Here's why:
* Earth's Orbit: As Earth travels around the Sun, our view of the stars changes throughout the year. Imagine looking at a distant tree from different angles – the tree itself doesn't change, but your perspective of its shape does.
* Different Seasons: During different seasons, we are looking out into space in different directions. This means we see different parts of the celestial sphere, making constellations appear to shift and change positions.
* Relative Positions: Constellations are made up of stars that are incredibly far apart, but they appear close together because we see them projected onto the same plane. Our changing perspective from Earth's orbit makes these stars appear to move in relation to each other, causing the perceived shift in constellation shape.
The constellations themselves are not physically changing. The stars within them remain in their relative positions in space, and they only appear to move due to our Earth's movement around the Sun.
