Labels:text | screenshot | font | number OCR: COMET NUCLEUS THE SOLID CORE of a comet is called its nucleus. It is typically less than 20 km (12 miles) across and consists of ices embedded with dust grains. If the nucleus comes close enough to the Sun, it partially vaporizes to produce a glowing head of gases and one or more tails. The coma and tails may have dimensions of hundreds of thousands of kilometers and may be visible from the Earth.
