posted by Anonymous on .
In Egypt, the Great Pyramids of Giza face slightly east of true north. Explain why the pyramids might not line up with true north as builders likely intended. Assume that the builders 4500 years ago could determine directions accurately.
I tried searching internet for this question, but didn't come up with anything. Does this have anything to do with the continental drift theory?
Check this site for an explanation.
The rotational axis of earth precesses
...The direction of true north is marked in the skies by the north celestial pole. For most practical purposes, this is the position of Polaris. However, due to the precession of the Earth's axis, true north rotates in an arc that takes approximately 25,000 years to complete. In 2102 Polaris will make its closest approach to the celestial north pole. 5,000 years ago, the closest star to the celestial north pole was Thuban
That is the magnetic pole Ms Sue.
The critical statement is this:
"....5,000 years ago, the closest star to the celestial north pole was Thuban ... "
Now of curse it should point close to Polaris
The pyrmaids might not line up with true north as builders likely intended because the north magnetic pole is geographically the south magnetic pole.
Oh Ok. I was getting confused before, thanks.