Definition: [n] the apparent surface of the imaginary sphere on which celestial bodies appear to be projected Synonyms: celestial sphere, empyrean, firmament, heavens, sphere, welkin See Also: apex, apex of the sun's way, celestial point, nadir, solar apex, surface, zenith, zodiac
Imagine the sky as a great, hollow, sphere surrounding the Earth. The stars are attached to this sphere---some bigger and brighter than others---which rotates around the stationary Earth roughly every 24 hours. Alternatively, you can imagine the stars as holes in the sphere and the light from the heavens beyond the sphere shines through those holes. This imaginary sphere is called the celestial sphere, and has a very large radius so that no part of the Earth is significantly closer to any given star than any other part. Therefore, the sky always looks like a great sphere centered on your position. The celestial sphere (and, therefore, the stars) appears to move westward---stars rise in the east and set in the west.
Even though it is now known that this ancient model of a stationary Earth is incorrect, you can still use this model because it is a convenient way to predict the motions of the stars and planets relative to a location on the Earth. A star's apparent brightness is actually determined by its distance, as well as, its physical size and temperature. It is also now known that the stars apparent motion around us is due to the Earth rotating once every 24 hours on its axis. The stars are stationary and the Earth rotates from west to east. This rotational motion makes the stars appear to move from east to west around us. The celestial sphere model is used by planetaria to simulate the night sky.
ronski wrote: If it's crap, it's at least elegant crap.
Hmm, maybe this theme does have legs....
I too am seeking some inspiration...
robotland wrote:...what's this "ticket flyer" business? Are you on the mailing list for the firstestcheapest tix after you've gone once, or something? I want mail. I never get mail. poop. It's not fair. (lower lip fully extended.)
Iago wrote:Oh Boy, Oh Boy, Oh Boy!! Does this mean Alien Abduction Camp will be back again??? Please, please, please........!
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