Comets - NASA Science
https://science.nasa.gov/solar-system/comets
WebComets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When frozen, they are the size of a small town. When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the Sun for millions of ...
DA: 49 PA: 59 MOZ Rank: 23