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地球是太阳系中九大行星之一,按大小排序居第5位,按距离太阳由近及远排序居第3位。日地距为14690万千米(一个天文单位),即8.3光分。它有一个天然卫星和若干人造卫星。其形状为两极稍扁平,赤道略鼓起的不规则的椭球体。平均半径6371千米,赤道半径为6378.140千米,极半径为6356.755千米,赤道半径比极半径长约21千米,北极半径比南极半径长约40米。地球扁率1/298.25。表面积51 000万平方千米,体积为10 832亿立方千米,赤道周长为40 073千
The Earth is one of the nine planets in the solar system. It ranks fifth in terms of size and ranks third in the distance from the Sun. The daily distance is 146.90 million kilometers (one astronomical unit), which is 8.3 light minutes. It has a natural satellite and several artificial satellites. Its shape is slightly flat, with irregular ellipsoids bulging slightly at the equator. The average radius is 6371 kilometers, the equatorial radius is 6378.140 kilometers, the polar radius is 6356.755 kilometers, the equatorial radius is about 21 kilometers longer than the polar radius, and the arctic radius is about 40 meters longer than the south pole radius. Earth flat rate is 1/298.25. With a surface area of 510,000 square kilometers, a volume of 1,038 billion cubic kilometers, and an equator circumference of 40,073 thousand