The Earth is third planet from the Sun and the fifth-largest of the nine major planets. The mean distance of the Earth from the Sun is 149,503,000 km. It is the only planet known to support life, although some of the other planets have atmospheres and contain water.The Earth is not a perfect sphere but is slightly pear-shaped. Calculations based on irregularities in the orbits of artificial satellites show that the Earth is an imperfect sphere, because the equator bulges, or is distended, by 21 km; the North Pole bulges by 10 m; and the South Pole is depressed by about 31 m. The Earth's only natural satellite is the Moon.

Van Allen Radiation Belts are two belts (sometimes considered as a single belt of varying intensity) of radiation outside the earth's atmosphere, extending from circa 650 to circa 65,000 km above the earth