A man is close to solving the four-decades-old mystery signal from deep space, believed by some to have come from aliens. And he needs your donation to make it happen.

American astronomer Antonio Paris, a professor from St. Petersburg College in Florida, is trying to find out the origins of Wow! signal, an explosive blast of radio waves recorded back in August 1977 by astronomer Jerry R. Ehman.

As he was monitoring data from the “Big Ear” radio telescope of Ohio State University, Ehman encountered a super strong radio signal that lasted 72 seconds, referring to the exceptional transmission as “Wow!” on a printout.

The signal — 30 times more powerful than the usual radiation emanating from the area — was never detected again despite several attempts. It started to be rumored as an alien broadcast.

Wow! signal caught the attention of Paris, formerly in military intelligence for a decade and as a defense department special agent for four years. With a natural savvy for investigative work, he had his own hunch on what really produced the signal.

“I had a description of what the suspects should look like. I found that there are several comets in the area that match that description,” he said in a Business Insider report.

Paris and his team need to have a radio telescope up by Jan. 25 next year to solve the mystery, thus deciding to crowdfund the campaign. The experiment has so far gathered over $17,000 on GoFundMe, calling for help to “solve one of the greatest mysteries of the Universe.”

But what does Paris think caused the Wow! signal?

The signal is believed to be produced by two comets emitting hydrogen while in transit in the star cluster M55 in the constellation Sagittarius.

As comets pass by our sun, UV light breaks up their ice and create a massive hydrogen gas cloud around them. The case now, according to Paris, is that the frequency of the Wow! signal matches a frequency that is naturally given off by hydrogen.

“The frequency for the ‘Wow’ signal fell close to the hydrogen line, and the hydrogen clouds of 266P/Christensen and P/2008 Y2 (Gibbs) were in the proximity of the right ascension and declination values of the ‘Wow’ signal,” he explains on the GoFundMe page.

No one really pored over this idea prior to Paris because no one knew about the existence of these comets when the Wow! signal was first picked up.

When comets pass in front of a telescope, they would generate a brief signal that could be a possible match for the Wow! signal. Since the two comets will transit the neighborhood of this extraordinary signal this January, Paris’ group is scrambling to build a radio telescope to test the hypothesis.

The proposal, however, has its share of critics. James Bauer of NASA’s Jet Propulsion Lab in California said that while cometary hydrogen can have quite a reach, the signal would not be strong enough.

“If comets were radio-bright at 21 centimeters, I would be puzzled as to why they aren’t observed more often at those wavelengths,” he tells New Scientist, adding it is “Science 101” to test the hypothesis before it is ruled out.