About 100 tons of extraterrestrial material fall onto Earth every day, most of it dust. When extraterrestrial objects enter the Earth’s atmosphere at high velocity, their surface is strongly heated and the surrounding air molecules are ionized, forming a plasma trail at altitudes between 120 and 80 km.

Thus, shooting stars form by producing a trail of light, which is actually ionized air, as they burn up in the atmosphere, whereas fireballs are caused by larger fragments of extraterrestrial material. In general, these short-time light phenomena are called meteors.

Meteors are commonly seen with the naked eye, best visible during the night, and can be detected using video cameras, such as surveillance cameras or specific fisheye cameras.

Only extraordinary large events can also be seen during daytime, as, for example, on February, 15th, 2013, when a 20 m diameter asteroid exploded over the Chelyabinsk area in Russia.

Because plasma trails reflect electromagnetic waves at radio frequencies, meteors can be detected during the day and night and in all weather conditions, using a low-frequency radar.