How Many Stars Are In the Sky?

Go out on a dark night and you’d swear there are thousands of stars in the sky — too many to count. Fortunately, you don’t have to guess or count. Astronomer Dorritt Hoffleit of Yale University compiled the Yale Bright Star Catalog decades ago, and it tabulates every star visible from Earth to magnitude 6.5, the naked eye's limit for most of humanity. So, how many stars are in the sky? The total comes to 9,096 stars visible across the entire sky in both hemispheres. Since we can only see half the celestial sphere at any moment, we necessarily divide that number by two to arrive at 4,548 stars — and that’s from the darkest sky you can imagine. While the total number of stars that can be seen by the naked eye may seem unimpressive, consider what happens to the sky in and around cities, where most of us live. If we account for city and suburban lights, we're left with just 70 stars worldwide, or 35 stars visible from say, downtown Chicago or Boston. No wonder city dwellers are stunned by the night sky when they take their first trip to the country. Stars barely exist for those trapped beneath an ever-present dome of light pollution.