2006-08-25 01:31:28 · 8 answers · asked by ? 3 in Science & Mathematics ➔ Astronomy & Space
Gamma Cephei will become the North Pole Star instead of Polaris as soon as 4000 AD and be itself replaced by another star from Cepheus within a further 2,000 years, so whilst significant movement does not occur within the lifetime of one individual, within the lifetime of a civilisation that keeps and archives records, it is a different matter,
A constellation of stars just happen to be in our line of sight in a sector of the heavens, for a while, they are not physically related in the sense of being at a similar distance away from us as each other or sharing the same proper motion as one another, An exception is the star cluster The Pleiades which are a distinct group of 500 stars, 12 light years across, in motion together but even they, over time, will break apart from one another.
The sun has a circular orbit within the Milky Way of about 250,000 years, travelling a distance of 1 light year in 1400 Earth Years or 1 AU in 8 days, so our observation point is on the move, too, It has made something like 20-25 such orbits whilst mankind had been on the planet.
By about 11,000 AD Barnard's Star, current;y 5.96 light years away will have moved to within 3.8 light years from us and have become the nearest star to us (it is currently the 4th nearest) so the idea of a fixed firmament is a bit of a Ptolemaic hangover, I am afraid.
2006-08-25 02:23:53 · answer #1 · answered by Anonymous · 6⤊ 0⤋
The universe is not rotating. Earth rotates on its axis, it revolves around the Sun, the Sun revolves around the center of the Milky Way galaxy, but the universe itself is not rotating.
However, the stars do move and the constellations do change, but since the stars are so far away that it takes many thousands of years for them to move far enough to change the constellations noticeably.
2006-08-25 09:33:52 · answer #2 · answered by campbelp2002 7 · 0⤊ 0⤋
stars in a constellaton with respect to one another are fixed but the constellation on the whole moves along with moving universe.
2006-08-25 08:40:21 · answer #3 · answered by littleoli1992 2 · 0⤊ 0⤋
Actually they are in movement. The light that is reaching Earth from those stars left millions of years ago. 25,000 years ago, the constellations we know didn't even exist. 25,000 years from now, Vega will be the North Star instead of Polaris. The stars have moved, but the light has yet to reach us. It will be gradual, so don't expect our descendants to look up and suddenly see the Big Dipper out of alignment
2006-08-25 09:00:46 · answer #4 · answered by James U 2 · 0⤊ 0⤋
no the constellations are not fixed but they seem to becoz we along with them are moving.
2006-08-26 11:48:49 · answer #5 · answered by jignesh 1 · 0⤊ 0⤋
well who told u that the univers is rotating it expands and we dont see the movement cause we are moving with them too
from well-wisher
Avik
2006-08-25 09:10:19 · answer #6 · answered by Anonymous · 0⤊ 0⤋
They seem to be fixed because we are moving with them at the same speed.
2006-08-25 08:35:08 · answer #7 · answered by Saber 1 · 0⤊ 1⤋
This is based on the concept of relative motion.
2006-08-26 03:23:59 · answer #8 · answered by Anonymous · 0⤊ 0⤋