What is the Evidence?
Polar Shift Theory
A select group of people believe that the poles have shifted multiple times within the last 200,000 years. A man by the name of Charles Hapgood(1958), presented a theory that the Earth's poles have shifted over four times within the last 120,000 years. He believes that the Earth's north pole first shifted to an area in the Yukon in Canada. Then 84,000 years ago, the pole moved from the Yukon to the Greenland Sea. From 54,000 to 48,000 years ago, the pole shifted from the Greenland Sea to the middle of Hudson Bay. It stayed there for roughly 30,000 years and then migrated to where it is now currently about 12,000 years ago. He sites the failure to explain climate change, continental drift, the sudden melting of ice sheets, and Earths formations as evidence for his theory. We know from a little intuition and common knowledge that his "evidence" is not strong enough to properly support his claim. Science has common up with clear and definite answers backed with physical evidence to explain a majority of these "unknowns".
Ancient astronaut(AA) theorists believe that the polar shift directly correlates with their beliefs of ancient aliens. They believe that megalithic sites lay on regions where the equators once were in the past 100,000 years. There is a supposed strong connection between sites such as the Giza Pyramids and Easter Island to equators of the past. This is because it is easier for spaceships to land and take off at the equator because the speed at the surface of the equator apparently gives an added eastward push of 500 m/sec according to former NASA engineer, Maurice Chatelain. It also explains how we have found remains of ancient human life, in places that are now considered to be "unfit for humans".
There is evidence that there could be small changes in axial tilt within the time frame proposed, but it is believed by a majority of the scientific community that polar shifts happen over a much longer time span. There have been shifts in the poles in Earth's history, but they have occurred well over 800 million years ago. Between 790 and 810 million years ago there was a shift upwards of 55 degrees. Within the last 200 million years there has only been a total shift of around 30 degrees. Also, AA theorists are connecting information that has no reasons for being connected, other than for a few "theories". They are using things that have not been scientifically proven, such as the polar shift theory, and using it as evidence for their AA argument.
Pyramids and Other Megalithic Structures
Ancient astronaut theorists believe that pyramids and other megalithic structures from around the world are interconnected. They believe that the pyramids are too similar in structure and function to just be a coincidence. Ancient pyramids are spread through out the world from the Giza Pyramids in Egypt, to the pyramid temples of Central America. In the Bible as well as other religious documents, many of the pyramids are said to have been built by/for the "Gods". This is taken as a direct translation to AA theorists that they were built for/by Ancient Aliens. It is believed that these structures were built for the purposes of landmarks, landing sites, feeding sites, shelters, and ceremonial sites.
While this is what ancient astronaut theorists believe, historians and scientists concur that the pyramids were built in a much more conventional manner. According to Donald Redford, professor of Classics and ancient Mediterranean studies at Penn State, the pyramids in Egypt were built as tradition. The Egyptian sun God, Ra, was said to have created himself from a pyramid shaped earth mound before creating all of the other Gods. This gave great symbolism to the pyramidal shape, as it was thought to have represented the sun's rays. Redford explains that the task was a challenging one, but not an impossible one. He says it took upwards of 30,000 workers to complete the Great Pyramid at Giza. Apparently the pharaoh that would take the throne would begin construction of their pyramids as soon as they took over. Massive Dolerite(hard rock) tools were used to smash the granite in the quarries to be extracted. They were then pulled out of the quarry and onto the pyramid on lubricated ramp. The process is depicted in ancient Egyptian drawings at the construction site(shown below).
Nazca Lines
AA theorists believe that lines like the ones pictured to the right, were constructed by aliens. They believe that the only logical explanation for the precision of these sketches, were that they were made from the air using alien technology. The uses for these lines are argued within the AA community but William Saylor, ancient astronaut researcher, believes that these lines were used to connect important locations as almost a map for spaceships hovering above. He also comments that he believes that these lines could have been constructed from less advanced technology than we think. He believes that a simple water cannon could have been used to make them. Saylor notes that they could have been made by some sort of "free-hand" method but thinks it is far more likely that the images were made with some sort of computerized device. Some of the sketches, he believes, are too precise and accurate to have been done with a "free-hand" device.
Experts on the areas around the Nazca desert believe that these lines were constructed by the Nazca culture between the years of 450-600 AD. They were believed to have been made by removing the red stones in which cover the ground, revealing the gray ground underneath. Though their purpose is not certain, they seem to have been made for religious purposes.