Every 33 years, Comet 55P/Tempel-Tuttle makes its closest approach to the sun; it is one of a handful of comets that can be seen more than once in a person’s life. Tempel-Tuttle’s most recent visit to the inner solar system was in March 1998.

As each comet approaches the sun, the energy from our star burns off material from the comet, creating the famous bright appearance and cosmically long tail that we see with every comet (these phenomena are on display this week with the approach of Comet ISON). This material, mostly particles the size of grains of sand, is left behind in space. Every time Comet Tempel-Tuttle starts its disintegration, the process happens at around the distance of earth’s orbit, so a cloud of dust is left behind for us to crash through every year. This is the Leonid meteor shower. Every November 18 or so, we cross through…