In a time filled with UFO conspiracy theories, a former NASA official is pushing back against claims of alien visits to Earth. Joseph Gutheinz, a retired NASA investigator and current attorney, says science—not speculation—should guide the discussion.

“Prove it. Honestly, prove it,” he challenges UFO believers. “They’ve been claiming that there have been UFOs since the 1940s. And, you know, Area 51 supposedly houses UFOs. Have someone go in, look at Area 51.”

During his NASA career, Gutheinz often heard wild claims. “I would regularly get calls from individuals who believed they were abducted or had a chip in their brain from aliens,” he said.

His response? “The possibility of anybody coming from another world to visit us was beyond unlikely… See a psychiatrist.”

He points to the vast distances in space as proof. “There are up to 400 billion stars in the Milky Way… but the closest solar system is Alpha Centauri, 4.4 light years away—25 trillion miles. If somebody started flying to Proxima Centauri, it would take them over 70,000 years. Nobody is visiting us from another world, likely.”

If life exists nearby, he says, it’s not intelligent. Moons like Europa or Titan might host microbes, but “it’s nothing that’s going to visit us in a flying saucer.”

So what explains UFO sightings? Gutheinz suggests earthly origins. “If you’re seeing something up there, and it’s real, it’s coming from the Chinese or the Russians or your next-door neighbor flying around with their drone.” He believes military secrecy fueled UFO myths.

“In the 1940s, when UFO stories started, the military was probably testing aircraft and didn’t want Russia to know,” he said.

“If the UFO cover worked, I wouldn’t be surprised if some in government played along to hide stealth technology. The bottom line is, we use the UFO cover to hide a lot of things.”