meteor shower with his famous line: “I’ve seen it raining fire in the sky.” The story is that he witnessed the meteor display one August during a family camping trip near Aspen.
- Bright Perseid meteors tend to leave glowing trails that can last for many seconds after the meteor itself has vanished. I witnessed one “shadow caster” in 2004 that left a smoke trail that remined visible for several minutes after the blinding flash. Anticipating another “Big One” like that is what keeps me awake until dawn on the night of the Perseid peak.
If you miss the morning of peak activity, don’t worry. Perseid meteors in fewer numbers can be seen for several nights before and after the peak.
Happy meteor watching.
Jimmy Westlake retired from full-time teaching at Colorado Mountain College’s Steamboat campus in 2017, after 19 years as their professor of physical sciences. His “Celestial News” column appears monthly in the Steamboat Today newspaper. Check out Jimmy’s astrophotography website at jwestlake.com.
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