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Stars set to fall on Alabama Sunday
Sunday night should be quite a sight

By Paul Huggins
phuggins@decaturdaily.com ∑ 340-2395

Perseus didn't need the cloak of darkness to slay the snake-haired Medusa, but dark skies this weekend will help him deliver a memorable meteor shower.

The Perseid meteor shower makes its annual August visit, and this year promises to be more spectacular than usual.

The celestial event coincides with a new moon Sunday night. The extra darkness will let more meteorites shine as they smash into Earth's atmosphere like bugs on a windshield, albeit bugs traveling at 130,000 mph. That's 37 miles per second.

1-2 per minute

How good will the show be?

Normally, with some moonlight during a Perseid show, skygazers can see one meteor streak across the sky every five minutes.

This year, you'll be able to see one or two meteors per minute, said Bill Cooke, head of the Meteoroid Environment Office at the Marshall Space Flight Center.

"The moon washes out the faint meteors, so with no moonlight this year, you'll see bright ones, faint ones, practically everything."

Although often mistaken for shooting stars, the Perseid meteors are actually fragments of the ancient Swift-Tuttle comet that passes through the inner solar system every 130 years.

It's not the size of the meteor but its speed as it strikes the atmosphere that generates the fiery streak.

Most range in size from smaller than a grain of sand to the size of birdshot, said Loren Ball, an amateur astronomer who has discovered 147 asteroids from his home observatory in Southeast Decatur.

"And if you see something that makes you go, 'Oh wow! I can't believe it,' and everyone's talking about it at the water cooler the next day, it's probably the size of a golf ball.

"And if you ever see anything as big as a Buick, you'll think the world is coming to an end," Ball said.

He said a basketball-sized meteor is bright enough to cast shadows and fool streetlights into thinking it's daytime and turn off.

Cooke and Ball said the best thing about a meteor shower is you don't need a telescope or binoculars. All people need is a reclining lounge chair, inflatable mattress or blanket and pillow.

"It's probably the cheapest way to watch the night sky," said Cooke, whose job is making sure NASA spacecraft don't get bombarded with meteors. "Lay back, play your iTunes and watch the meteor show overhead."

The shower will become most active at about 2 a.m. Cooke said, but meteors will start appearing over the horizon just after dark and continue until first light.

At about 9 p.m., sharp-eyed observers might get lucky enough to see "earthgrazing" meteors that skim the northeast horizon.

Earthgrazers are long, slow and colorful, he said, and extremely rare.

"I've seen one in my lifetime," he said.

Though Perseid meteors often streak across the entire sky, skywatchers should focus on the northeast sky for the most active starting points. The constellation Perseus dominates this portion of sky, which is why astronomers dubbed the meteor shower Perseid.

If you can't stay up late Sunday night into Monday morning, Cooke said, Saturday and Monday nights will offer decent shows, with one meteor appearing every five minutes.

If you have binoculars or a telescope and want something to watch while the meteor show warms up, Ball recommends Jupiter.

Skywatchers simply need to face due south and look a little above the horizon. Jupiter will be the brightest object in the sky, nestled just behind the head of the Scorpius constellation and a little more to the left of Libra.

"Just with binoculars, you can see the moons of Jupiter," Ball said.

Meteor notes

Meteoroids are any type of small, solid materials traveling in outer space. When they enter Earthís atmosphere, they become meteors. Almost none hit the ground, but if one does, itís called a meteorite.

Comet Swift-Tuttle, whose debris creates the Perseid shower, is the largest object known to make repeated passes near Earth. Its nucleus is about six miles across, roughly equal to the object that some scientists believe wiped out the dinosaurs.

When a Perseid particle enters the atmosphere, it compresses the air in front of it, which heats up, possibly to more than 3,000 degrees Fahrenheit. The intense heat vaporizes most meteors, creating what we call shooting stars.

Youíre likely to see twice as many meteors per hour in the predawn hours as compared to the evening hours. As the Earth rotates, the side facing the direction of its orbit around the sun tends to scoop up more space debris. This part of the sky is directly overhead at dawn.

Comet Swift-Tuttle was last seen in 1992, an unspectacular pass through the inner solar system that required binoculars to enjoy.

SPACE.com

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