(NewsNation) — As thousands enjoy the annual Roswell, New Mexico, UFO festival, one man who studied the phenomenon for years says it’s time to put modern science to work at the site of the purported 1947 UFO crash.

“There is science still to be done in Roswell,” said Nike Pope, a retired UFO expert for the British Ministry of Defense.

“The fact that we’re still talking about these 80 years, nearly, after the event shows the enduring power of this mystery,” Pope told “NewsNation Prime.”

About 50,000 are visiting Roswell this weekend to watch movies, attend concerts, watch a parade and listen to UFOlogists recount what’s been a very busy year.

It’s been nearly a year since whistleblower David Grusch stepped forward with claims the Defense Dept. has been operating a secret UFO retrieval program. Despite repeated denials, there is still skepticism that the agency is being fully transparent.

Pope reminds us that that whole thing started in Roswell, not with a media or citizen report.

“It was the U.S. military, themselves, who said ‘We have recovered a flying disc.’ They changed their story within 24 hours and said it was just a weather balloon,” he said.

Despite decades of denial, the military is still the source of the most credible sightings these days – especially from military pilots, backed up by the technology at their disposal.

“We simultaneously have radar data, forward-looking infra-red camera films of these taken from the jets, and sometimes satellite data. Although, of course, a lot of that is still classified,” Pope said.

Pope also notes the recent “crypto terrestrial hypothesis” published by researchers at Harvard that aliens might be already here, walking undetected among us.

He calls it “refreshing” that many scientists and academics came together to write a paper called “A case for scientific openness to a concealed earthly explanation for Unidentified Anomalous Phenomena.”

“This is more of a thought experiment than a ‘we found something.’ A few years ago, this would have been inconceivable. Now, it’s out in the open,” said Pope.

“This is total vindication for people who, for years, were languishing in the fringe, thinking this was all conspiracy theory. Now, we’re having hearings in Congress. Scientists and academics are daring to ask this ‘what if’ question.”

And, on the overall hunt for UFO answers, Pope puts it simply: “This is the greatest mystery of our time, and its’s about time we got it out in the open.”