Several times during the course of a year, the Earth passes through the debris trail left by a comet orbiting the Sun. This ejecta is in the form of tiny bits of dust, usually not much bigger than a grain of sand. Due to its relative speed, though, this stuff plunges into our atmosphere at dozens of kilometers of second, gets very hot, and glows as it zips across the sky in a second or so.
Thus, meteor showers.
A really good shower, like the Perseids or Geminids, might produce up to 50 or 60 "shooting stars" per hour. Sometimes, though we pass through a particularly dense cloud of material, and the number of meteors can increase hugely. These are meteor storms, and can produce over 1,000 meteors per hour.
On the evening of 21/22 November, we may get such a storm.
The normally quiet Alpha Monocerotid meteor shower usually produces a few meteors per hour. However, in 1925, 1935, 1985, and 1995 there were sudden outbursts of meteors from the shower. 1985 produced about 700 meteors per hour (more than 10 per minute!) and 1995 about 400.
Astronomers have predicted that we may get a storm this year. It's ...