Rare spectacle over Stockholm: Venus dazzles in unusual green flashes

These green flashes from Venus are considered rare, similar to unicorns in astronomy. While many night sky observers may have heard of them, very few have had the opportunity to witness them. This month, however, these flashes were captured by a resident of Southern Sweden.

According to Peter Rosen, the man behind the sighting, he initially intended to observe the moonrise over Stockholm on a January morning. Nevertheless, he happened to look at the sky a bit too early and instead caught Venus emitting some unusual green flashes.

The northern European sighting facilitates arguably the best image of the aforementioned green flashes from Venus worldwide. This is an infrequent event, not because it happened to Venus specifically, but because it is more commonly associated with sunrises, where light from the sun refracts in the Earth's atmosphere, creating the green flash effect.

Although it might look unsettling, the green hues accompanying celestial bodies when low over the horizon are entirely consistent with the laws of physics. Although we perceive visible light as white, it is, in fact, a mixture of different colored beams. When such mixed light passes through the Earth's atmosphere, airborne particles can refract or bend its colors.

This effect is further intensified at lower altitudes, where the Earth's atmosphere can act like a prism. This region is rich in pollutants and often has local clouds composed of ice particles. As a result, Venus, hanging low above the horizon, was incredibly bright not only due to its position but also because the composition and lower temperatures of the atmospheric air played a crucial role.