The apparent position of star constellations in the night sky remains relatively unchanged over human timescales, even though Earth orbits the Sun and moves to the other side of the solar system every six months. This phenomenon is due to the vast distances between stars and the tremendous scale of the universe.
When we observe the stars from Earth, we are effectively viewing them from a fixed perspective within our own solar system. Although Earth's orbit around the Sun takes us to different positions in space, the stars are so incredibly far away that their positions relative to one another appear nearly unchanged over the span of human history.
To illustrate this, consider the distance to the nearest star to our solar system, Proxima Centauri, which is about 4.24 light-years away. A light-year is the distance light travels in one year, roughly 9.46 trillion kilometers (5.88 trillion miles). The vastness of this distance means that even as Earth moves along its orbit, the changes in our perspective are minuscule compared to the vast separation between us and the stars.
So, while we experience different views of the night sky throughout the year due to Earth's orbit, the overall configuration of the star constellations remains relatively unchanged from our vantage point. This consistency is what allows us to recognize and identify familiar constellations that have been observed for thousands of years.