Why assuming? There is evidence but not conclusive evidence that aliens did it - it's possible that man knew more that we think he did and that ancient technology was somehow lost. Barring that, we're looking at alien influence.
So you haven't taken physics in college? You'd rather believe in aliens than in God? I mean, sure the possibility of aliens existing is higher than God, but again no evidence.
the consensus is that we still don't know how they were built, there are some theories but nothing definitive.
There are some disagreements on the exact techniques, but no one would doubt that man built them. Except of course people like you. I'm not saying aliens didn't help, but in the absence of evidence we once again come to a road block.
http://en.wikipedia....tion_techniquesyou really have no clue then, you can't describe the motion of the star sirius with the naked eye or even very powerful telescopes, it wasn't until relatively recently that we've had the technology to do this.
I thought we were taking about the solar system, not stars?
The dogons, sumerians, and mayans all had knowledge that couldn't be obtained without advanced technology.
Again the evidence is inconclusive, otherwise why isn't it in the history books? Point is, most of this theory is speculation based on a few ancient artifacts and writings.
There's more evidence to support Genesis (biblical creationism) than this.
Almost all ancient civilizations tell of reptilian-like aliens who seeded mankind, are you aware of this?
Just a few civilizations take about it, not all. And those that do, talk about symbolism to snakes or lizards which was a common thing to do back than.
what about telling the color of planets, describing the motion of the solar system, that mars has water under the surface, etc...
The color and motion of the major planets can (on a clear night) be seen by the naked eye. That mars had water (though I have never heard of this) is either made up or could have been an ancient story about a place were God's were from.