What are the rare astronomical wonders?

On a sunny day, there was a sudden darkness? It was neither a solar eclipse nor before a tornado. Although it is a regional temporary situation, this phenomenon has happened many times at home and abroad?

On an autumn afternoon in Bangui 1944, China, the clear sky suddenly became dark and opaque? People panicked and shouted that the sky was falling? It took about 1 hour to restore the light, and people gradually calmed down?

There is a strange phenomenon in Qingdao. Night falls during the day? One morning 1 1, the sky radiated by the sun became darker and darker, and the clouds were overcast. At 12, the dark clouds were overwhelming, and the world was dark, stormy and thunderous. Many pedestrians were caught off guard and fled to the shops along the street? Suddenly, the street was "brightly lit", street lamps were put together, and the lights of passing vehicles were turned on? This phenomenon lasted for more than half an hour?

On the morning of May 1980 in New England Reclamation Area, USA, people were busy going to work as usual? In the morning 10, it suddenly got dark, as if it had entered the vast darkness, and everyone was frightened? This scene lasted until dawn the next day?

Besides, in Preston, England, there is darkness during the day? 1On April 26th, 884, the sky turned from gray to dark, and it was getting dark? It took about 20 minutes for the sun to shine.

According to people's memory at that time, nothing unusual was found before this dark phenomenon appeared during the day, and all this happened suddenly?

Why is there such a celestial phenomenon? So far, scientists have different opinions, and some say it is related to volcanic eruption; Some people say it is probably related to visitors from other planets, who crossed the earth and then left quietly, forming a temporary darkness somewhere on the earth?

So far, scientists have not studied this astronomical wonder further? Discuss?