Time for the annual Perseid meteor shower

  • Thu Aug 2nd, 2012 3:19pm
  • Life

By Mike Lynch

The annual Perseid meteor shower is one of the celestial old faithfuls, showing up every August in the Northwest skies.

It’s one of the two best annual meteor showers that we have, and this year moonlight won’t get in the way like it did last year when a full moon washed out many of the meteors.

When the Perseids peak next Saturday night and Sunday morning, Aug. 11 and 12, the skies will definitely be dark as we’ll only have a thin crescent moon rising in the eastern sky after 1 a.m.

There’s some debate here, but the Perseids are thought by many amateur and professional astronomers to be the second best meteor shower of the year.

The Geminid meteor shower in December is said to put on a slightly better show with more meteors or “shooting stars” per hour, but watching the Perseids is a lot more comfortable, and this year the peak of the shower is on a Saturday night.

Even though the meteor shower peaks next weekend you can actually see some Perseids early mornings this week.

After midnight, especially from 2 a.m. to 5 a.m., is the best time to view the Perseids. If the clouds get in the way on the weekend, you may even see quite a few early on Aug. 13.

The views will be better in the darker countryside. A Perseid campout is a great idea. Away from city light pollution, you may see 50 to 100 meteors an hour.

The meteors are called shooting stars and look like stars, but are actually just grains of dust and pebbles. The biggest ones may approach the size of small walnuts. This is all debris left behind by comets that have passed by Earth and the sun.

Comets are basically dirty snow or ice balls that partially melt when they get close to the sun. Debris from these partially melted comets is left in their wake, and gravity between the particles keeps the debris trail intact.

The debris trail that causes the Perseids is from comet Swift-Tuttle, which visits this part of our solar system about every 130 years and last came by in 1992.

There is some thought that Swift-Tuttle could possibly collide with the Earth in 2126, but that’s been played down by a lot of astronomers.

In the meantime, tiny pieces of comet Swift-Tuttle will slam into our atmosphere at speeds of more than 40 miles a second, easily incinerating them before they can get anywhere near us.

Most of the light you see from meteors as they streak across the sky is not caused by their flaming death, but by ionization. These debris particles are zipping through our atmosphere so fast that the column of air they are going through is being destabilized.

Meteors come in different colors, depending on what kind of atmospheric gases they go through. Many of them change colors as they rip across the sky.

They are called the Perseids because all of the meteors seem to emanate from the general direction of the constellation Perseus the Hero.

The best way to watch a meteor shower is recline on a lawn chair or the ground and roll your eyes all around the sky. It’s possible you could see two meteors every minute in the early hours next Sunday.

As an added bonus early Aug. 12 you’ll see two bright stars on either side of the moon. To the lower left of the moon is Venus, about 65 million miles from Earth right now. To the upper right of the moon is Jupiter, just under 500 million miles away.

Mike Lynch: www.lynchandthestars.com.