1866

Source of the Leonid Meteors

Urbain LeVerrier (1811–1877)

Go out on a clear, moonless night to a dark-sky location away from the city, park yourself down on a blanket or in a nice reclining chair, and look up. Once your eyes have adapted to the dim light of the stars, it won’t be long until—out of the corner of your eye—you spot a short, bright streak of light zipping across the sky. You’ve just seen a meteor, a tiny bit of rock or ice from space entering the Earth’s atmosphere and burning up from the friction. Often called by the misnomer “shooting stars,” a few such meteors per hour can be seen on any typical clear night. Once in a while, though, usually around the same time each year, careful and lucky observers can spot dozens or perhaps hundreds of meteors per hour—a meteor shower. And, extremely rarely, the night sky can be briefly lit by a storm of thousands and thousands of meteors per hour—a cosmic fireworks show that can rival any New Year’s Eve or Independence Day celebration.

For millennia, such showers or storms of meteors were viewed as ominous. It wasn’t until the late 1860s that astronomers were able to piece together some important clues and determine the origin of these cosmic spectacles: meteor showers are related to comets.

The key to solving the mystery was the discovery in 1866, independently in France and America, of a new short-period (33-year) comet named Tempel-Tuttle after its discoverers. Other astronomers, including the French mathematician and Neptune discoverer Urbain LeVerrier, realized that Tempel-Tuttle’s orbit was remarkably similar to the orbits of meteors often seen in the mid-November shower, which are known as the Leonids. This allowed astronomers to accurately predict the next big Leonid shower, which occurred around the turn of the twentieth century, and thus to prove that meteor showers and storms happen when the Earth passes through patches of icy and rocky debris by a comet that passed through the same part of space some time before.

In addition to the Leonids in mid-November, you can also enjoy watching the fiery demise of tiny bits of comets during the Perseid shower in mid-August (from comet Swift-Tuttle), the Orionids in late October (from Halley’s Comet), and more than a dozen other increased meteor activity events throughout the year.

An 1888 artist’s depiction of a spectacular storm of tens to hundreds of thousands of Leonid meteors per hour. This particular event was widely viewed across North America on November 12–13, 1833; similarly large numbers of meteors were reported during storms in 1866 and again in 1966.