Why do stars in constellations not move?

Answer 1

Actually, the stars are moving, as is everything else in the universe. It's just that the distances are so vast from our perspective (viewing point) that any movement is virtually undetectable.

Answer 2

I don't think so. A constellation is defined as the region between certain coordinates in the sky (declination and right ascension - equivalent to latitude and longitude on Earth). These coordinates move, in the sense that the entire reference system moves compared to the background stars, due to the precession of Earth's axis. However, I read that the coordinates for the year 1875 are used; it seems they have not been adjusted.

Answer 3

All of the stars move; every one has its own "proper motion". However, the proper motion of even the fastest and closest star isn't enough to be noticeable over several human lifetimes.

Perhaps you are referring to a star that does not APPEAR TO move? One star, Polaris, is so nearly directly above the north pole of the Earth that it seems to stay in one spot in the sky, while all the other stars appear to wheel around it. But if you point your camera at Polaris and take a long time-exposure, you will see that even Polaris "moves"; it isn't EXACTLY above the north pole, and appears to make very tiny circles in the night sky.

In fact, Polaris is about 0.6 degrees away from being exactly above the north pole.

Answer 4

Most of the stars in the night sky that can be seen with the naked eye are in fact not moving very much relative to us and to other stars in the Milky Way. The stars we see are within the Milky Way itself. The galaxy is turning relative to other galaxies, but we are turning along with the other objects in the galaxy. There may be a small amount of movement of those visible stars but it is not enough to be noticeable to us earth-bound observers.

The movement that you hear and learn about, the movement of galaxies away from us at great speeds, involve galaxies and not individual observable stars. And there are very few galaxies that are at all visible from earth.

You may be using the term 'star' the way it was used in ancient times, thinking of planets as moving stars, and the distant stars as 'fixed'.

______________________________

While all of the stars - and the Sun itself, for that matter - are moving fairly rapidly through the galaxy, you would need to live a dozen lifetimes or more to actually notice any movement. The stars are too far away! When we talk about "apparent movement", we are generally talking about the rotation of the Earth. With us standing on the Earth like a child riding a carousel, we see the stars all moving along together - when it is US doing the moving.

From that perspective, the only "unmoving star" is the north pole star, Polaris. It appears to be fixed in the sky, because of the useful - but ENTIRELY coincidental! - alignment of the Earth's axis of rotation and the star.

Answer 5

no stars move.its the earth spinning that makes it look like they more. the north star is directly abouve us so it doenst appear to move.

Answer 6

Because Earth is travelling through space at great speeds.

Answer 7

because its almost directly in-line with the north pole

it is situated in the direction of earth's axis

Answer 8

They don't. It is Earth that rotates; as a result, stars (and groups of stars) seem to change direction in the sky.

Answer 9

They don't. Earth does.