Meteors are the transitional stages between meteoroids and meteorites. An object is only considered a meteor as it is falling through the air. Alternatively, the term "meteor" may apply only to the visual phenomenon of such a rock heating up and glowing, streaking across the sky.
While meteors can be seen on any dark, cloudless night, they sometimes come in bursts known as meteor showers. Such events, lasting from hours to days, occur as Earth's orbit takes it through a particularly dense cloud of debris, which is often shed from a comet. Meteors associated with a given debris collection will appear to originate from the same point in the sky (the radiant), and the name of the corresponding annual meteor shower is often derived from the constellation in which this point is located.