The skies will light up with a meteor shower. (Scott Cramer/Getty Images)
Conditions are ripe — that is, identical to the conditions that spawned it the last time — for a meteor shower so rare it has not been seen since 1995.
The rogue shower, dubbed the Unicorn both because of its infrequency and for the constellation from which it appears to emanate, might grace our skies Thursday night into Friday.
Views will be best in eastern South America and parts of Africa, but with good viewing in the Northeastern and midwestern U.S. The farther west one goes, the more into the “possible” it veers. Sky and Telescope mapped out the odds for potential viewers.
It’s called the Alpha Monocerotid shower, emanating as it does from the constellation Monoceros the unicorn, and it has only appeared four times that we know of: 1925, 1935, 1985 and 1995, according to the American Meteor Society.
Unlike other showers, which build over several days with an hours-long peak, this one will burst upon us in a hail of something resembling sparkling buckshot during just 15-40 minutes starting around 11:15 p.m. Thursday, which is when Sky and Telescope recommends star gazers be outside, looking east.
“For East Coast observers, the peak should come at 11:50 p.m.,” the Farmer’s Almanac said in a statement. “Meteor activity should quickly rev-up after 11:30 and conceivably could be all but over by 12:10 a.m. It will be that quick.”
Peter Jenniskens, a senior research scientist at the SETI Institute and NASA’s Ames Research Center, and Esko Lyytinen of the Finnish Fireball Network are predicting a potential firestorm, with 400 meteors per hour — which boils down to about seven per minute, though they are not spaced out evenly.
“Periods only 5 minutes from the time of the outburst could see considerably less activity,” the AMS said. “These meteors are never spaced evenly but appear in bunches so two or three meteors may be seen seconds apart, and then an entire minute could go by without any activity. This is still far and away extraordinary activity.”
Another distinction between this and other showers is that with this one, the comet from which it originates is not known.
“These outbursts are caused by the dust trail of an unknown long-period comet,” Jenniskens and Lyytinen told Earthsky.org. “Dust was released during the previous orbit of the comet, when it was last near the sun. Some meteoroids made a short orbit and came back early; others made a wider orbit and will come back later. So, in the path of the comet now is a stream of meteoroids, quite smoothly distributed.”
The first three times this shower exploded up above were a surprise. But by the time the 1995 shower came along, astronomers were prepared and had mapped out the exact point in the sky that the shooting stars would radiate from, known as the radiant, and even videotaped the encounter, the meteor society said.
Moonlight will not be a problem, since the moon won’t come up until after 2 a.m. Friday, long after the skies have stopped sizzling.
That stream of mystery-comet dust moves in and out of Earth’s orbital path, Jenniskens and Lyytinen said, which is the reason the shower hardly ever makes an appearance. It takes the dust trail wandering into Earth’s path just as our planet passes through it to make such a shower.
The rubble trail is “dense, but exceedingly narrow,” says Space.com, with meteoroids slamming into Earth at 41 miles per second.
“If nature is in a show-off mood, you might end up seeing dozens of shooting stars to wish on,” the Farmer’s Almanac said. “If the display falls short, and you don’t try too desperately hard, you might still come away seeing one or two really beautiful meteors.”
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