Here's why:

* Earth's Tilt: The Earth's axis is tilted at about 23.5 degrees. This tilt causes different parts of the Earth to receive varying amounts of sunlight throughout the year.

* Celestial Sphere: Stars appear to be fixed on a giant celestial sphere that we observe from Earth. Our perspective on this sphere changes due to Earth's rotation and orbit.

* Latitude: Your location on Earth (latitude) determines which stars you can see. For example, stars near the celestial poles will appear to circle around those poles throughout the night, but will never pass directly overhead (zenith).

Here's a breakdown:

* Stars near the celestial poles: These stars will never pass through the zenith for anyone on Earth.

* Stars near the celestial equator: These stars can pass through the zenith for people living within a specific band of latitudes.

* Other stars: Many stars are simply too far south or north to be seen from certain locations on Earth.

Conclusion: Only stars that are close enough to the celestial equator and within your field of view due to your latitude can pass through the zenith each day.