Space is NOT black: NASA probe staring into cosmos' darkness discovers unexpected light

Once they had subtracted light from stars and camera quirks, the researchers were left with light arriving from beyond the galaxy.

The next step was to remove all light attributable to all known the galaxies, yet once that was accomplished, there was still plenty of unexplained light.

Dr Marc Postman, an astronomer with the Space Telescope Science Institute, said: “[Maybe there is] some other source of light that we don’t yet know what it is.”

Dr Michael Zemcov, a Rochester Institute of Technology astrophysicist, not involved with the research, added: “They’re saying that there’s as much light outside of galaxies as there is inside of galaxies, which is a pretty tough pill to swallow, frankly.