why do stars in constellations never change positions relative to one another, even over thousands of years?

Question

if everything is in motion, why is there no change?

Answer 1

The stars do move. Their motion is called "proper motion" and is tabulated by astronomers. Some simulations will show you that the big dipper will look nothing like a dipper in a million years or so. The reason we don't see the motion is that a typical star in the sky is around 100 light years away and, if it were moving 1,000,000 mph (not too unusual) it would drift 1/12 degree across the sky over an entire century. That's about 1/6th the diameter of the Moon. The motion is big enough to measure but too small to notice without sophisticated instruments.

Answer 2

Some good answers, so I won't intefere there, except the person who said the stars are millions of miles away. That is a gross understatement.

The stars are in the most part trillions of miles away.

The planets are millions and even billions of miles away and they are on our doorstep, relatively speaking.

Neptune is 3 billion miles away. The very nearest star is 10 thousand times as far.

People need to get space into their heads. Then they would understand simple questions like this one.

Answer 3

Because human lives are too short to measure the overall change. The stars do move in relation to each other, but it would take tens of thousands of years for the changes to be noticeable from Earth.

Answer 4

Stars are for the most part are millions of miles away. Even in a constellation the stars are light years away from each other. If a star was one million light years away from Earth and it blew up it would take one million years at light speed for people on Earth to see it with the naked eye. Light speed is really fast so you can imagine how far away and how long it would take for us to notice a change in a constellation we see today and have seen for thousands of years.

Answer 5

It takes thousands of years for the star motion to cause distortions of constellations. You can download certain skymap programs that allow you to enter dates thousands of years in the past or in the future:
http://skytonight.com/resources/software/3304926.html

You'll see how the constellations change and realize that these constellations only exist in our time. 10,000 yrs forward or backward, we would have had different constellations altogether.

Answer 6

The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding galaxy. The components of motion of a star consist of the radial velocity toward or away from the Sun, and the traverse angular movement, which is called its proper motion. Radial velocity is measured by the doppler shift of the star's spectral lines, and is given in units of km/s. The proper motion of a star is determined by precise astrometric measurements in units of milli-arc seconds (mas) per year. By determining the parallax of a star, the proper motion can then be converted into units of velocity. Stars with high rates of proper motion are likely to be relatively close to the Sun, making them good candidates for parallax measurements. Once both rates of movement are known, the space velocity of the star relative to the Sun or the galaxy can be computed. Among nearby stars, it has been found that population I stars have generally lower velocities than older, population II stars. The latter have elliptical orbits that are inclined to the plane of the galaxy. Comparison of the kinematics of nearby stars has also led to the identification of stellar associations. These are most likely groups of stars that share a common point of origin in giant molecular clouds.

Answer 7

One easy to find and example of proper motion of stars (actually in this case precession) is that Polaris is not quite over the North Pole. In a still motion camera shot showint star trails aroundthe pole, even the north star does. In 1950 it was over the north pole.

Answer 8

The planets are in motion, as well as all the comets and meteors and assorted other cosmic junk, but the stars stay in place. They act as the center of the solar system.
Therefore, you may see planets that move, but things like Orion's Belt will always be in the same place because it is composed of stars, not planets.

Answer 9

They do change! They are so far from us that their motion appears to be very slow. Everything out there is moving at great speed.

Answer 10

There is relative change. Thousands of years is nothing, a cosmic sneeze, in time.