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 altitudes of about 100km (60mi). The 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 70km s-1 (7 to 45mi s-1).
A few meteors per hour may be seen on any clear, moonless night at any
time of the year. But at certain times of the year there are meteor
showers, which occur when the Earth passes through dust particles
spread around the orbit of a comet. Most of the meteors appearing during
the year are sporadic meteors, not associated with cometary orbits.
- A meteor is also the particle itself during entry. Very large, bright meteors are known
as fireballs or 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.