Scientists have searched for dark matter for decades. One thinks he may have caught a glimpse.

Few things in the universe are as puzzling as dark matter – the invisible, exotic “stuff” that apparently makes up most of the matter in galaxies.

The theory is this: to reconcile our current understanding of physics with what we observe in the cosmos, there must be enormous amounts of matter that we cannot see. Scientists are convinced that this “missing matter” exists because of the gravitational effects it exerts, but its direct detection has eluded scientists, who have had to indirectly infer how dark matter occupies the universe.

Nearly a century after dark matter was first theorized, a Japanese astrophysicist says he may have found the first direct evidence of its existence – gamma rays extending in a halo-like pattern – in a region near the center of our galaxy, the Milky Way.

“I’m so excited, of course!” Study author Tomonori Totani, a professor in the astronomy department at the University of Tokyo, told NBC News in an email. “Although the search began with the goal of detecting dark matter, I thought the chances of success were like winning the lottery.”

Totani’s claim to detect dark matter for the first time is an extraordinary claim that not all experts are convinced of. But the results, published Tuesday in the Journal of Cosmology and Astroparticle Physics, offer insight into the wild hunt for dark matter and the difficulties of searching the cosmos for something that can’t be seen.

Dark matter is estimated to make up about 27 percent of the universe, while ordinary matter — people, everyday objects, stars and planets, for example — only makes up about 5 percent, according to NASA. (The rest is made up of an equally mysterious component called dark energy.)

Totani’s study used observations from NASA’s Fermi Gamma-ray space telescope, aimed near the heart of the Milky Way. The telescope is designed to capture a type of intense electromagnetic radiation called gamma rays.

Dark matter was first proposed in the 1930s by Swiss astronomer Fritz Zwicky, who stumbled upon an anomaly while measuring the mass and motion of galaxies in the large Coma galaxy cluster. The galaxies were moving too quickly for his calculations, and instead of escaping from the cluster, they were somehow held together.

The resulting theories proposed a truly strange form of matter. Dark matter cannot be seen because it does not emit, absorb or reflect light. However, because it theoretically has mass and occupies physical space in the cosmos, its existence can be inferred based on its gravitational effects throughout the universe.

Different models exist to potentially explain dark matter, but scientists believe this mysterious matter is made up of exotic particles that behave differently from the ordinary matter we all know.

A popular school of thought suggests that dark matter is made up of hypothetical particles known as WIMPs (short for “weakly interacting massive particles”) that interact very little with ordinary matter. However, when two WIMPs collide, they could annihilate each other and release powerful gamma rays.

In his research, Totani, an astronomer and astrophysicist, discovered intense gamma ray emissions that he said were roughly equivalent to one millionth the brightness of the entire Milky Way. The gamma rays also appeared to spread in a halo-like structure across much of the sky. If the emissions were concentrated from a single source, this could suggest that a black hole, star or other cosmic object was the source of the gamma rays, rather than diffuse dark matter.

“To my knowledge, no phenomena from cosmic rays or stars exhibit a unique, spherically symmetric energy spectrum like that observed in this case,” Totani said.

But some scientists not involved in the study were skeptical of the results.

David Kaplan, a professor in the department of physics and astronomy at Johns Hopkins University, said it’s difficult to trace the emissions of dark matter particles with certainty because too much is still unknown about gamma rays.

“We don’t even know everything in the universe that can produce gamma rays,” Kaplan said, adding that these high-energy emissions could also be produced by rapidly rotating neutron stars or black holes that gobble up ordinary matter and spew violent jets of matter.

As such, even when unusual gamma-ray emissions are detected, it is often difficult to draw meaningful conclusions, according to Eric Charles, a researcher at Stanford University’s SLAC National Accelerator Laboratory.

“There are a lot of details we don’t understand,” he said, “and seeing a lot of gamma rays coming from a lot of the sky associated with the galaxy, it’s really difficult to interpret what’s going on there.”

Dillon Brout, an assistant professor in the astronomy and physics departments at Boston University, said the gamma-ray signals and halo-like structure described in the study are in a region of the sky “that is truly the most difficult to model.”

“Any claims should therefore be treated with great caution,” Brout told NBC News in an email. “And of course, extraordinary claims require extraordinary evidence. »

Kaplan called the study “interesting” and “worth following,” but said he was not completely convinced that follow-up analyzes would confirm the results. But he hopes that scientists will directly confirm the existence of dark matter in the future.

“It would be a total game changer, because it really is something that seems to dominate the universe,” he said. “This explains the formation of galaxies and therefore stars, planets and us, and is a key part of our understanding of the formation of the universe.”

Totani himself stated that further study was needed to prove or disprove his claims.

“If correct, the results would be too impactful, so community researchers will carefully examine their validity,” he said. “I am confident in my findings, but hope that other independent researchers will replicate these results.”

This article was originally published on NBCNews.com