One night only: Leonid meteor shower

The annual Leonid meteor shower will make its one-night appearance over North America tonight. Viewing conditions should be excellent because the peak will occur after midnight, when the lights of metropolitan areas will be at their dimmest.

Further, the presence of a new moon will make it much easier to see the white streaks across the sky.

The meteor shower is called the Leonids because the meteors appear to originate in the constellation Leo. In reality, they appear only in the last few seconds of their existence when they enter the upper atmosphere of the Earth.

Most of the meteors are small bits of sand and fluff shed by the 55P/Tempel-Tuttle comet, which makes a close pass of the sun every 33 years before returning to the outer solar system. The last close pass of the comet, which is about 2 miles in diameter, was in 1998.

Each time it traverses the inner solar system, the heat of the sun causes the comet to lay down a trail of debris. When the Earth’s orbit carries it through this trail, that becomes the Leonid shower.

For more information on meteor showers, check out StarDate Online or NASA’s website.