Enlarge image

A shooting star can be seen during the Geminids over Lake Kochel in Bavaria (archive image)

Photo: Matthias Balk / dpa

You need a warm jacket – and a good portion of luck to break up the clouds. This year, the Geminids' shooting star swarm reaches its peak on December 14 at around 20:00 p.m. And if you are actually under a clear sky, you can look forward to spectacular observations.

Although they are among the largest shooting star swarms of the year, the Geminids are usually overshadowed by the much better known Perseids, which light up the August sky every year. However, the fact that the Geminids are less popular is mainly due to the season of their appearance. The cold and often gloomy December weather offers shooting star hunters worse viewing conditions than the balmy Perseid nights in summer.

At least the moon does not interfere with the observation of the Geminids this year. According to the Association of Stargazers, the frequency generally increases over the course of the night, which is why they are easy to see throughout the night. Under dark skies, observers can see about 50 meteors light up per hour.

Named after the constellation Gemini – Gemini in Latin – experience has shown that the swarm produces many bright shooting stars. Although dark places far away from the light-flooded cities are best suited to observe the pre-Christmas sky speedsters, the brightest Geminids can also be seen in the city sky. If you want to photograph the meteor shower, you should mount a camera with a wide-angle lens on a tripod and choose a long exposure.

Broken asteroid creates a trail of dust

The sniffles originate from a cloud of dust that crosses our earth every year at the same time on its orbit around the sun. In the process, the dust particles enter the Earth's atmosphere, where they then produce the luminous phenomena known as shooting stars.

In the case of the Geminids, however, the origin of this dust cloud is unusual. Typically, meteor showers originate from tiny remnants of comets – tail stars that release dust as they approach the hot sun, which then spreads across the comet's orbit. For example, the origin of the Perseids lies in the cosmic dust trail of comet Swift-Tuttle, which visits the Sun about every 130 years.

The Geminid dust cloud is different: it does not originate from a comet, but apparently goes back to a small asteroid – i.e. a rather solid small body in our solar system. Its name is Phaeton and it was only discovered in 1983. In fact, the dust trail was only photographed for the first time in 2019.

The exact procedure is still being discussed

It is possible that this asteroid broke up, leaving debris on its orbit, which burns up as shooting stars as it enters the Earth's atmosphere.

Scientists disagree on how a rocky body can release particles. The latest theory, however, is that the body's close proximity to the Sun is the cause. The thermal stresses are supposed to cause cracks, so that particles eventually split off.

The Geminids have other peculiarities. Thus, the meteors of the stream move comparatively slowly across the sky. The reason for this is the low speed at which the Geminid particles plunge into the atmosphere. It is 122,000 kilometers per hour, compared to 212,000 kilometers per hour for the Perseids.