A constellation is a pattern of stars that people have grouped together and named. When you look up at the night sky, you might notice that certain stars seem to form shapes: the ancient Greeks saw a hunter (Orion), a bear (Ursa Major), and a scorpion (Scorpius). Different cultures saw different patterns in the same stars and told different stories about them.

Astronomers recognize 88 official constellations that map out the entire sky like invisible puzzle pieces. These patterns serve a practical purpose: constellations help astronomers describe where things are in the sky, like using neighborhoods to explain where someone lives in a city. When astronomers discover a new comet or planet, they might say “it's in the constellation Gemini” so others know where to point their telescopes.

The stars in a constellation usually aren't actually close to each other in space. They just happen to line up from Earth's perspective. One star might be 25 light-years away while another is 500 light-years away, but from Earth they look like neighbors. It's similar to how two people standing far apart might line up perfectly in a photograph.

Before GPS and compasses, sailors used constellations to navigate across oceans. The North Star, part of the constellation Ursa Minor, always points north and helped travelers find their way for thousands of years.