Questions remain over a huge yellow flash that lit up the night sky over Sverdlovsk, Russia a few days ago. 

Drivers posted videos of what looked like an explosion, but so far there is no official explanation. 

That has led to a slew of theories, such as military testing or ordnance disposal, a meteorite, a factory explosion, a rocket launch or even a UFO. 

The Russian military said it had nothing do with it. 

Russia Today reports that there were no rocket launches scheduled between Oct. 29 and Nov. 24. 

Astronomers say the color of the light is not consistent with a meteor and authorities say there were no emergencies reported in the area at that time.