The Geminidas meteor shower, considered one of the most intense of the year, began this Wednesday, December 4, 2025. The phenomenon remains active until December 20, with the peak of activity expected for the night of December 13 to 14.
During its peak, observers in dark places can record up to 150 meteors per hour under ideal conditions, the second highest annual rate after January Quadrântidas. The almost total absence of the moon on the night of the peak favors the visibility of the weakest meteors.
The meteors appear to radiate from the constellation Gêmeos, close to the star Castor, but can appear anywhere in the sky.
Origin of the phenomenon
The material that generates the Geminidas comes from the asteroid 3200 Phaethon, a rocky object measuring around 5 km in diameter classified as a “blue asteroid” because it reflects more blue light than most.
Unlike most meteor showers, which originate from comets, Geminidas are produced by debris from an asteroid. Phaethon has an orbit that is very close to Sol, which causes the release of particles over time.
These particles collide with the Earth’s atmosphere at approximately 35 km/s, a speed slower than that of other showers, which makes the Geminidas meteors generally brighter and longer lasting.
When and where to observe
The shower’s radiant – the point from which the meteors appear to originate – rises in the eastern sky after sunset and reaches its highest position around 2 am.
The best observation window occurs after 10pm on the 13th until dawn on the 14th, when the radiant is high and the sky remains dark.
- Locations with little light pollution significantly increase the number of meteors visible.
- The moon in its waning crescent phase only rises around 3am-4am in the morning of the 14th, leaving the first hours of the night completely dark.
Practical tips for seeing the Geminidas
Choose a location away from artificial lights, preferably in rural areas or parks away from cities.
Take a reclining chair or mat to observe comfortably lying down, looking towards the zenith or slightly towards Gêmeos.
- Wear warm clothing, a blanket and a hot drink, as temperatures drop a lot during the early hours of December.
- Give your eyes at least 30 minutes to fully adapt to the darkness and avoid looking at cell phone screens.
Characteristics of meteors
Geminidas meteors usually have a yellowish or greenish color and moderate speed compared to other showers.
Many leave persistent trails lasting a few seconds, making photography easier.
Bright balls, known as fireballs, are relatively common in this rain, and can be seen even in areas with moderate light pollution.
How to photograph the rain
Use a camera with manual control and a wide-angle or fisheye lens.
Set ISO between 1600 and 6400, widest aperture possible (f/2.8 or smaller) and exposures of 15 to 30 seconds.
Mount the camera on a steady tripod and shoot continuous burst or use interval shooting to capture as many frames as possible during the night.
Forecast for the southern hemisphere
At Brasil, the radiant rises to a reasonable altitude in the regions Sudeste, Centro-West and Sul, allowing good observation after midnight.
In regions Norte and part of Nordeste, the radiant is lower on the horizon, reducing the number of meteors visible, but it is still worth trying in dark places.
The peak occurs during the Brazilian summer, with nights generally warmer than in the northern hemisphere, facilitating long observation sessions.
