Convert earth's equatorial radius to meter
Earth's Equatorial Radius
Earth's equatorial radius is the distance from Earth's center to its surface at the equator, equal to approximately 6,378.137 km (3,963.19 miles) as defined by the WGS 84 reference ellipsoid. Because Earth is an oblate spheroid, the equatorial radius is the largest radius and is about 21 km greater than the polar radius. It is a fundamental constant in geodesy, navigation, and geophysical sciences.
Meter
The metre (Commonwealth spelling and BIPM spelling) or meter (American spelling) (from the French unit mètre, from the Greek noun μετρούν, "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in 1/299,792,458 of a second.
The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted.