It’s a meteor shower you’ve probably never heard of: the Alpha Monocerotids. Most years feature a trickle of meteors, with maybe three or four per hour visible during its annual Nov. 21 or 22 peak. But this year, meteor rates could spike 100-fold. A “short-lived outburst” is forecast for Thursday around 11:50 p.m. Eastern time.
If this meteor shower reaches its potential, a burst of 100 or so meteors could streak across the sky, anytime between 11:30 p.m. Thursday and 12:10 a.m. Friday.
This episode will be unlike most meteor showers, which typically peak over several days. And unlike the reliable Perseids (August) or Geminids (December), the hefty meteor rates advertised with this shower aren’t a surefire deal.
Who can see it?
Sky & Telescope reports that the meteors will originate low in the sky in the eastern United States and Canada.
“South Americans have the best seats while skywatchers in northern Africa and Western Europe will catch it in the hour or two before dawn,” it wrote.
For those in the western United States, the radiant point ― from which the meteors appear to emanate — remains below the horizon during the time of the predicted outburst, squashing any chance of seeing anything more than a few background shooting stars.
A gift from an unknown comet
The prediction of an outburst comes from NASA research scientist Peter Jenniskens and Finnish Fireball Network’s Esko Lyytinen and was published in MeteorNews. The pair specialize in sniffing out meteor outbursts and storms, expertly calculating the orbits of celestial bodies that give rise to meteor showers. Scientists still haven’t pinned down the object depositing the debris anticipated to trigger this display.
However, outbursts in 1925, 1935, 1985 and 1995 offered enough information for the team to produce a model. It indicates the close passage of a dense pocket of space-borne debris. That narrow but potent debris stream is likely to manifest in a 15- to 40-minute barrage of meteors around 11:50 p.m. Eastern time Thursday, according to the researchers.
Jenniskens and Lyytinen indicate that events in 1985 and 1995 produced 700 and 400 meteors per hour, respectively, and wrote that this event could emit anywhere from about 100 per hour to even more than 1,000 per hour, the latter considered a meteor “storm.”
The outburst is calculated to last a fraction of an hour, so those numbers can be sliced in half. And because the radiant point of the meteors will be comparatively low in the sky, we can trim off a bit more. Plus, “zenithal hourly rate” is an idealized number, realistic only if you’re in the best, darkest and clearest places on Earth and have eyes that can scan the entire sky at once.
But assuming you’re beneath dark skies with an unobstructed view (and that the outburst materializes as predicted), you could spot two or three shooting stars per minute — still highly impressive rates.
Uncertainty and skepticism
NASA, however, has expressed skepticism that the meteor outburst will materialize at all. Bill Cooke of NASA’s Meteoroid Environment Office noted that these sorts of predictions usually are accurate in regard to timing. But, he said, such predictions “often estimate a shower intensity higher ... than what actually takes place.” He thinks there won’t be any outburst at all. “Even if there is, it won’t be as impressive as many think.”
Assumptions made about the instigating comet’s orbit — a comet that astronomers know next to nothing about — mean any slight miscalculations could result in Earth entirely missing the debris stream forecast to give rise to the outburst. “Since we have not yet discovered this mysterious parent comet, who knows how close the estimate of the orbit is to the actual?” Cooke asks.
Subsequently, what folks in the eastern half of the nation see tonight could range from nothing to a decent little sputtering of shooting stars. It looks as if we’ll have to wait and see.
How to watch
Lyytinen and Jenniskens recommended starting the observations “at the latest” at 11:30 p.m. and urged folks to venture outdoors even sooner, around 11:15 p.m., just to be on the safe side. “Anyone who is going to try to observe should not be late at all,” they wrote.
Fortunately, the moon should cooperate, remaining concealed below the horizon until 12:55 a.m. (long after the shower has ended) and keeping skies dark for optimal viewing.
To witness the possible spectacle, your best bet is to bundle up and head outside a bit before the wrap-up of the 11 o’clock news. No telescopes or equipment are required; just escape city lights, avoid looking at your phone screen, and give your eyes a few minutes to adjust.
A clear, unobstructed view of the eastern sky is most prudent, since the radiant point of the shower will be rising in the east.
Sky conditions are likely to be more favorable for viewing in the Southeast, where partly cloudy skies are expected, but potentially a bit more problematic in the Northeast and Midwest because of predicted cloud cover.
How rare are outbursts?
Beyond an outburst, periodic “meteor storms” can grace the planet a few times a century. The last prolific one, which lasted about 90 minutes, occurred during the Leonid meteor shower on the morning of Nov. 17, 1966. While day was dawning on the East Coast, 40 or more meteors per second were streaking down from the heavens in the West. An even more impressive episode occurred in 1833. Unfortunately, no such storms are anticipated in our lifetimes.
The next outburst from the Alpha Monocerotids shower is predicted in 2043.
Jason Samenow contributed to this report.