Naptune, the 8th planet outward from the sun, is now considered to be the solar system's farthest planet – now that Pluto has been demoted from planetary status by the International Astronomers Union.
因为国际天文联盟将冥王星降级至非行星行列，日外第八颗行星海王星，成为太阳系最偏远的行星。
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