The Laser Interferometer Gravitational-Wave Observatory, or LIGO, made potentially one of the most groundbreaking discoveries of the last 100 years last week, and the scientific community is still abuzz trying to make sense of it.

According to a report from Discovery News, it even prompted legendary British physicist Stephen Hawking to congratulate the team that made the discovery, expressing his opinion that the discovery answers a question more than a century old.

“These results confirm several very important predictions of Einstein’s theory of general relativity,” Hawking said. “It confirms the existence of gravitational waves.”

Einstein predicted the existence of gravitational waves when he wrote his theory of relativity, but nobody has been able to physically detect them until now. The discovery has massive implications for our understanding of the universe, shining light on the mysterious “dark” matter that has puzzled researchers for decades.

Astronomers’ preferred method of examining the universe is by picking up on the electromagnetic spectrum, which includes visible light, x-rays, and infrared radiation. This only gives researchers a partial view of the picture, however, as objects that do not radiate in the electromagnetic spectrum are undetectable to even the most advanced equipment.

The recent discovery shines a light on a huge chunk of the universe that was previously impossible to study. LIGO’s dual observation posts in Louisiana and Washington state confirmed the existence of gravitational waves, and confirmed that they matched the theoretical models of a union of two black holes nearly 1.3 billion light-years away from Earth. Theories that colliding black holes would generate gravitational waves were first written in the 70’s, and it wasn’t until now that physical evidence confirming their existence was found.

“The discovery is the first detection of a black hole binary system and the first observation of black holes merging,” said Hawking. “The observed properties of this system is consistent with predictions about black holes that I made in 1970 here in Cambridge.”

Hawking’s second law of black hole mechanics is particularly relevant in the discovery. The law suggests that entropy, the amount of disorganization of information in the universe, cannot decrease over time within a black hole. This means that if two black holes ever merged with each other. The combined area is greater than the sum of the areas of the two original black holes. Hawking also stated that the gravitational wave signal recently discovered also aligns with the “no-hair theorem,” which says that a black hole can be described as a function of its spin, mass and charge.

“The discovery also presents a puzzle for astrophysicists,” said Hawking. “The mass of each of the black holes are larger than expected for those formed by the gravitational collapse of a star – so how did both of these black holes become so massive?”

While the discovery presents a growing list of mysteries, one thing is for sure – gravitational waves exist, and the continued study of these waves will yield further insight into how the universe evolves.