ORLANDO, Fla. — He appeared as if a hologram at first — then solid — suddenly there and clear at the edge of the forest behind Trish Bishop's home in Kissimmee in 2013.

When he turned around, it was his face, she remembers, that stopped her. Bulging eyes. Skin white as chalk. And massive jaw.

"I've got a freaking alien in my backyard," she thought.

And then he was gone.

It would be four years before she told her story, before she'd discover the Mutual Unidentified Flying Objects Network, a nationwide organization 50 years old, and file her report under case number 84886.

But she worried: Who would believe her? These days, more people than you'd think.

Across U.S. restaurants and meeting rooms, MUFON groups gather every month with the enthusiasm that once gripped the nation during the Cold War. The Space Coast group, made up of some former NASA employees and engineers, has 118 members. Across the nation, they number 3,500, with additional offices in 42 countries.

For many years, they were alone entertaining UFO theories. No more.

In the past two years, scientists, politicians and professionals have increasingly been willing to touch the taboo subject and perhaps lend a little credence to believers.

In December 2017, the New York Times uncovered that the U.S. had funded a secret, $22 million, five-year project to study UFO claims.

What's changed, said Robert Powell, an executive board member on the nonprofit Scientific Coalition for Ufology, is our understanding of the universe. As scientists have discovered more Earthlike exoplanets and begun to delve into the options for interstellar travel, the conversation has been shifting.

"We still think of ourselves, as a species, as the center of everything," Powell said. "Once you at least start to discuss interstellar travel, you have to admit that, if there is intelligent life out there, then they have to be able to travel interstellar, too."

The challenge with alien sightings has always been the lack of evidence. Psychologists say common explanations include a person projecting their unconscious desires onto something, or a predisposition to believe in conspiracy theories, said Alvin Wang, a psychology professor at the University of Central Florida. People who believe they witnessed something may seek out others who reaffirm that belief, like "being in an echo chamber," he said.

In 1961, Kathleen Marden was 13 when she got the call: Her aunt and uncle — Betty and Barney Hill — said they'd seen a UFO in the White Mountains in New Hampshire. Betty's dress was torn and Barney's shoes were scuffed. There were two hours they couldn't account for and Barney Hill was sure he'd seen eight to 11 figures that were "somehow not human," Marden said.

It wasn't until the Hills were put through a hypnosis session by Boston psychiatrist Dr. Benjamin Simon that their story was revealed.

The Hills' alleged UFO abduction was made public in 1965 — and the story gripped the nation. "Did They Seize Couple?" the Boston Traveler posited. "I Was Quizzed in 'Space Ship,' " another headline said.

Marden has dedicated her life to uncovering the truth behind what she says was government tampering with the Hills' case.

"I absolutely do think that there is a shift, that people are giving more credence to this," she said, pointing to the Pentagon's Advanced Aerospace Threat Identification Program, revealed by the New York Times, as the turning point.

The program was run by military intelligence official Luis Elizondo in partnership with Bigelow Aerospace to study cases of U.S. military personnel observing unknown objects.

One case in particular garnered attention when it was declassified because videos showed a craft with no apparent propulsion moving at fast speeds. It was filmed in 2004 by two Navy F/A-18F fighter jets off San Diego. Navy pilot Commander David Fravor said in late 2017 that it was "something not from Earth."

Historically, NASA has not weighed in on the issue much. But scientist Silvano Colombano of NASA Ames Research Center argued in a March 2018 white paper that the scientific community should be more open to "consider the UFO phenomenon worthy of study" and engage in "speculative physics" grounded in solid scientific theories but with some "willingness to stretch possibilities as to the nature of space-time and energy."