Over the next few months, as winter wanes and the night air warms up enough to be comfortably breathed, it’s time to stand in the garden and watch the sky fall.
It’s not difficult to see how meteoroids got their nickname of shooting stars, even if the term couldn’t be less accurate. These lumps of icy gravel (cast-offs from comets powering around our solar system) rain against our planet in a slow, steady drizzle for much of the year, and unless you are remarkably lucky, there’s not much to see. But every few months, the earth passes through the dusty trail of a fragmenting comet – and we’re treated to the celestial firework display known as a meteor shower.
It’s the perfect excuse to grab a warming drink, wrap up well, and sit – or even lie – in your back garden until your eyes become accustomed to the dark. Because meteoroids move on parallel paths, they appear to be radiating from the same point of the sky – it’s the same perspective trick as when you are standing on railway tracks that seem to converge in the distance. Watching for meteors is a job for the more light-sensitive corners of your eyes – most of the time all you’ll glimpse is an after-image of a livid scratch of light across the dark sky, on the very edge of your perception. It’s hypnotically calming and it hones your senses.
So what can we expect from meteor showers in 2009? The best displays for North American observers are:
The Lyrids (mid April).
The Perseids (early August) – the most famous, and often the most beautiful.
The Orionids – caused by the passage of Halley’s Comet, and streaking across the sky in late October.
The Leonids (mid November) – spectacular in history, and a little unpredictable (although the heaviest storms come in 33-year cycles). Remarkable images include this one taken from an aircraft at 40,000 feet.
The Geminids (mid December). Appearing to fly out of the constellation Gemini (hence their name), the rather weird Geminids are regarded as one of the meteor-shower highlights of the year.
For the hardened stargazer, there are other less easily-spotted showers to tax the senses – SkyTour lists the full 2009 itinerary. And as eccentric as it may seem, reclining on the ground is a good way to watch – no amount of yoga (or mulled wine) will unkink the crick in your neck from a long, mesmerized night of craning your head back.