E-Paper
4 moons appear over Russia’s St. Petersburg in rare Paraselene phenomenon | Watch
The rare event was spotted on Sunday night and quickly drew attention online. Photographs and videos of the phenomenon spread rapidly across social media.
Skywatchers in Russia's St. Petersburg witnessed an unusual celestial sight when four moons appeared in the night sky.
The rare event was reportedly spotted on Sunday night and its clips quickly drew attention online. Users shared their amazement at the glowing formation above the Russian city.
The striking sight left many stargazers stunned as bright shapes seemed to flank the Moon, creating the illusion of multiple lunar bodies.
(HT.com cannot independently verify the authenticity of the clip)
What caused illusion
The spectacle was not caused by extra moons, but by an atmospheric optical effect known as paraselenae. These are often described as “moon dogs” and are similar to sundogs, which form around the Sun.
Paraselenae occur when moonlight passes through ice crystals high in the atmosphere. These crystals are usually found in thin cirrus or cirrostratus clouds at high altitudes. Their flat, hexagonal shape allows them to bend light in a precise way, acting like tiny prisms in the sky.
How Paraselenae appear
As the light is refracted, bright spots appear on either side of the Moon, usually about 22 degrees away. These glowing patches sit at the same height above the horizon as the Moon itself. In rare cases, more than two paraselenae can be seen, creating the impression of several moons in the sky, Sky Brary reported.
The vertical size of these light spots depends on how much the ice crystals wobble as they fall through the air. Larger crystals tend to produce taller and more noticeable shapes.
When conditions are right, paraselenae can show faint colours. Red tones often appear closest to the Moon, fading outward into pale orange and blue. However, the colours are usually weak and often blend into a white halo around the Moon.
