Here's why:
* Earth's Rotation: The Earth spins on its axis, causing the stars to appear to move across the sky throughout the night. This is why we see different constellations at different times of night.
* Earth's Orbit: As the Earth orbits the Sun, our perspective of the stars changes. This means that the constellations we see in the summer are different from the constellations we see in the winter.
* Precession: This is a slow wobble in Earth's axis, causing the positions of the stars to change very gradually over thousands of years.
However, constellations do maintain their relative positions to each other. The stars within a constellation are so far away that their apparent positions remain relatively fixed over human lifespans.
So, while constellations appear to move across the sky and change with the seasons, the patterns formed by the stars within them remain constant.
