Did aliens visit Earth in ancient times? It's possible. The late Carl Sagan once argued that there was a "statistical likelihood that Earth was visited by an advanced extraterrestrial civilization at least once during historical times."

Did aliens visit Earth in ancient times? It�s possible.

The late Carl Sagan once argued that there was a �statistical likelihood that Earth was visited by an advanced extraterrestrial civilization at least once during historical times.�

A statistical likelihood is one thing. Is there any reliable evidence that any such thing ever actually happened?

None whatsoever.

So why do 3 out of 4 Americans believe there are signs that aliens have visited Earth in the past? I think there are two reasons. First and most fundamentally, when most people see a wonder of the ancient world, such as the Egyptian pyramids, they can�t imagine how our so-called primitive ancestors possibly could have built it.

Second, there are charlatans out there willing to take advantage of that lack of imagination by making exuberant claims that various cultural achievements in antiquity could have been accomplished only with the help of friendly aliens.

In the current issue of Skeptic magazine, documentary filmmaker Chris White shoots down a few of the most popular claims of past alien intervention.

For example, ancient alien enthusiasts find it unbelievable that Egyptians could have carved the huge stone blocks used to build the pyramids, especially since they didn�t have iron tools. Yet there is abundant archaeological evidence that shows teams of stonemasons used simple hammer stones to shape the blocks.

But fans of ancient aliens say that even if Egyptians somehow shaped the enormous blocks of stone, no mere humans could have moved them into place.

The truth, however, is indeed out there.

White explains that there are many ancient carvings that show �Egyptians using wooden sleds to move � blocks the size and shape of the ones used for the pyramids.� It is amazing what our ancestors could achieve with creativity, determination and a large workforce.

Believers in ancient aliens frequently point to an engraved stone slab from a Mayan tomb, which they claim depicts an astronaut at the controls of a spacecraft.

If you take the time to study the symbolism of the Mayan religion, however, it is clear that the �spacecraft� actually is the primordial world tree with a celestial bird perched in its upper branches. And the barefoot �astronaut� really is the deceased Mayan king descending into the underworld.

These examples are typical of what is offered as evidence of ancient aliens. The purveyors of this nonsense assume our ancestors were ignoramuses. If they accomplished some great thing, then aliens must have helped them.

Champions of ancient astronauts look through volumes of prehistoric art and cherry-pick images that bear � at best � only a superficial resemblance to something that could be construed as alien technology.

They give no thought to what those images represented in their original cultural contexts. Using this method, an Egyptian carving of a lotus flower can be reinterpreted as an electric light bulb, and a South American sculpture of a sucker-mouth catfish can be imagined to be a delta-wing fighter jet.

Archaeologists don�t take these views seriously, but by ignoring them, we allow 3 out of 4 Americans to buy into a fantasy.

Bradley T. Lepper is curator of archaeology at the Ohio Historical Society.

blepper@ohiohistory.org