Earth (or Sol III or Terra) is the inhabited third planet of the Sol system. It was a M-class planet and had a single natural satellite, Luna. Earth was the homeworld of the Humans and the Voth, amongst others, and was the capital planet of the United Federation of Planets.
In 2150, with the last nation-states joining, the planet was unified under the United Earth government. It was a founding member of the Coalition of Planets in 2155, and of the United Federation of Planets in 2161. The President's office, the Federation Council, as well as Starfleet Headquarters and the main branch of Starfleet Academy were located on Earth. During the Dominion War, Earth's strategic importance was on par with worlds like Andor, Berengaria VII, and Vulcan.
Earth was a spheroid-shaped planet with a circumference of 24,874 miles (40,075 kilometers), a mass of 5.8×1024 kilograms and a mean density of 5.517. Its atmosphere had an average temperature of 75 °F (24 ºC) and consisted of 78% nitrogen, 21% oxygen as well as smaller percentages of krypton, neon, and argon.