Audio Guide：

A nebula is an interstellar cloud formed by a cluster of interstellar medium such as gases and dust. Based on how they are formed, nebulae can be categorized into diffuse nebulae, planetary nebulae, and supernova remnants. When many stars converge into a group, they become a star cluster. Stars in a cluster were usually born at the same time; they are bound to each other by gravity. Star clusters can be classified into globular clusters and open clusters. Globular clusters are located in the galactic halo. They were created by hundreds of thousands to millions of old stars gathering into a spherical shape. Open clusters are located on the spiral arms and contain less stars. This results in a looser structure.

You can click on different nebulae and star clusters on the screen to learn more about them.