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True north meaning the fixed point we call the north pole. It doesn't change because it's geographic; nothing to do with the pole star.
by zarmin 7y ago
True north meaning the fixed point we call the north pole. It doesn't change because it's geographic; nothing to do with the pole star.
- pavlov 7y agoThanks, I was getting norths mixed up. Although I’m still confused on this: how would the Egyptians know to align a building with this specific point on a sphere before the geographic convention existed, and both magnetic North and astronomic markers were in different positions?
- zarmin 7y agoAnother good question is: _why_ would they go out of their way to align these megaliths so precisely?
- tialaramex 7y agoTrue North is the point the axis of rotation passes through. So, assuming you're aware that you're stood on a sphere (which basically anybody who'd thought about it hard enough or had conquered enough of the planet to do experiments knew since antiquity) and that the sphere is spinning then you know in some sense which way North is by watching the stars apparently gracefully moving in the night sky. If you're lucky, as the stars move one of them stays still or almost still, it points North (or, in the other hemisphere you've got one pointing South). Today Polaris fills that role and we call it the "North Star".