Meteor showers are celestial events that occur when the Earth passes through streams of cosmic debris left behind by comets and, in some rare cases, asteroids. During these events, numerous meteors can be seen streaking across the sky, appearing to originate from a single point—known as the radiant.
Meteors—colloquially referred to as shooting stars—are the streaks of light we see in the sky when tiny fragments of space debris burn up in the Earth’s atmosphere at high speed.
The Draconids are an irregular, relatively quiet meteor shower that on rare occasions produces very strong activity.
The Draconids are only active for a relatively short period of time—its normal limits are between October 6 and 10, according to the Royal Observatory Greenwich in London, U.K. By comparison, many other meteor showers last several weeks.
The date of maximum activity is October 8, but meteor rates are not expected to be high this year, according to the International Meteor Organization (IMO) calendar. The light from the almost full moon will also be a big hindrance to those trying to observe the event.
“This year [the IMO] states there is no expectation of unusual activity from the Draconids, so a theoretical peak rate of 10 meteors an hour is expected, which in practice means an observer might see four,” Robert Massey, the deputy executive director of the U.K. Royal Astronomical Society, told Newsweek. “But this will be made harder by the light from the nearly-full moon, so casual observers may not notice much at all,” he said.
Tania de Sales Marques, an astronomer with the Royal Observatory, told Newsweek: “The Draconids can be bright, but it will be difficult to spot them, as the full moon will be up all night long, lighting up the sky. We’re only expecting a maximum of 10 meteors per hour in this year’s display.”
Every now and again though, the Draconids, which are best viewed from the Northern Hemisphere, throw up a surprise and produce a large number of meteors—up to 1,000 in a single hour.
“The Draconids are usually fairly quiet with just a few meteors an hour, but just occasionally put on big displays,” Massey said. “So for example in 1933 an observer at Armagh Observatory [in Northern Ireland] said they fell like snowflakes. That said, the IMO do not expect anything unusual this time.”
The best time to see the Draconids is in the evening after nightfall—this is different to most other showers, which are best seen in the early hours of the morning.
The Draconids are the result of the Earth passing through streams of debris left behind by Comet 21/P Giacobini-Zinner. This object is a relatively small comet with a nucleus that measures roughly 1.2 miles across.
“It will next pass perihelion—its closest point to the sun—in 2025, and completes an orbit every 6.6 years,” Massey said.
Giacobini-Zinner is notable for being the first comet to be visited by a space probe, when the International Cometary Explorer passed close to it in September 1985.
The rate of meteors during the peak of the Draconid shower depends upon which part of the comet’s tail the Earth passes through in any given year.
