I RECENTLY learned that the field of radio astronomy essentially started with a meteor shower. It was December 1945, and physicist Bernard Lovell was in Cheshire, UK, searching for cosmic rays 鈥� high-energy particles that zip through space. He had obtained a radar detector left over from the British army after the second world war, and a patch of land owned by the University of Manchester鈥檚 botany department.
It just so happened that the night Lovell picked to search for cosmic rays was 14 December, the peak of the Geminid meteor shower. When he turned the radar gun on, he picked up a load of fleeting signals, which turned out not to be cosmic rays, but meteors. He went on to become the university鈥檚 first professor of radio astronomy, and the Jodrell Bank Observatory now sits on the site where he first went searching.
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The Geminids are one of the most impressive meteor showers of the year, and the peak is approaching once again, on the same date Lovell was looking: 14 and 15 December. But the shower is active from 4 December, so you can keep an eye out from then.
Like all meteor showers, the Geminids are named after the constellation they appear to come from in the sky 鈥� in this case, Gemini. You don鈥檛 have to find Gemini to see the meteors, as they will travel across the sky. But if you want to, Gemini is easy to identify thanks to its two bright stars, Castor and Pollux.
First, find Orion and look for its two brightest stars, Rigel and Betelgeuse. Betelgeuse is a reddish star in the top left of Orion, viewed from the northern hemisphere, or bottom right from the southern hemisphere. The blue-white Rigel is in the bottom right of Orion in the northern hemisphere, but top left in the southern hemisphere.
To find Gemini, draw a line from Rigel to Betelgeuse, then keep that line going about the same distance again to find two bright stars close to each other, Castor and Pollux. This is where the Geminids will appear to come from.
Meteors are bright flashes of light caused by pieces of dust and rock entering our atmosphere and burning up. Many meteor showers happen at the same time each year because they occur when Earth enters a region of its orbit with lots of debris, mostly remnants of comets. The Geminids are unique because they are not by a comet but by an asteroid, called 3200 Phaethon. Strangely, the rocky asteroid has a vapour tail like comets 鈥� in 2021, NASA suggested this might be because of sodium 鈥渇izzing鈥� on its surface.
No special equipment is needed to watch the Geminids, just a clear sky. This year, there will be little moonlight in the way, as there is a new moon on 12 December. The Geminids have been known to produce up to 150 meteors an hour in dark skies. You are unlikely to see that many, but even just a few are beautiful to behold.
Abigail Beall is a features editor at New Scientist and author of The Art of Urban Astronomy. Follow her @abbybeall
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