Literature
What You Learn From The Stars (expanded)
The nearest star to Earth, save for the Sun, is Alpha Centauri, at approximately 4.24 light-years away, which means that it takes four years for the light to reach Earth. With the naked eye, a person can see stars up to the sixth magnitude after their eyes have become “dark-adapted,” that is, all sources of light must be eliminated and, after being in the dark for about twenty minutes time, a person can see stars up to that magnitude, and the estimated number of known stars that can be seen unaided is about six thousand in both hemispheres, so three thousand per hemisphere. The Andromeda galaxy is the furthest object in the nig