The main reason we don't see most of the stars in our galaxy is due to the vastness of the universe and the limitations of our perception.
Firstly, the Milky Way galaxy is a flattened, disk-shaped structure with a diameter of about 100,000 light-years. It contains an estimated 100 to 400 billion stars. The density of stars within the galaxy is not uniform; they are concentrated in certain regions, such as the galactic bulge and the spiral arms, while other regions have relatively fewer stars. This non-uniform distribution means that we have a limited line of sight to observe all the stars within the galaxy.
Secondly, our view of the universe is restricted by various factors. One major limitation is the presence of interstellar dust and gas within the Milky Way. This dust scatters and absorbs light, leading to a phenomenon known as interstellar extinction. This extinction reduces the brightness and visibility of distant stars, making them harder to observe.
Additionally, Earth's atmosphere also plays a role in limiting our view of the stars. Atmospheric turbulence and light pollution from human activities can hinder our ability to see faint stars and objects in the night sky. That's why observatories are often situated in remote locations with clear skies to minimize these effects.
Moreover, our human eyes are limited in their ability to perceive faint objects. We have a certain threshold of sensitivity to light, and beyond a certain distance or faintness, stars become too dim to be detected by the naked eye. Telescopes, on the other hand, can gather more light and reveal fainter objects that are not visible to the naked eye.
Taken together, the vastness of the universe, the distribution of stars within the galaxy, interstellar extinction, atmospheric effects, and human visual limitations all contribute to the fact that we can only observe a fraction of the stars in our own galaxy, the Milky Way.