What length of time is required for the Big Dipper to change from one position to the other?

Answer 1

From the point of view of an observer on earth, the stars are always moving.

The question is: How long does it take you to notice a change in position ?

If you line up a star with a tree or a house, you ought to be able to notice it

within 5 minutes.

Answer 2

The Big Dipper is made up of the seven brightest stars of the constellation known as Ursa Major. They are not the same distance from earth. The farthest of the seven is also the brightest, Dubhe, or alpha UMa. It is 124 light years from earth, so the light we see has been on its way for 124 years. The closest of the seven is Megrez, delta UMa at 58 light years. So light from that star has been on its way for 58 years. The others are somewhere between these two in distance. We group them together only because of the way that they incidentally appear to us in the sky, and we do this for convenience and quick navigating of the objects in the sky. From the point of view of the stars themselves, there is no particular reason to group these stars together.

Answer 3

The Big Dipper is not a thing; it is a coincidental pattern of dots in the night sky, and people "see" the pattern of a dipper.

Each of the stars that make up the Big Dipper has its own proper motion. While the stars all move, they are so far away that the movement is not noticeable over the lifetime of a person, or even of a civilization. 10,000 years ago, the Big Dipper would have looked somewhat different than it does; 10,000 years from now, it will look different too. Of course, we won't be alive in 10K years.

Answer 4

The Big Dipper does not rotate. The Big Dipper, like other constellations in the skies, is merely an arrangement of stars. While the stars do move, they are so far away that even a lifetime of observation would not let you notice any difference.

And constellations do not really exist, except in the minds of the observers. There is no giant ladle in the heavens; just a grouping of individual points of light, each of which is a sun with its own planets and companions. It is our minds playing tricks with us, that causes us to see patterns where there are none.

The Earth, however, does rotate, taking 24 hours to complete one rotation. Because we think of ourselves as standing still, the actual motion of the Earth is translated into an APPARENT motion of the skies.