Where they come from
The Leonids stem from debris left behind by comet Tempel-Tuttle, which orbits the sun every 33 years. Leonid meteors zip through the sky comparatively fast — close to 45 miles per second. That helps boost their colors, with occasional larger chunks of celestial debris making for desultory bright fireballs. The Leonids may make a few nightly appearances for most of November, but the shower tends to peak annually around Nov. 17.
What to expect this year
A moon roughly two-thirds illuminated Monday won’t cooperate with intrepid viewers willing to brave a wintry chill. Already pale meteor rates will be slashed in half, the fainter streaks of light washed out by the glaring moon. Realistically, you’re likely to only witness half a dozen or so Leonids per hour at best this year.
Of course, even a single meteor can be memorable if it happens to be a fireball. NASA’s All-Sky Fireball Network, an array of 17 cameras across the eastern third of the nation and the desert Southwest, captured 15 bright fireballs Saturday night into Sunday morning.
Thousands of meteors per minute: What makes a Leonid ‘meteor storm’
Though this year’s display is tame, past episodes of the Leonid meteor shower have not been. The nominally dormant spectacle has been known to produce sudden spikes of extreme activity, with meteor rates closing in at 100,000 meteors per hour or more.
The first inklings that something extreme was lurking within the Leonids came in 902 AD, when astronomers in China and northern Africa recorded accounts of stars falling “like rain.” A few additional meteor storms are rumored to have occurred during the next nine centuries, though evidence to support such claims is largely anecdotal. Another potential meteor storm was sighted in the skies over present-day Venezuela in 1799.
But in 1833, the sky exploded. “At Boston, the frequency of meteors was estimated to be about half that of flakes of snow in an average snowstorm” wrote Irish astronomer Agnes Mary Clerke, who stated that the storm lasted about nine hours. Clerke placed estimates of meteor rates at the unheard of — as many as 240,000 shooting stars per hour. That’s more than 60 shooting stars per second.
Denison Olmsted, a Yale science professor at the time, was awakened by an unexpected brightening of the night sky, his neighbors rushing outdoors to stare at the sky in wonder. He charted meteor rates of 20 or more per minute.
A NASA write-up noted that people in the District were frightened “half to death.”
The Leonids again dazzled on the night of Nov. 13-14, 1866. One newspaper in Malta published an eyewitness report describing the scene as “truly grand and imposing … one of the most sublime that I ever beheld.”
Another meteor storm came in 1966, igniting an equally splendid fireworks show in the United States. Eyewitness Christine Downing, who drove north of Mojave, Calif., saw a couple of shooting stars every five minutes, which “at the time … seemed extraordinary.” At 12:30 a.m., it began “raining stars,” and by 2 a.m.. “it was a ‘blizzard.’ ”
Her description, which can be read in full on a NASA Web page, is one of many from that night. “There was the unnerving feeling that the mountains were being set on fire,” Downing wrote. “Falling stars filled the entire sky to the horizon, yet it was silent.”
Ralph Petrozello was 15 at the time and experienced the meteor storm in Binghamton, N.Y. “When we looked up there appeared to be hundreds meteors [coming] out of one point in the sky!” That point is the radiant. Petrozello described the lone dark patch from which the meteors appeared to emanate as resembling “the inside of an enormous cone.”
When is the next storm?
Predicting such a fickle yet otherworldly visitation is no easy task. Meteor storms happen when a very narrow but extremely dense pocket of cometary debris spatters against Earth’s atmosphere, like a vehicle driving into a swarm of mosquitoes.
Russian astronomer Mikhail Maslov anticipates that a “number of outbursts” can be expected in 2034, with rates topping 500 meteors per hour. That’s far from a meteor storm but still a good show.
The next Leonid meteor storm, however, isn’t likely until 2094.