The sky is full of stars – but we can only see so many of them at night, and even fewer when the night sky is cloudy. Do you often look up and try to figure out what stars you are looking at (or if they are really planets)? Many people out there are fascinated by stars and constellations, after all. If you are a fan, you should be able to answer questions like what star is closest to Earth as well as which star is the brightest one in the sky! Want to put your star knowledge to the test? Take this quiz!