by Chris Peterson » Sun Sep 07, 2008 8:36 pm
apodman wrote:Hey, I only said strange ... not offended, nor outraged, nor feeling the need to replace any terminology.
I didn't take it wrong, but was serious if you had an alternate terminology in mind. The 2D coordinate system we find generally convenient to describe our position on the surface of a sphere does go to hell at the poles. Reminds me of that old puzzle about walking a mile south, a mile east, and a mile north, bringing you back to your starting point... what color is the bear you see?
As an astronomer, I see the same thing happen in the sky. If I've got my scope pointed near a pole, I can spin one axis through 360° and see hardly any change in where I'm pointing. Similarly, I can just jog the scope a few arcminutes and have one of the coordinates jump all over the place. Whether you are a navigator on the Earth, near the poles with an equatorial telescope, or near the zenith with an altaz telescope, there are points which are singularities with a 2D coordinate system mapping a non-Euclidian plane.
[quote="apodman"]Hey, I only said [i]strange[/i] ... not offended, nor outraged, nor feeling the need to replace any terminology.[/quote]
I didn't take it wrong, but was serious if you had an alternate terminology in mind. The 2D coordinate system we find generally convenient to describe our position on the surface of a sphere does go to hell at the poles. Reminds me of that old puzzle about walking a mile south, a mile east, and a mile north, bringing you back to your starting point... what color is the bear you see?
As an astronomer, I see the same thing happen in the sky. If I've got my scope pointed near a pole, I can spin one axis through 360° and see hardly any change in where I'm pointing. Similarly, I can just jog the scope a few arcminutes and have one of the coordinates jump all over the place. Whether you are a navigator on the Earth, near the poles with an equatorial telescope, or near the zenith with an altaz telescope, there are points which are singularities with a 2D coordinate system mapping a non-Euclidian plane.