Lion’s share of meteors

November 23, 2009 at 01:25 PM

The Lion is about to roar. It’s not the Lion Aslan in the C.S. Lewis classic “The Lion the Witch and the Wardrobe.” This time it’s the famed Leonid Meteor Shower, which on rare occasions bursts forth in glory.

They radiate from a point in the constellation Leo the Lion.

Meteor showers reoccur annually on the same general date, when Earth crosses the path of the meteors’ orbital stream. The meteoric particles, which originate from disintegrating comets and sometimes asteroids, spread out around the usually long elliptical path. The Leonids have a heavy concentration in a section of its path. Every so often the Earth will meet up with this bombardment and we have a heavenly display largely unparalleled.

The last huge outburst occurred in November 2001. Astronomers are predicting there may be an outbursts around the time of Nov. 17 and 18, with as many as 100 meteors an hour.

Prospects to see them in large numbers are extra enhanced because the moon happens to be at new phase on the 17th. That means the sky will be dark. You will see the most meteors if you look well after midnight, on the morning of the 18th. The shower’s radiant, in Leo, is not well above the eastern horizon until around 2 a.m.

On most years, you might see only 20 to 30 Leonid meteors in an hour, under good conditions.

On very rare occasions, the Leonid shower was better described as a meteor storm, cascading down at rates of thousands of meteors an hour. These events were chronicled as epochal, for many harbingers of the end of the world.

You could see meteors during the evening, but they are scarce because we are on trailing side of the planet. As the Earth turns, we rotate around with it. Once we pass the midnight point, we are on the leading side of the world, the side of the planet facing where the Earth is aimed in its travel around the Sun. This is the “front end” side, where we get “front end collisions,” as we plow through meteor streams. Thus, we get more meteors darting across the sky after midnight.

A good, clear open sky away from city lights is also needed to see the most meteors. The bright ones, however, will still startle even the city dweller.

Meteors are always a nice surprise. Last week I was peering through my telescope looking for a galaxy, and a meteor crossed the eyepiece’s field of view! It appeared as a bright ball, moving very fast and leaving behind it a thin gray streak, which vanished in about a second.

Keep looking up!