Comets are quite the celestial spectacle. Would you believe that they are simply pieces of dusty ice?
When a comet flies close to the Sun, some of its ice turns into a long, bright trail, or tail, of vapor. That tail is a comet's most amazing feature.
Most comets are unpredictable. Astronomers can calculate where one will be in the sky, but not how bright its tail will be. Probably the most famous one, Halley's Comet, appears every 76 years—but it doesn't always make a great show.
Halley's Comet was spectacular in 1910 and disappointing in 1986. In 2061, it will be large and visible in the Northern Hemisphere. Let's hope that the sky is clear!