After proving the existence of Einstein's gravitational waves, researchers has once again discovered something that is not expected -- light bursting from the collision of two black holes.

Under normal circumstances, objects getting sucked at high speed in the black hole can radiate light, but scientists expect that materials, which are spinning around two black holes that are about to collapse into each other, will burn out before the merger.

However, that is not the case to GW150914, dubbed after the date researchers discovered gravitational waves in collision of two black holes about 29 and 36 times the size of our sun. Using NASA's Fermi Gamma-Ray Space Telescope, researchers are able to detect a weak pulse of high-energy light from short Gamma-Ray Burst (GRB) lasting only about a second.

The discovery of the short burst of gamma ray is not that remarkable, but the short burst happening a few seconds after the discovery of the gravitational waves and its close proximity to the area of the black hole merger made it appealing to the scientific community, Space reported.

There is only 0.2 percent chance that a random fluctuation of gamma ray would appear near the proximity of the black hole mergers, researchers said.

According to the press release of NASA, the discovery of the short gamma ray burst alongside the gravitational waves could help researchers better understand the inner workings of the universe.

"There is an incredible synergy between the two observations, with gamma rays revealing details about the source's energetics and local environment and gravitational waves providing a unique probe of the dynamics leading up to the event," said Lindy Blackburn, a post-doctoral fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and a member of the LIGO Scientific Collaboration.

So far, the researchers are carefully assessing the connection between the two new discoveries and are very cautious in forming up a conclusion just basing in a single burst.

"This is a tantalizing discovery with a low chance of being a false alarm, but before we can start rewriting the textbooks we'll need to see more bursts associated with gravitational waves from black hole mergers," said Valerie Connaughton, a GBM team member at the National Space, Science and Technology Center in Huntsville, Alabama.

Their findings is under review by The Astrophysical Journal.