Stars that appear in the sky move over time. This can be seen in these photographs which were taken in the space of few minutes. As seen from our earth, the stars appear to move in a certain direction. While the earth is orbiting the sun, it turns like a wheel. It is the turning of the earth that makes the stars appear to move.
Series photographs of stars can be taken over long hours during the night. A photographic technique is available to put these photographs into a single photograph. The result will give very beautiful patterns which capture star movements over time. These photographs are called star trails. We can see these beautiful star trails by searching the Internet.