Watching the Sky Fall

It's that time of year again, folks. The Leonid meteor shower is set to peak on the (early) morning of November 17. According to a Space.com article on the shower, the most intense viewing will be in Asia. However, it is predicted that we here in the U.S. may get a decent show as well. For those of us here in the Midwest, it may not be as spectacular as what may be seen on the East coast. But I'm optimistic that crawling out of bed on a chilly Autumn night at 4 or 5 in the morning will not be totally fruitless. Although there have been a few years that the Leonids have disappointed, more often than not, they create pretty amazing displays.

The Leonids are pretty cool creatures. The particles that create the shower are dust debris from the comet Tempel-Tuttle, which are ejected as the comet is warmed by the Sun, creating a debris trail. Each year, the Earth passes through the trail and, depending on the density of the dust particles, they come zipping into our atmosphere. As they enter the atmosphere at a fairly high rate of speed, 45 miles per second, they ionize molecules in the atmosphere. The ionized molecules then relax to a resting state, but give off photons when they do so. This is what creates the bright, streaking meteoroid trail as they move across the sky. Also, because the dust particles are all moving in more-or-less the same direction in space and therefore enter the atmosphere in the same direction, they look as though they originate from a particular point in the sky. This point is called the radiant point. In the case of the Leonids, that point is near or directly over the constellation Leo, hence the name of the shower.

In the past, the Leonids have created what are referred to as meteor storms, which are unusually spectacular displays. It is thought that the exuberant display that was observed in 1833 produced in upwards of 100,000 meteoroids per hour. Unfortunately, we will likely see a number more along the lines of 25-30 per hour. But it's always possible that we could see many more than that, particularly on November 17. This is due to the fact that we know very little about the stream of debris that the Earth will be moving through.

If you'd like to view the Leonid shower, the most important step is to find a good location. You'll want to be as far as possible from city lights. If you think you'll be able to leave the city lights behind, but not travel far, you should consider traveling East since Leo, the shower's radiant point, will be in the Eastern sky. This should do well to put the interfering lights behind you, and give you a nice dark theater for watching the Leonids. Once you've got a good location, settle in, stay warm, and enjoy the show.

Not sure where Leo is, but want to know exactly where the radiant point will be? No problem. You can go to the AstroViewer Interactive Night Sky Map, punch in your location (anywhere in the midwest will work - I used St. Louis as my location), adjust the date to Nov. 17 and the time to when you plan on being out stargazing, and note the location of Leo. Good luck!