Things sometimes flash in the night sky. That includes some weird and wonderful astronomical objects. Some of them shine for a few minutes or even seconds, then vanish. So it can be tough to understand just what caused them.

Thousands of these “transients” showed up in a decade-long look at the night sky. And a recent study found a statistical link between some of those transients and both nuclear weapons tests and reports of UFOs.

The study analyzed thousands of nights of observations by the Palomar Sky Survey. From 1949 to 1958, astronomers repeatedly photographed the night sky on glass plates, looking to compile the best map of the heavens to date. Many of the plates revealed transients that were star-like pinpoints of light.

They appeared out of nowhere, then disappeared just as quickly.

The study found that, on average, the number of transients was greater on nights just after above-ground nuclear explosions. And there were more reports of UFOs on nights with more transients.

There are many possible explanations. There could be problems with the original plates, for example. The nukes could’ve created some previously unknown effects in the atmosphere. The study also says the flashes could have been metallic objects far above our planet – perhaps even visitors from other worlds.

But many scientists say we need a much more thorough look at the pictures before we’ll know what caused these flashes in the night sky.

Script by Damond Benningfield