The Geminid meteor shower will peak tonight.

One of the year's most powerful meteor showers, the Geminids, is predicted to peak on the night of December 13-14. Like most meteor showers, the Geminids consist of material (primarily small dust particles and pebbles) lost by a larger body as it orbited the Sun and dispersed along its orbit. The parent body of the Geminids is the asteroid Phaethon, approximately 5 km in size, which orbits the Sun every 1.5 years and intersects the orbits of four planets—Mercury, Venus, Earth, and Mars.

Meteor showers are typically associated with comets, not asteroids. This easily explains the source of the abundant material dispersed along the comet's orbit—it simply flows out of the comet's tail. Since this model doesn't work in the case of Phaethon, it is hypothesized that the asteroid is the nucleus of an ancient comet that has completely exhausted its supply of volatile material. Another hypothesis is that the asteroid passes very close to the Sun each time it orbits the Sun—approximately 20 million km. Perhaps the sun's heat is causing its rocks to crack and fragment, and these fragments have formed a dust cloud along its orbit over many years, the densest part of which Earth will cross tonight.

The meteor shower will be visible from approximately 10:00 PM to 2:00 AM. Soon after, the Moon will rise, making viewing conditions somewhat less favorable. At 10:00 PM local time, the center (radiant) of the meteor shower will be in the east, near the planet Jupiter, which is now clearly visible in the sky (map attached). The easily identifiable constellations of Ursa Major and Orion are also good landmarks. The radiant is located between them. Later, the center of the meteor shower will shift toward the southeast and south, but its position relative to the constellations will remain the same.

The average expected rate of "starfall" in clear skies can range from 10 to 100 meteors per hour. If you're lucky, you might also see brighter and larger fireballs.