Wonders of the Solar System 第2集：从混沌到秩序

Beyond earth, the solar wind continues, creating dazzling aurora on other planets. Brian makes contact with Voyager, a probe that has been travelling since its launch 30 years ago. Now 14 billion kilometres away, Voyager has just detected the solar wind is beginning to peter out. But even here we haven't reached the end of the sun's rule. 　　Brian explains how its greatest power, gravity, reaches out for hundreds of billions of kilometres, where the lightest gravitational touch encircles our solar system in a mysterious cloud of comets.