Light sources on clouds

Lasers, searchlights, car headlights and other light sources of sufficient power can form a column of light in a dusty or foggy atmosphere, various patterns on low clouds, fog or haze. Also, the rays can highlight parts of the cloud, objects or birds, giving them bizarre shapes.

Searchlights can shine with one beam, several. They can be stationary, move, and also form spinning carousels on the clouds, which can change shape and color.

It often seems that the light source is located at the point where the beam hits the cloud, and not vice versa.

Most often, this effect is unexpected for the observer, which can be misleading about its nature.

Sometimes such spots on clouds are formed specifically and used to measure the height of the lower border of clouds. For this purpose, an installation consisting of a searchlight and a sighting device (theodolite) installed at a certain distance from the searchlight is used. A narrow beam of light is directed upwards by the searchlight, and with the help of the sight, the angle between the horizon and the direction to the center of the light spot created on the cloud by the searchlight beam is determined, and the height of the clouds is determined by it.

Also, blurry, but bright spots from the lights of the city (a certain brightly lit area or building, for example, a stadium, greenhouses, or just an actively lit part of the city) can form on the clouds.

Not only bright spots of light on clouds can be mistaken for UFOs, but also shadows on them if something falls between the light source and the cloud.