Got a calendar? Circle this date: Friday, August 12. Next to the circle write "before sunrise" and "Meteors!" Attach all of the above to your refrigerator in plain view so you won't miss the 2005 Perseid meteor shower.
The Perseids come every year, beginning in late July and stretching into August. Sky watchers outdoors at the right time can see colorful fireballs, occasional outbursts and, almost always, long hours of gracefully streaking meteors. Among the many nights of the shower, there is always one night that is best. This year: August 12.
Right: A colorful Perseid streaks over Half Dome in Yosemite National Park. Photo credit: Dirk Obudzinski, August 12, 2004. [Gallery]
The source of the shower is Comet Swift-Tuttle. Although the comet is nowhere near Earth, the comet's wide tail does intersect Earth's orbit. We glide through it every year in July and August. Tiny bits of comet dust hit Earth's atmosphere traveling 132,000 mph. At that speed, even a tiny smidgen of dust makes a vivid streak of light--a meteor--when it disintegrates. The shower is most intense when Earth is in the dustiest part of the tail.
Perseid meteors fly out of the constellation Perseus, hence their name. The best time to watch is during the hours before sunrise when Perseus is high in the sky: sky map. Between 2 a.m. and dawn on August 12, if you get away from city lights, you could see hundreds of meteors. Scouts, this is a good time to go camping!
Above: A Perseid sky map. The red dot denotes the shower's radiant, a point in the eastern sky from which meteors appear to stream. [Larger sky map].
Really, it could hardly be better. The Perseids come on a warm summer night. (Note: This is a northern hemisphere shower.) Other familiar meteor showers like the Leonids of November require a parka to enjoy. All you need for Perseids are light pajamas.
And there's a bonus: Mars.
In the constellation Aries, right beside Perseus, Mars is shining like a bright red star. Step outside before sunrise, look east, and you'll find you have a hard time taking your eyes off Mars. There's something bewitching about it, maybe the red color or perhaps the fact that it doesn't twinkle like a true star. It's steady. You stare at Mars and it stares right back.
Earth and Mars are converging for a close encounter on October 30. Consider August 12 a preview. Mars already outshines every star in the night sky, and it's getting brighter every night. If you like August, you'll love October.
And you will like August. Picture this: It's four in the morning. The sky is dark. The breeze is pleasant. Mars is beaming down from the east while meteors flit across the sky.
Maybe you should go circle the calendar again.
Editor's Notes: (1) The Perseids are a northern hemisphere meteor shower. Southerners can see Perseids, too, but at greatly reduced rates. (2) All times mentioned in this story are local, so, e.g., "2 a.m." means 2 o'clock in the morning in your time zone.SpaceWeather.com -- visit this site in August for up-to-date reports and pictures of Perseid activity
2004 Perseid Meteor Gallery -- (SpaceWeather.com)
Beware the Mars Hoax -- (Science@NASA) There's a rumor going around about Earth and Mars....
The Perseid Meteor Shower Visits Earth -- (Jack Stargazer)
Periodic Comet Swift-Tuttle -- (APOD) Comet Swift-Tuttle is the largest object known to make repeated passes near the Earth.
3D Orbit -- (JPL) view the orbit of comet Swift-Tuttle from any angle, and find out where the comet is now.