Stunning apocalypse scenes, as night turned to day in southern districts of the Republic of Khakassia.
Flash seen over thousands of kilometres but scientists disagree over the cause.
As usual there is outlandish speculation about an alien visit, but there is genuine puzzlement and disagreement among experts over the mystery object.
Emergency services refuse to comment cause of extraordinary blast in the dark sky.
Sensational pictures of last week's meteorite strike have emerged from a Russian photographer.
A meteor? A rocket? A military missile? An UFO? So far no explanation for the lightshow over Trans-Baikal.
As footage emerges of more unexplained explosions above Siberia, suspicion falls on recycling of gunpowder at old chemical plant.
The sensational discovery could lead to a much clearer understanding of a blast which was 1,000 times more powerful than the Hiroshima bomb.
Spectacular falling meteorite fragments struck the Chelyabinsk region on Friday morning exploding in the atmosphere and crashing to the ground.