How do astronomers know how many stars there are in our Milky Way galaxy?
Many estimates in astronomy have some uncertainty to them, and the estimate of the number of stars in our galaxy is no exception. Even the world’s largest telescopes can’t count the stars. They see only the brightest and nearest stars – and stars not obscured by dust. To estimate the number of the Milky Way’s stars, astronomers first assume there’s nothing special about our region of space. They determine the number of different types stars in this region – then extend this knowledge to the galaxy as a whole. The most popular current models suggest the Milky Way is about 100,000 light-years across. The estimate for the number of stars is about 100 billion stars – plus or minus 50 billion.
