Several times a year, as the earth travels on its path around the sun, it passes through the orbit of a disintegrated comet and the stream of particles that once made up the comet. These particles, most of them extremely small (like a grain of sand or a small pebble), appear as "shooting stars" as they come into the earth's atmosphere and burn up from the heat caused by friction with our air. These periods are called meteor showers. During a meteor shower "shooting stars" can be seen as often as approximately once a minute if seen at the right times from a dark place. Occasionally a sporadic meteor is larger and extremely bright, leaving a visible burning path as it crosses the sky. This is called a "fireball". Some even make it all the way to the ground as meteorites.An interesting phenomenon associated with meteor showers, or with "shooting stars" in general, is that there are more of them and they are brighter after midnight (or after 1:00 a.m. during daylight savings time). To understand why, think of a car traveling fast on a hot summer's evening. As the car travels, it collides with bugs that smash against the front windshield. They rarely hit against the rear windshield even though just as many fly by there. This is because the front windshield faces the direction of the car's travel.
The Earth has two motions. One is its year long orbital movement around the sun. The other is its daily spinning around it own center. As the earth spins around its center once each day, it is after midnight that the part of the earth we are on spins around to a position in which we face the direction of the earth's travel around the sun. After midnight, we are colliding head-on with any meteors in the Earth's path. Prior to midnight we only collide with those meteors that are fast enough to catch up to the moving Earth from behind. Even those that are able to do that aren't moving as fast relative to the Earth, and therefore don't glow as brightly as they burn up in the Earth's atmoshere.
For the same reason that most bugs hit the front windshield of a moving car, it's best to watch for meteor showers or shooting stars after midnight.
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