One of the best meteor showers of the year is on tap for mid-November. The Leonid meteors, a regular shower that occurs every year at the same time, are caused by the dust trail of Comet Tempel-Tuttle when it passed Earth's vicinity in 1932. The tiny fragments of the comet that were left in its wake as it sped through the solar system lie in wait for Earth. As Earth makes its yearly progression around the sun, it hits this old comet trail every November and the small bits of dust and rock strike our atmosphere, causing them to be heated and glow, looking like stars streaking across the sky and burning out all in a fraction of a second.
Start looking on the evening of Friday, November 17, and keep checking for meteors until sunrise on Monday morning, the 20th. Fortunately, a new moon occurs on the 20th, which will help to make these faint meteors easier to see. The very best time to watch appears to be about a quarter to midnight Eastern Time on Saturday night, the 18th. Starting then and lasting for about three hours, Earth is expected to pass through a dense part of the debris stream, which could yield up to 100 meteors per hour.
Viewers in North America are at a disadvantage because the radiant, lying in the constellation Leo (thus the name Leonids), is just starting to rise above the Eastern horizon. Except for the predicted outburst around midnight November 18 and the early morning hours of November 19, the best time to view the Leonids is in the morning hours when the radiant is well above the horizon, which allows a better chance to see the meteors streaking in all directions.
Leonid meteors are some of the fastest meteors around. If you are watching with a partner, you will have not much more time to gasp and begin to point before the meteor has disappeared. Occasionally larger meteors will leave smoky-looking trains that marked where they sped just seconds before. Especially bright meteors, caused by larger pebbles or even very small rock-sized debris, are called fireballs or bolides.
The terms meteor, meteoroid, and meteorite are often confused. Meteoroid is the rocky body that is in interplanetary space and has not yet made contact with Earth's atmosphere. Once the rocky body hits Earth's atmosphere and burns brightly it is called a meteor. If the rocky body is large enough to survive its super-heated passage through Earth's atmosphere all the way to the surface of our planet, it is then called a meteorite.
