The Sasovo Explosion and Glowing Spheres

Sasovo lies in Ryazan Oblast, about 350 km southeast of Moscow. It is a town with a railway station, an oil depot and state-farm fields stretching toward the Tsna River. On 5 April 1991, 30 tonnes of fresh ammonium nitrate were brought to one of those fields as fertiliser.

The night of 11 to 12 April would end on Cosmonautics Day. The 30th anniversary of Gagarin's flight.

It began at 21:20. A bright white glowing sphere appeared at the station. Locomotive driver Ivan Kurtsatov saw it. Some witnesses said it had a blue tint. It moved slowly toward the northeast.

Station workers and a large number of passengers saw huge white glowing spheres. Others described large glowing spheres of blue and red, with flashes of the same colours moving across the sky. One newspaper later wrote that the witnesses numbered "not dozens but hundreds." Half an hour before the explosion, people on the outskirts saw two bright-red spheres. Radio receivers filled with noise until every station was jammed.

Then came a sound like a plane flying directly overhead. Anatoliy, of Shatskaya Street, remembered: "I heard the sound of a plane and saw a blue flash." Ivan, near the meat-processing plant, saw "a ball coming from the direction of the oil depot, with a crimson trail behind it."

A flash lasting several seconds. Thunder. The ground was heaving. Buildings swayed and chandeliers broke. Writer Vladimir Khomyakov recalled: "As if everything suddenly collapsed, and then a receding rumble." People ran into their yards shouting "UFO!"

Outside the town lay a crater 28 meters across and about 4 meters deep, with a 1.4 meter mound on its floor. Windows were knocked out, "even the frames," in a good half of the apartment blocks. Four people were injured. Yet the damage was patchy. A tree 10 meters from the epicentre was unharmed. The oil depot and a cowshed 150 meters away were untouched. Three or four minutes after the blast, a bright red glow began to come from the crater. It lasted two days.

In 1992 a second crater was found in a maize field near Frolovskoe. Nobody heard that explosion.

Scientists, military and security staff cordoned off the crater almost at once. On 15 April 1991, Moskovskaya Pravda reported that the military had seen no unidentified objects over the area and that experts found no change in radiation levels. FBIS translated the article, and it later surfaced in the CIA's UFO collection as "Diverging Opinions on Cause of Sasovo Explosion." Military experts found no bomb residue or shrapnel. Geophysicist Yevgeny Borkovsky worked in Sasovo for almost two years and concluded that it had been a very shallow earthquake linked to deep faults.

The fertiliser was the first suspect. Critics pointed to intact sacks, no burn marks and no fertiliser near the second crater. A. Yu. Ol'khovatov proposed a tectonic explosion and read the spheres as earthquake lights. Vladimir Larin, Nikolay Larin and V. L. Syvorotkin argued for a burst of natural hydrogen. Others suggested a meteorite, a military accident or a UFO. A Soviet "UFO crash" chronology listed Sasovo, but its compiler, Anton A. Anfalov, later called it an "absurdous and wrong list." None of the theories has been fully confirmed.