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Meteor or ‘shooting star’ is a bright streak (meteor trail) across the night sky resulting from the heat generated when a particle or piece of matter traveling at a high velocity in space enters the Earth’s atmosphere. The particle itself is called a meteor, but it is preferable to designate it as a meteoroid. A meteoroid then produces a meteor when it encounters and interacts with Earth’s atmosphere. A very bright meteor is called a fireball, and a large fireball (particularly one accompanied by sparks and explosive noise) is called a bolide. While most meteoroids will disintegrate into small particles and dust upon entering our atmosphere, some of the very largest will make impact with the surface of the Earth creating large craters. A list of some of the most famous meteor craters follows this article.

There are two main types of meteors: sporadic and recurrent meteors (showers). Sporadic meteors may be seen on almost any night of the year at a rate of 5 to 7 per hour and show no preferred direction in the sky. The greatest frequency of sporadic meteors occurs after, rather than before, midnight. Between midnight and dawn an observer is facing the same direction as the Earth is moving in its orbit and he can see all of the meteors formed by the meteoroids traveling toward him (from the left), no matter what their velocity). On the other hand, between dusk and midnight, the only meteors that are visible are those produced by meteoroids coming toward him (from the right) with sufficient velocity to overtake the Earth.

The other type of meteor that occurs is the meteor shower. Meteor showers occur at relatively fixed times of year and seem to originate from a fixed point in the heavens known as a radiant. Meteor showers take their names from the constellation or star near where their radiant position is located and most occur each year with great regularity. The display of the Leonid shower on November 12, 1833 was so striking that meteors were described as ‘falling like snowflakes from the sky’ and no section of the heavens was not filled with thousands of meteors. These permanent showers occur as the Earth sweeps through the concentrations of dust and debris in space. This debris is moving in orbit about the Sun. After A few days, the Earth moves through and beyond the particular debris. Orbits of a general sort are known for the principal showers and some of the major showers are presented in the diagram above. Most meteor shows occur regularly each year, some every few years and in several cases a shower has been completely lost or has vanished.

Radio-echo technique has greatly expanded our understanding of meteor showers by allowing us to very accurately record these events. In at least three major cases, this technique has discovered new radiant points occurring only through the daylight hours (daytime showers).