A large, blue fireball lit up the sky above Sweden last Monday night. Residents of Uppsala, Örebro, and the Swedish capital, Stockholm, all reported a bright blue flash in the night sky. Eric Stempels, from the Department of Physics and Astronomy at Uppsala University, has reassured the public that the fireball was harmless, and that this phenomena is perhaps more common than people think.

"This was something very small that does not pose any threat to us,” said Stempels. "This is something that happens a few times a year."

"Because it can happen during the day, when it is cloudy or far from populated areas, these events usually don't get much attention.”