A weird flash lit up the sky over Kyiv. NASA denied it was a falling satellite, and experts still can't confirm what caused it.

• A blinding flash of light over Kyiv on Wednesday remains unexplained. 
• Ukraine officials had originally blamed a satellite NASA that was falling back down to Earth.
• But US officials have denied the satellite's involvement, saying it was still in orbit at the time. 

The mystery over what caused a blinding flash to light up the night sky over Kyiv on Wednesday remains unsolved after NASA denied involvement. 

The flash lit up the sky minutes before the air raid alarm was triggered in the city, causing concern among residents.