A meteor shower is a phenomenon, during which a stream of interplanetary dust particles (technically known as meteoroids) crosses Earth's orbit and these particles then enter Earth's atmosphere at high speed, quickly heating up due to friction as they pass through it, evaporating and creating glowing trails behind them. We call these meteors, commonly known as "shooting stars" or "falling stars." Several meteor showers can be observed throughout the year, the most active of which are the Quadrantids in January, the Perseids in August, and the Geminids in December. The latter will peak in the coming days.

Meteors from the constellation Gemini

The name of the meteor shower – Geminids – is derived from the Latin name of the constellation Gemini, from which the meteors appear to fly throughout the entire period of activity. In the case of the Geminids, this location – known as the radiant – lies east of the two brightest stars in the constellation, Castor and Pollux. In the December sky, the constellation Gemini, including both stars, rises at dusk and is therefore visible throughout the night. In mid-December, it is highest above the horizon around 2 a.m. At that time, the radiant of the meteor shower reaches an altitude of about 70° above the horizon in our latitudes. Thanks to this, more than 140 meteors per hour can be observed in the early morning hours at the peak of the shower. Under ideal conditions, up to 1,000 Geminid meteors can be seen throughout the night during the peak. Compared to other showers, however, these are relatively slow meteors – they enter the atmosphere at a speed of approximately 35 km/s. The Perseids, for example, fly in at a speed of 59 km/s, and the fastest swarm, the Leonids, collide with us at a speed of 70 km/s.

The first reports of the Geminid meteor shower date back to 1862. At that time, however, the shower was very weak, with a frequency not exceeding 30 meteors per hour. It was not until the 1940s and 1950s that the number of meteors per hour doubled, rising to current levels until 1990. According to some models, this unstable shower is currently at its peak and its frequency will decrease year by year. By the end of the 21st century, the shower should almost disappear.

The source is a crumbling asteroid

The ice particles that create this celestial spectacle as they pass through Earth's atmosphere originate from the body (3200) Phaethon. While comets are usually the most common parent bodies of meteor showers, 3200 Phaethon is a crumbling asteroid. It was discovered on October 11, 1983, by astronomers Simon Green and John Davies using the IRAS satellite. The asteroid has an unusual orbit that takes it into the inhospitable vicinity of the Sun once every year and a half, to a distance of only 0.14 AU (astronomical units) from it. Although it has never been observed to exhibit activity typical of comets, the asteroid appears to be more like a comet. This is due to its elongated orbit, which brings Phaethon closer to the Sun than any other asteroid, and its contribution to the Geminid meteor shower. Due to the regular significant heating of the asteroid, volatile substances escape and the asteroid gradually crumbles. Some astronomers also believe that it is a fragment of the large asteroid Pallas from the main asteroid belt between Mars and Jupiter.

Since the asteroid's orbit is close to Earth's orbit and the asteroid orbits the Sun once every less than 524 days, the question of its close flyby of Earth arises. The last such flyby occurred on December 10, 2007, when the asteroid passed Earth at a distance of about 18 million km (about one-eighth of the distance between Earth and the Sun). The next close flybys will take place in 2050 and 2060. However, it will not come closest to Earth in this century until December 14, 2093. At that time, it will be only 3 million km from Earth, which is only eight times farther than the Moon. However, there is no danger of a physical collision with Earth.

Favorable conditions this year

The Geminids have favorable conditions this year. The peak is predicted for the weekend night of December 13/14, with the swarm peaking on Sunday morning. The frequency of meteors will be highest when the constellation Gemini rises highest above the horizon, between midnight and 4 a.m. When observing this year's Geminid peak, there will be almost no interference from the moon, which will be only 5 days before the new moon and will rise in the second half of the night.

The best viewing is far from cities

To observe the meteor shower, choose a location with a clear view, away from trees and buildings, and above all, as far away as possible from light pollution this will allow you to see even the faintest meteors). The phenomenon is best observed while lying down – a deck chair or sleeping mat is recommended. Don't underestimate the freezing December nights, so equip yourself with the warmest clothing, a sleeping bag, or several blankets. During December nights, you should also expect possible inversions, so it is best to head for the mountains. Nothing else is needed – meteors fly randomly across the sky. So just fix your gaze on any area of the sky and wait for the first flash.

An easy target for photographers

You can also photograph the phenomenon. However, a smartphone alone will definitely not suffice. First, you need to mount the camera on a tripod and point it at the selected part of the sky. Your camera must be able to take exposures of several seconds on a tripod (or allow you to manually control the shutter for any length of time, generally indicated by the letter "B"). If your photographic equipment meets these requirements, then all you have to do is point the lens at the sky during the night, open the shutter (or set the longest possible exposure) and wait for a brighter meteor to fly through the star field that your camera is currently capturing.

In the photograph, the meteor will appear as an uneven narrow trail of light, sometimes with occasional bright spots. Of course, a wide-angle lens can be a great advantage, as it minimizes the effects of the Earth's rotation during shorter exposures (stars will appear as points rather than small arcs) and allows you to capture a larger portion of the sky, thus increasing your chances of capturing a meteor trail. In addition to meteors, you will be able to see the bright stars of the winter constellations, the prominent star clusters of the Pleiades and Hyades in the constellation Taurus, and the nebula in the constellation Orion. You can see what the Geminid meteor shower looks like in multiple-exposure shots at this link.

Extraordinary phenomena in the coming months

Other suitable conditions for observing the swarm will occur next year. The year 2026 will also offer other interesting phenomena. Other meteor showers and possible auroras visible from our territory will also draw us to the sky. However, the main attraction will be the very significant partial solar eclipse on August 12, which will be visible as a total eclipse from easily accessible Spain. Given the location of the Czech Republic, this will be the geographically closest total solar eclipse until 2081. A complete overview of the phenomena in 2026 can now be found on the website of the Institute of Physics in Opava here.

Contact details

Mgr. Petr Horálek

RNDr. Tomáš Gráf, Ph.D.

Mgr. Simona Beerová

Press release No. 330 of December 8th, 2025, issued by the Institute of Physics of the Silesian University in Opava and the Czech Astronomical Society.