冥王星是太阳系里第九颗大行星,这已是人们熟悉的常识.但是,如果有人告诉你,它可能不是一颗行星,你一定会惊讶吧!确实,它的许多令人费解的行为,已经引起了天文学家们的争论. 发现趣闻自从赫歇尔用望远镜发现天王星以后,天文学家又通过计算发现了海王星.本世纪初,人们发现海王星的实际运动和计算的结果不一样.由于过去海王星的启示人们不禁又想:海王星外是否还有一颗行星呢? Pluto is the ninth largest planet in the solar system. This is common sense. However, if someone tells you that it may not be a planet, you will be amazed! Indeed, many of its puzzling behaviors It caused controversy among astronomers. Interesting Facts Since Herschel discovered Uranus with a telescope, astronomers have also discovered Neptune through calculations. At the beginning of this century, people discovered that the actual movement of Neptune is not the same as the calculation. Because of Neptune’s past Revelation People cannot help but think: Is there a planet outside Neptune?