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Showtime in the skies offers meteor shows, lunar eclipse

August 9, 2007 12:35 am

AUGUST'S DOG days will have no bite compared to what awaits us after dark this month as two major events grace the Fredericksburg area's skies.

Meteors associated with a meteor shower will streak across the sky midmonth, and a total lunar eclipse will be visible at the end of the month. Both events are perfectly safe to watch and do not require binoculars or telescopes.

Let's first talk about meteor showers. As a comet travels through space and approaches the sun, it sheds particles. When the pieces of comet fragments enter the Earth's atmosphere, they burn and glow due to friction, creating the momentary streaks of light we see as meteors.

Particles in a meteor shower are generally very small, usually no bigger than a grain of sand, so don't worry about them making it to the ground. Meteors that are large enough to reach the ground are called meteorites. They are fairly rare, but they do occur.

People may commonly refer to meteor showers as "shooting stars" or "falling stars." But the momentary streaks of light we sometimes see are not associated with stars at all.

Several meteor showers occur regularly each year, but the Perseid meteor shower in August is among the best. It is so named because the meteors seem to radiate from the constellation (a group of stars) named Perseus.

This year's shower during the night of Aug. 12 through the early morning of Aug. 13 will be especially visible since the moon won't be in the sky to spoil the show.

Don't worry if you can't identify the constellation Perseus in the night sky. Just look in the northeastern sky between midnight and dawn for the best part of the cosmic fireworks show.

Try to get as far away from the city lights as possible. Grab a lawn chair, insect repellent, and a blanket to keep you comfortable. As your eyes become adapted to the dark, you will see meteors radiating from a point in the northeastern sky, an effect similar to driving in a snowstorm at night with your headlights on.

If you're lucky, you will see at least one meteor per minute, but meteor showers sometimes exceed predictions.

The second major event this month is a total lunar eclipse. Unlike a solar eclipse, a lunar eclipse is safe to watch. As the diagram shows, a total lunar eclipse occurs when the full moon fully enters the Earth's shadow in space. Although it's not depicted in the diagram, the Earth's shadow is actually comprised of two parts: a dark inner area and a pale outer portion, just like your own shadow on a sunny day.

Lunar eclipses do not occur every month because the moon's orbit is usually not perfectly aligned with the Earth's shadow during the time of a full moon. When a total lunar eclipse does occur, the full moon becomes slowly engulfed by the Earth's shadow.

During the deepest part of the eclipse, the moon can take on shades of gray, orange, yellow, and red, or it may become nearly invisible. The colors are caused by a small amount of sunlight being filtered by the Earth's atmosphere and reaching the moon.

On the morning of Aug. 28, the moon will begin to enter the Earth's shadow before 5 a.m.; the total eclipse will begin before 6 a.m.

The deepest part of the eclipse will occur before 6 a.m., just as the moon is setting in the west. Make sure you have a clear western horizon free of trees and buildings to watch as much of the event as possible before the moon sets.

Mark your calendars for the meteor shower and lunar eclipse early on the mornings of Aug. 13 and 28 respectively. If you're not an early riser for these events, you can view a prime-time pairing of the moon and Jupiter during the entire evening of Aug. 21. Jupiter will be the bright starlike object above the moon.

The Rappahannock Astronomy Club hosts monthly star parties where you can view the moon, planets, and other celestial objects through amateur telescopes. For more information, go to raclub.org.

The Phoenix Mars Mission lifted off Saturday on a journey to the planet Mars.

Once it lands on Mars in the late spring of 2008, Phoenix will research the history of water on the planet's northern polar region and will try to resolve if the Martian soil could sustain life.

The spacecraft comes equipped with many high-tech instruments including a robotic arm to scoop up the Martian soil, a robotic arm camera, an on-board wet chemistry lab, and an advanced weather station. Learn more about this exciting mission at phoenix.lpl.arizona.edu/ and get ready for some out-of-this-world excitement in 2008.