Some time ago, I had the misfortune of watching a History Channel "investigation" of the so-called "Ancient Astronaut" theory. Basically, the "theory" (really more of an untestable hypothesis) puts forward the idea that all of the great monuments and inventions of history, such as Stonehenge, the pyramids, the statues of Easter Island, etc., etc., are not, in fact human inventions, but rather alien built (or at least alien instructed). It's a theory that became wildly popular in the late 60's and 70's after Erich von Däniken's ridiculous book "Chariots of the Gods?"
It is one of the dumbest ideas in the history of mankind, and I was infuriated that the History Channel gave it as much serious airtime as they did.
Proponents of the "theory," suggest that the "proof" lies in the following:
1) Some ancient artwork from around the world looks like aliens or astronauts by today's standards.
2) We're more "advanced" than those ancient cultures were, so if we don't know exactly how to make their monuments and technology today, then obviously, no one could have done it back then.
Argument #1 is remarkably like an old joke I remember: A man goes to see a psychiatrist. In order to diagnose the man, the psychiatrist shows him a series of inkblots, and asks him to say what he thinks of each time. When he looks at the first inkblot, the man says "sex." The psychiatrist shows him the second inkblot. Again, the man says "sex." The third, fourth, and fifth inkblots are all the same - "sex," "sex," and "sex." Finally, the psychiatrist says "I understand your problem - you are obsessed with sex!" The man says, "What, me? You're the one with all the dirty pictures!"
It is not a rational argument to say that because a picture might look like an alien or astronaut to modern man, it somehow follows that it must be such a thing. A great example of this is found here at Wikipedia.
According to von Däniken and company, the drawing from the sarcophagus lid of the tomb of the Mayan ruler Paca "clearly" shows him sitting in some sort of rocket with flames coming out of the bottom.
Sorry, but if aliens were able to travel vast interstellar distances, they most certainly didn't do it in ANYTHING that looks remotely like a 1969 moonshot rocket. Such technology would not include burning chemical fuel shooting out of the bottom (if, indeed, those are supposed to be flames).
Where does this art interpretation end? I could look at Salvador Dali's The Persistence of Memory and decide that Dali "obviously" understood that time and space are warped together - perhaps with many more dimensions curled and twisted. Yes! "Obviously" Salvador Dali understood string theory - long before there was such a thing. "Clearly," the only way that is possible is if he was an alien - or, maybe had alien tutors.
Let's look at argument #2. If modern man can't do something, then ancients couldn't have done it, either.
The Pyramids at Giza were built out of stone. The Luxor in Vegas is made out of steel, glass, and concrete. I doubt the workers who constructed the Luxor would have a clue how to make a pyramid out of stone. By the same token, I'd bet anyone who cares to take me up on it a million dollars that the skilled craftsmen who made the Great Pyramid wouldn't have a clue how to make the Luxor - or they would have done it, because it was a hell of a lot easier, and those giant lights out of the top are just amazing.
But those workers thousands of years ago didn't know how to make a massive hotel with running water, electricity, and hi-tech casinos inside, precisely because there weren't any advanced warp-speed-having alien beings giving them the inside scoop.
What they did have were skilled workers who knew how to work with the primative things they had. From the time those stonemasons were old enough to hold a chisel, they had a job. The didn't go to school, hang out at malls, or text each other on iPhones; they carved stone in stright lines. If they didn't do it right, someone hit them with sticks and whips and made them do it again. By the time they were old enough to work on something as important as the Great Pyramid, they could chisel a stone in a line as straight as a razor's edge in their sleep.
If aliens were helping the ancient Egyptians, the Great Pyramid should have been made out of diamond, with hot and cold running water and zero-point energy extraction generators. And really cool laser lights coming out of the top....
Another find which sent the "Ancient Astronaut" guys into a tizzy was the "Antikythera Mechanism," an actual ancient computer that could calculate the phases of the moon, lunar eclipses, and all sorts of cool stuff. There is a fantastic site about it here.
"Obviously," aliens must have helped the ancient Greeks make this - right? On what possible basis could anyone form such a ridiculous conclusion? There's not one scrap of advanced technology in it. No microchips or transistors - just clockwork gears which were well-known at the time; Brilliantly designed clockwork gears, clearly made by a genius - but clearly, a HUMAN genius.
Human beings - the most brilliant things ever to step foot on planet Earth - invent marvellous solutions to problems using whatever is available at the time. When new materials and technology become available, we - as a race - forget the old methods. It's just evolution applied to technology.
We forget how to do things we don't need to do anymore. The pyramids, for all their coolness, are just basically big piles of rocks.
Quick test for this one which you can try on the weekend: Go out into the wilderness, track a wooly mammoth, kill it, butcher it for meat, and use it to make your clothing, bowstrings, etc.
What?!? There aren't any wooly mammoths in your part of town? You don't know how to kill a giant beast, skin it, butcher it, and use its parts for clothing and supplies? Well, "obviously" primitive man couldn't, then. And if they did, say, hunt wooly mammoth to extinction, then "obviously" aliens must have shown them how.
My dad could take apart a carburetor and put it back together with his eyes closed. I barely understand how the things work, because the first car I ever bought had electronic fuel injection. My grandchildren won't have a clue what a carburetor even looks like, and their grandchildren will have forgotten the word. Their grandchildren, should they find one, will be utterly stunned that primative people who didn't have fusion power and anti-grav hover vehicles could ever have invented such a thing. Therefore, applying the "Ancient Astronaut" line of reasoning, "obviously," my father was an alien, and I am therefore half-alien.
Or maybe, the reasoning is faulty, and the whole "theory" is just a lot of wishful thinking. In ancient times, people attributed everything they couldn't understand to ghosts and spirits. Today, we've replaced ghosts and spirits with aliens and UFOs.
The saddest part of that is that it minimizes the brilliance of this amazing species known as homo sapiens. The human mind is the most amazing evolutionary adaption this planet has generated. To belittle that stunning bit of gray matter between our ears by saying we needed some spacemen to come tell us how to carve stones is not only sad, it's positively insulting...