上游充通大￥ Shanghai Jiao Tong University Earth Facts .Distance from Sun:150 million kilometers (93.2 million miles) .Orbital period:365.256 days .Rotational period:23.9345 hours .Tilt of axis:23.45 degrees .Diameter:12,756 kilometers(7,973 miles) .Mean density:5.515 g/cc .Mean surface temperature:15 C .Atmospheric pressure:1.013 bars .Atmosphere composition:77%N,21%O and 2%other. .Crustal rocks:Mid-ocean ridge basalt,andesites,granites, sandstones,shales,limestones,metamorphic. .Magnetic field .Plate tectonics .Hydrosphere Biosphere From epswww.unm.eduShanghai Jiao Tong University •Distance from Sun: 150 million kilometers (93.2 million miles) •Orbital period: 365.256 days •Rotational period: 23.9345 hours •Tilt of axis: 23.45 degrees •Diameter: 12,756 kilometers (7,973 miles) •Mean density: 5.515 g/cc •Mean surface temperature: 15°C •Atmospheric pressure: 1.013 bars •Atmosphere composition: 77% N, 21% O and 2% other. •Crustal rocks: Mid-ocean ridge basalt, andesites, granites, sandstones, shales, limestones, metamorphic. •Magnetic field •Plate tectonics •Hydrosphere •Biosphere Earth Facts From epswww.unm.edu