The origin of meteors has its own shelf in the astronimcal library.   Astronomers believe that an estimated 1,000 tons of meteoric dust and rock enter the Earths atmosphere every day from deep space.  The dust and rock could have come from supernovas(exploding star), collision of meteors, chips off asteroids, and just pieces still floating around from formations of planets and moons.  Another way that meteors form are from comets.  When comets get closer to the sun, the suns heat waves melt the comets ice that was holding the meteoric dust and rock, letting the debris fall.   Some astronomers believe that some comets have held their debris for nearly five million years.