Image at top: Draconid meteor seen in 2011 by Frank Martin Ingilæ. Used with permission.
These next few evenings – October 7 and 8, 2018 – the fiery mouth of the constellation Draco the Dragon will be spitting out meteors, also known as shooting stars. The Draconid shower is predicted to produce the greatest number of meteors on the evening – not after midnight – on October 7 or 8. This shower favors the Northern Hemisphere. Just be forewarned. Even at northerly latitudes, the Draconids are typically a very modest shower, perhaps offering only a handful of slow-moving meteors per hour. But watch out if the Dragon awakes – which it might this year, given that the parent body of this meteor showerc Comet 21P/Giacobini-Zinner, is near perihelion – its closest point to the sun in its orbit!
The Draconid meteor shower produced awesome meteor displays in 1933 and 1946, with thousands of meteors per hour seen in those years. Seven years ago – in October 2011 – people around the globe saw an elevated number of Draconid meteors, despite a bright moon that night. European observers saw over 600 meteors per hour in 2011.
The Draconid meteor shower might offer an elevated number of meteors in 2018, too. To reiterate, that’s because the parent body of the Draconids, Comet 21P/Giacobini-Zinner, reaches perihelion – its closest point to the sun in its orbit – less than one month before the expected peak of the Draconid shower. But you never know for sure with the Draconids, so it’s worth watching out for on the evenings of October 7 and 8. Just know that meteor showers are notorious for defying predictions, either surpassing or falling shy of expectation.
The only way to know for sure is to try to watch the shower.
Luckily, watching the shower is lots of fun, even if you see only a few meteors. Just plan to spend an hour or more under a dark and open sky, lying down and with your feet pointing northward.
Most meteor showers are best after midnight, but this shower is different, best viewed in the evening hours. Watch for the Draconid meteors first thing at nightfall. Best of all, there is no moonlight to ruin the show in 2018.
Can you see the Draconids in the Southern Hemisphere? Click here for all you need to know about this shower.
Most meteor showers are named for the constellation from which the meteors radiate on the sky’s dome. The Draconids, however, are sometimes also called the Giacobinids, to honor the man who first sighted the comet that spawned this meteor shower. Michel Giacobini discovered this comet on December 20, 1900. Another sighting in 1913 added the name Zinner to that of the comet, which thus became 21P Giacobini-Zinner.
Giacobini-Zinner is a periodic comet, which returns every 6 years and 4 months. Tracking this comet, and noting this October meteor shower, helped astronomers figure out how to predict meteor showers in 1915.
For a taste of history related to this shower, go to the Astronomy Abstract Service from the Smithsonian and NASA and find a 1934 article called The Meteors from Giacobini’s Comet by C.C. Wylie.
It’s a fascinating account of the famed meteor storm of 1933.
Now let’s consider the great Draconid/Giacobinid meteor storms of 1933 and 1946, and that of 2011, when observers in Europe saw over 600 Draconid meteors per hour. Why was the meteor shower so good in 2011? Why do we see more meteors in some years than in others?
The answer is that Comet Giacobini-Zinner was at perihelion – closest to the sun – in 2011. Meteors are debris from comets, so when a parent comet is nearby, a good meteor shower is possible.
It doesn’t always happen, though. The comet returned in 1998, and the Draconids did pick up that year, but only to a rate of about 100 per hour.
So there you have it. Meteor showers are part of nature and not entirely predictable. Under normal conditions, when astronomers speak of a meteor shower peaking, it’s similar to a weather forecaster saying:
The heaviest rain/snow is predicted for 9 p.m.
That prediction isn’t a certainty. It’s more like an educated guess, and it might not come to pass. Or it might happen for you, but not for people across town. It’s a good analogy to the 2011 Draconids, which were best seen over Europe but less good, for example, over North America.
Bottom line: In 2018, the Draconid meteor shower – also called the Giacobinids – will probably be at its best on the evening of October 7 or 8. No need to wait until after midnight; the radiant is highest in the evening hours. No one expects a Draconid storm this year, but it’s fun to watch and see. Clouded out for the Draconids? Didn’t see a thing? No worries. Meteor season ahead! Check out EarthSky’s 2018 meteor guide.