Egyptians to the Ancient Sumerians to the Ancient Babylonians to the Mayans simply collectively decided to expend ENORMOUS amounts of "blood and treasure" to build observatories, so they could "star watch" all night and constructed calendars that measured time constructs that extended over tens of thousands of lifetimes Sounds even more ridiculous than even the most outrageous explanations of "extra-terrestrials."
Depending upon which "New Age expert" you consult, SOMETHING "civilization changing" WILL occur either on Dec 21, 2012 or within the following 7 to 8 years. That could be anything from a pole reversal, to mega-earthquakes to mega-tsunamis to cometary showers, to solar flares to world-wide thermonuclear war and mass extinction.
As far as "extra-terrestrials," are you aware that ancient civilizations and religions, including Christianity described alien visitation? That gnostic Christianity describes the Archons as Reptiles and small grey humanoids with enlarged heads? Are you aware of the recently declassified evidence of NAZI flying saucer technology, based on allegedly "channel" ET technology from a Nordic alien race, believed by the NAZIs as being the Aryans? How are the machined spheres discovered in rock strata carbon dated at 2.8 BILLION years. These spheres look EXACTLY like Iapetus, Saturn's largest moon; which, by the way, looks remarkably like the "Star Wars" "Death Star". Perhaps, most interestingly, these "man-made" spheres resemble Iapetus as it looks NOW; NOT as it would have looked if it is, as Richard Hoagland conjectures, when it was a "brand spanking new" ARTIFICIAL satellite and looked ALMOST EXACTLY like the "Death Star."
Do you think all "crop circles," many involving high=level math are created by "drunk Welshmen"? How about the "river turning to 'blood' in China recently? What kind of algae has NO DNA?
Laugh all you want, right up until the SHTF.