Stellar Motion

Gaps between stars are thousands of times bigger than the distance between the Sun and Pluto, the most distant planet in the solar system. It is so far to the next star (Proxima Centauri) that light moving at 300000 km/s (186300 miles/s) takes 4.3 years to reach Earth. Near the Sun, the stars seem to have gaps of about 3-4 light years between them, and Proxima Centauri is just one of the couple of dozen or so relatively unremarkable stars within 10 light years of our sun.
The centre of our galaxy contains about 10 billion stars and the Sun and its neighbours are all moving through space as they orbit around it. In fact, relative to the Galaxy's centre, the Sun is moving at about 825000 km/h (513000 mph). While stars are going in the same general direction, they are not in the same orbit and so move relative to each other. Each star in the sky thus has what is known as a proper motion. This is the gradual change in its position against the stellar background, caused by the difference between its orbit around the centre of the Galaxy and that of the Sun.

Although the positions of the stars do change, the movement of most of them is almost imperceptibly slow. Changes can be measured only on photographs taken many years apart through powerful telescopes. The fastest moving star we can see is nearby Barnard's Star, a 9th-magnitude red dwarf in the constellation of Ophiuchus. This is the second closest star to our sun, at 6 light years away, and it moves across the sky by 10.3 arc seconds each year (one degree every 350 years). Most proper motions are many times slower than this. However, over long periods, the pattern of stars that make up the constellations will change because, by and large, constellations are change juxtapositions of bright stars in our line of sight from Earth, not physically linked groups that move together.
Familiar patterns of stars, such as the seven stars of the Plough or Big Dipper in the constellation of Ursa Major, can change slowly because of the proper motions of stars. A man who travels far into the future would be unable to recognize any familiar constellations in the night sky on "future" Earth.