M级行星
M级行星
M级行星
M级行星又称类地行星， 是行星等级划分的。M 级行星出现在恒星的 "可居住区", 直径通常在 10,000~15,000 公里大气中含有氧及氮, 充满水及生物但若地表 97% 以上皆被水掩盖, 则归类为 N 级行星。典型的 M 行星包括地球，Cardassia and Vulcan。
英文原文：
Class M (Terrestrial):
Class M planets are found in a star''s "habitable zone" and are usually
between 10,000 and 15,000 kilometers in diameter. Their atmospheres contain
oxygen and nitrogen. Water and life-forms are abundant. If over 97% of the
surface is covered by water, then the planet is designated a Class N planet.
Examples of Class M planets include Earth, Cardassia and Vulcan.
相关分词：
行星