A black shadow was photographed flying with a sword in the night sky in Beijing? Meteorological expert: "Thunderstorm single"!

　　On the evening of August 6, a rare meteorological wonder appeared in the night sky of Beijing. Thunderstorms and the bright moon shone together, pink and purple lightning alternated, and only the lightning was seen without thunder. Some citizens even photographed mysterious black shadows suspected of "flying with swords" in the clouds, which caused heated discussions on the Internet.

According to the blue lightning warning issued by the Beijing Meteorological Observatory, from the night of August 6 to 2 a.m. on the 7th, thunderstorms will occur in Chaoyang, Dongcheng, Xicheng and other urban areas, with short-term heavy rainfall and strong winds around level 7.

　That night, many citizens recorded this strange astronomical phenomenon. Meteorological experts explained that this phenomenon is due to the formation of "thunderstorm monomers". Thunderstorm monomers are strong convective weather systems that are composed of strong upward airflow, usually in diameters ranging from several kilometers to dozens of kilometers. The so-called "flying with swords" is actually a visual illusion caused by the movement of clouds after the clouds flashed in a single thunderstorm.

Regarding the phenomenon of seeing lightning but not hearing thunder, experts point out that this is a normal meteorological process. When discharge occurs inside the cloud layer, if the cloud system is thicker, the sound waves will repeatedly reflect and attenuate between the multi-layer cloud bodies, making it difficult to hear obvious thunder on the ground.