October is all about Draco but there’s no Harry Potter in sight!
2nd October
One of the regular and easy ways to take part in watching the universe is too look for meteors. Science can use them to survey the content of the solar system, technology can use them to build and test strange radio equipment and the rest of us can enjoy the free show. If you ever wondered where JK Rowling’s Harry Potter character got his name then here is the answer.
In October one of the lesser meteor showers is the Draconids named after the constellation Draco from where the meteors seem to fall. Draco is the dragon of legend, that defended the golden fleece, was fought and slain by Hercules who lies next to it in the sky and who was and then cast into the sky to spin forever around the sky.
Despite its might of legend this is a quiet dragon and the constellation contains few bright stars that make it easy to find. It is easier to find it by looking for the gap between the brighter constellations around it.
Similarly this is no fire breathing dragon when we study the meteors. In most years this is one of the quietest meteor showers with only some 20 or so meteors every hour. Exceptions to the low rates seem to occur every six or seven years. 1998, 2004 and 2011 were all unusually active with rates up to 700 meteors an hour so 2018 is worth watching. Just like the weather on Earth is unreliable meteor showers are similar unreliable but the small hours of the night of 8th – 9th October with the moon out of the way offer the best chance.
One feature of the Draconids is that in the past they have shown much more likelihood of reaching lower heights before disintegrating and even more chance of making all the way to ground, albeit that such a chance is still infinitesimally small. When they do reach to the ground they give us a chance to study space without having to visit it. Despite being from space and probably from comets that exhausted their lives as comets long ago these can often be surprisingly like the samples we find from asteroids and indeed we now think that a surprisingly large proportion of the asteroids are extinct comets.
Other meteorites are surprisingly wide ranged in their origins and astronomers have become quite adept at identifying the origins of meteorites when found upon the Earth. We can now recognise when the meteorites we find upon the Earth have come from asteroids (most commonly the asteroid Ceres), the moon and even Mars. In the case of the Moon we have the good fortune to be able to make a direct comparison with samples returned by the Apollo missions.
This month as part of the Observatory’s Introductory Astronomy course we have the good fortune to be able to borrow meteorite and moon samples courtesy of NASA.
Thank you to Jarvis Brand for this fascinating article. Jarvis is a regular contributor and runs the planetarium for the Observatory Science Centre, he can be contacted on planetarium@the-observatory.org or on 01323 832 731.
The Observatory Science Centre will be open every day throughout October. The introductory astronomy course is run every year in September to November and regularly features a section when moon samples are borrowed from NASA. An intermediate astronomy course is run every year in February to March.
