The Leonid meteor shower, which peaks this week in the early morning of November 17, has in the past offered stargazers the most reliable opportunity to see a spectacular celestial event. The Leonids haven’t been much to look at in recent years, however, and experts predict this yearʼs Leonids will be quite tame. But there have been some astonishing historical outbursts during the Leonid meteor shower, including one in the 19th century that changed our understanding of where meteors come from…
The great Leonid meteor storm of 1833 was perhaps the most spectacular in recorded history. Visible from eastern North America, the storm produced as many as 200,000 meteors per hour, startling 19th-century observers into a glazed stupor or near-catatonic terror. Nearly everyone awakened to see the bright meteors and attending commotion on the morning of November 12. The storm lasted nearly four hours. According to astronomer Agnes Clerke, “the frequency of meteors was estimated to be about half that of flakes of snow in an average snowstorm”.
The meteors came so quickly during this 1833 storm, it was clear the radiant, or apparent source, of the meteors lay towards the Sickle of the constellation Leo. And the radiant moved with the stars during the evening, which finally made it clear that meteors came from outside the Earthʼs atmosphere. Until then, some believed meteors were an atmospheric phenomenon, the belief of which lent the term “meteorology” to the study of the weather.
Astronomers looked at historical records to determine the Leonids peaked at multiples of 33 years… in 1799, 1533, 1366, 1202, and 1037, for example. We now know the peaks correspond to brief periods during which Earth passes through a concentration of debris left in the path of Comet Tempel-Tuttle. The Leonids last peaked in 1999, with bonus peaks in 2001 and 2002 (though they did not approach the dramatic peak of 1833). No peaks are expected in the coming years, but the Leonids have been known to surprise to the upside!