A meteor is the light phenomenon, known popularly as a shooting star or falling star, that results from the entry into Earth's atmosphere of a solid particle, or meteoroid, from space. Meteors occur at an altitude of about 100 km (60 mi). A typical meteor lasts for a few tenths of a second to a second or two, depending on the meteoroid's entry speed, which can vary from about 11 to 70 km/s (7 to 45 mi/sec).
A sporadic meteor is a meteor that occurs randomly, instead of being associated with a meteor shower. Sporadic meteors can be seen on any clear night, with rates varying between 3–4 meteors per hour in the northern spring to 8–10 meteors per hour in the autumn. As well as this seasonal variation, there is also a nightly variation – hourly rates being generally higher just before dawn than they are in the late evening. At certain times of the year meteor showers occur, when Earth passes through dust particles spread around the orbit of a comet.
Very large, bright meteors are known as fireballs or (if they causes a sonic boom) bolides.
A meteor train is a trail of ionized dust and gas that remains along the path of a meteor. A persistent train is one that remains visible for more than a second.