Audio Guide：

A comet consists of the nucleus, coma, and tail. The nucleus is composed of rocks, dust, ice, and frozen gases. The origin of these materials can be traced back to the time when the Solar System was just formed. The coma is formed when the comet passes near the Sun. Solar radiation causes parts of the comet to sublime, and the gases and dust released create a giant and sparse atmosphere that envelops the comet. The coma can often extend up to hundred thousands of kilometers. There are two types of comet tails. There are two types of cometary tail. The type that remains behind the comet’s orbit and appears yellow and white is called a dust tail. In contrast, an ion tail is pushed by solar radiation outward away from the Sun and forms a long, blue tail.

Use the model demonstrations and the touchscreen to learn more about comets.