¶ Spherical Triangle Sequence
← Spherical Triangle Sequence | Spherical Triangle Sequence →
Index Entry
"distance and going through the atmosphere there’s always a spin that’s brought about by rotation. There is as a result pressure drafts on one side, and there’s air in motion-- wind-- and all your traceries are always going to be corkscrew. But they are the most economical relationships and they are geodesics.
"So geodesics are curved lines. And I’ve given you the most prominent geodesics like the great circles, the most economical relationships between events on the surface of our Earth. Now, understanding that, you will understand that our spherical trigonometry is always done with great circles. You were brought up with your plane geometry where a straight line is the shortest distance between two points. Now I gave you earlier today the non-straight line. . . .
“Here then is our Earth. I’m going to the north pole and I’m going to take a meridian which is a great circle and it’s going to impinge on the equator at 90 degrees. So this meridian comes and impinges on it and here’s the center of our Earth. It would go like that. And now, having impinged on the equator at 90 degrees, I’m going to leave the meridian and”
