by Chris Peterson » Fri Feb 01, 2008 8:17 pm
zbvhs wrote:Consensus of opinion in the car was that we were seeing sunlight coming over the Pole reflected upward by the polar icecap. Could be we had one of those rare nights when skies were clear all the way north to the pole.
Quite impossible. Because of the curvature of the Earth, about the farthest you can see atmosphere is 700 miles. That is, at 700 miles, you are seeing the very top of the atmosphere on the horizon. You were what, something like 3000 miles south of the North Pole?
Realistically, from the surface of the Earth, you are basically living in the center of a shallow cylinder several hundred miles in radius. You can't see any atmospheric phenomena outside that cylinder- clouds, meteors, aurora, etc.
Auroral activity is only one possibility. If the rays you saw were above the solar point, you may have seen the
Zodiacal light (possibly fragmented by otherwise invisible clouds). Depending on how far north you were, you may even have been seeing twilight (again, possibly fragmented by clouds- essentially, twilight
crepuscular rays). From Bismarck, on July 1 at 2 AM, the Sun is directly north and only 20° below the horizon- just about the beginning of astronomical twilight.
[quote="zbvhs"]Consensus of opinion in the car was that we were seeing sunlight coming over the Pole reflected upward by the polar icecap. Could be we had one of those rare nights when skies were clear all the way north to the pole.[/quote]
Quite impossible. Because of the curvature of the Earth, about the farthest you can see atmosphere is 700 miles. That is, at 700 miles, you are seeing the very top of the atmosphere on the horizon. You were what, something like 3000 miles south of the North Pole?
Realistically, from the surface of the Earth, you are basically living in the center of a shallow cylinder several hundred miles in radius. You can't see any atmospheric phenomena outside that cylinder- clouds, meteors, aurora, etc.
Auroral activity is only one possibility. If the rays you saw were above the solar point, you may have seen the [url=http://www.cloudbait.com/gallery/gallery_meteor.html]Zodiacal light[/url] (possibly fragmented by otherwise invisible clouds). Depending on how far north you were, you may even have been seeing twilight (again, possibly fragmented by clouds- essentially, twilight [url=http://www.cloudbait.com/gallery/gallery_sky.html]crepuscular rays[/url]). From Bismarck, on July 1 at 2 AM, the Sun is directly north and only 20° below the horizon- just about the beginning of astronomical twilight.