Has anyone suggested aliens as the culprits yet? Well yes of course they have. If the current state of human knowledge doesn’t quite explain something, aliens will be summoned every time. No doubt.
As an explanation, the alien theory completely sucks, it doesn’t help in any way at all. Even if you are happy to believe that aliens came down here ages ago and made patterns on the earth (which I’m not), you’re still left with the question of why they did it. So you’re no closer to an answer.
As with most mysteries of archaeology, some bright spark will come up with a plausible explanation one day and we’ll all go “aaahhh… that makes sense” in unison and then wander off to stare at something else.
Here’s my theory for the record: an ancient tribe of Peruvians worshipped a god who absolutely loved indentations in the ground, so they made loads of them to please him. If there was ever sickness, drought or starvation in their village they would go out and dig some more holes to try to appease him. There you go.
☛ More Mystery: The Somerton Man — A Properly Weird Aussie Murder Mystery