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On a mid-November night in 1833, millions of Americans awoke to strange flashes of light. Peering outside, they discovered the night sky ablaze with meteors, pouring from the constellation of Leo at a rate of thousands to tens of thousands per hour. For many, amazement was tempered by terror -- surely the Day of Judgment was near!

A bright meteor streaks toward the horizon

Other, less well noted, but very active November meteor showers or "storms" had happened in 1799 and 1832, and still others recurred in 1866, 1867, 1900, and 1901. The approximate 33-year periodicity of these events failed in the early 1930s, but the Leonids (as they are now called) roared back to life on the morning of November 17, 1966, when more than 100,000 meteors per hour were seen from certain locales in the American Southwest.

The modern scientific explanation of the Leonid phenomenon attributes the meteors to small particles shed from a comet (specifically, a familiar one known as Comet Tempel-Tuttle) that collide with Earth's upper atmosphere in parallel streams. Each particle disintegrates in a blaze of light as it plows through the air at more than 100,000 miles per hour, appearing and disappearing from view in a fraction of a second. By the effect of perspective, the paralleling paths of these particles create the illusion that the meteors originate from a single "vanishing point" in the sky, called the shower's radiant. All Leonids radiate from Leo, a constellation that at this time of year lies above the horizon from about 11 p.m. onward.

Both the planet Earth and any stream of cometary debris must be at the same place in space at the same time to generate appreciable meteor activity -- a circumstance that occurs no more frequently than once a year, when Earth returns to the same spot on its orbital path around the sun. In the case of the Leonids, our chance of encountering a particularly dense strand of the cometary material responsible is greatly improved roughly every 33 years.

Next week, the odds are reasonably good for a repeat performance of the great meteor storms of 1833 and 1966. Intense activity is most likely to occur on the night and early morning of November 16-17, and repeat performances are possible on the same date in 1999 and 2000. Since the peak intensity of the shower tends to be short-lived, it is possible that we may miss it on account of daylight. Some astronomers believe that this year's peak will occur during the late morning hours (Pacific time) on the 17th -- good for observers in the Eastern Hemisphere who will be in darkness, but not good for us in the United States.

If the weather is fair this Monday night/early Tuesday morning, consider starting a sky-watching vigil at around 11 p.m. or midnight. Meteor rates should improve as the clock inches toward dawn, approximately 5 a.m. Any meteor watching will be enormously improved if you remove yourself from the light-polluted city and travel to dark locales such as our local mountains (Palomar, Cuyamaca, Laguna) or our local desert (Anza-Borrego).

You don't need a telescope, which would only restrict your view. Rather, simply lie back in a warm sleeping bag at any site with a relatively unobstructed view of the whole sky. And be prepared to repent.... The Day of Judgment is nigh!

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