The Leonids Meteor Shower

Boasting some of the fastest meteors of any shower, the Leonids this week may be easy to find too difficult to actually spot, both because of the moon.

"The quarter-phase moon" when the lunar disk appears half dark "will interfere with meteor watching this year," comments Ben Burress, staff astronomer at the Chabot Space and Science Center in Oakland, California.

"But since [the moon] won't rise until after local midnight, and meteors can be seen in the earlier hours as well, there is a spell of time in the evening of the 17th when the sky will be moonless and darker, making for good conditions for viewing," Burress said.

Small Meteors

For example, stargazers worldwide can try to gaze at the eastern sky during predawn hours on Friday, when the Leonids’ peak will show around 20 visible shooting stars an hour.

Astronomers are also predicting that as many as three outbursts will occur where there will be as many as 200 meteors an hour. But, since the particles in the shower will be extremely small – just around a hundred thousandths of a millimeter across – these outbursts will most likely go unseen by observers, even in extremely dark places. All Leonid meteors seem to radiate from their namesake constellation, Leo, and stargazers will have a few destination options as to where to watch the event.

"At midnight the meteors, radiating from Leo, will be coming from the east point on the horizon, and since the moon and Mars are both inside the constellation Leo this year, they are perfect visual markers for the shower's radiant point," Burress commented.

Tempel-Tuttle

Like its more well-known relative, the August Perseids, the Leonid meteor shower happens when Earth goes through a trail of debris left in the remains of a comet orbiting the sun – in this instance, the 1.2-mile-wide comet Tempel-Tuttle.

Every 33 years, as this comet approaches the sun, melting ice releases particles of dust – many of them no larger than a grain of sand – and plants them in clumps along the comet’s orbit.

Every year, Earth crosses path with these particle clouds, many of which catch fire in our atmosphere and produce elusive shooting stars or meteors. Sometimes a larger object – actually the size of a pebble or boulder – will create a beautiful, slower fireball that leaves smoke trails as it passes; these trails can sometimes last for up to a minute.

Since the Leonids are heading towards the Earth as the planet runs into them, these meteors tend to be the speediest ever recorded, with speeds of up to 130,000 miles (210,000 kilometers) per hour. People have had knowledge of the Leonids for centuries, but the most famous incidents involving the meteors was the major Leonid outburst of 1833. Stargazers saw a storm of thousands of meteors per hour – an event that changed the way people view meteor showers.

"It was [the] observation and study of the 1833 outburst that led to the understanding that meteors are a phenomenon coming from space, not originating, as previously speculated, solely from Earth's atmosphere," Burress said.

National Geographic Photo by : Phillip Chee