A surprising discovery of gamma rays could shed light on the cosmic mystery

Astronomers have discovered an unexpected and unexplained phenomenon outside our Milky Way Galaxy that emits high-energy light called gamma rays.

The team behind the discovery, including NASA and cosmologist Alexander Kashlinsky of the University of Maryland, found the gamma-ray signal while sifting through 13 years of data from NASA's Fermi telescope.

"It is a completely accidental discovery," Kashlinsky said in a statement. "We found a much stronger signal, and in a different part of the sky, than what we were looking for."

What makes this gamma-ray signal even stranger is the fact that it is located near another unexplained feature ...