Scientist explains how UFOs have been visiting Earth 'since Roman times'

A UFO expert has explained how aliens could have been visiting Earth "since Roman times".

Physics professor Kevin Knuth has devoted much of his time to investigating whether reports of UAPs (unidentified anomalous phenomena) could be linked to extra-terrestrial life and he's convinced aliens could have discovered the Earth millions of years ago and been visiting every since.

In a piece written for Popular Mechanics, Knuth explained the likelihood of an alien species discovering out planet is small but if it they have then it happened a very long time ago. He expained: "I was able to estimate that the probability of an interstellar-capable civilization visiting Earth is about 0.000405 per cent.

"That means that out of all of the spacefaring civilizations in the galaxy, only about 0.00009 percent of them will physically encounter our planet. Not only is interstellar travel difficult, but Earth is hard to find.

"My simulations also suggest that if there are extraterrestrials present on Earth today, then they probably found Earth a very long time ago- more than 1.7 million years ago (on average about 1.2 million years ago). This makes sense, given that UFOs have been observed by humans since Roman times."

Knuth also revealed he thinks any alien species that has discovered Earth must be "close by" - pointing to examples of UFOs being present at times of nuclear disasters.

He added: "Another powerful piece of evidence that we aren’t alone is that UAP sightings tend to occur the day following a nuclear disaster. It happened after Fukushima; it happened after Chernobyl.

"Whether aliens are monitoring our technical progress, helping us prevent existential disaster, or simply gawking like humans beneath the Aurora Borealis, they must be close by - on Earth or at least in our solar system - to get here so quickly.

"Carl Sagan once dismissed UFO sightings by arguing that there were simply too many of them, that interstellar spacecraft wouldn’t be “arriving every other Tuesday.” He was absolutely right. They appear to show up so often because they’re already here."

Knuth added of his research: "Fortunately, UAP research is taken much more seriously than it was when I was in graduate school. When I first started researching and writing about UAPs, I fretted a lot. I thought I was going to get myself into hot water.

"But I have been pleasantly surprised by and grateful for the positive feedback I’ve gotten ...

"I think there’s a growing sense that we should, at the very least, know what—and who—is flying in our skies. If it turns out not to be an alien spacecraft, that’s fine, but we’d all be safer if we figured it out."