Earth

Earth is the third planet from the Sun and is the largest of the terrestrial planets in the Solar System, in both diameter and mass. It is home to a myriad of species including humans.

Earth in "The Road Not Taken"
In 2039, a Roxolan invasion fleet arrived in the Earth's solar system. It was first detected by the crew of the Ares III, the third manned mission to Mars. The crew attempted to communicate but their radio signals were ignored and the Roxolan fleet proceeded to Earth since they had not detected any signs of hyperdrive. All vessels landed and deployed their foot to horrible effect.

Earth in Worldwar
The Race referred to the Earth as Tosev 3. They tried and failed to conquer the planet in the 1940s, which was already embroiled in a global conflict. While the Southern Hemisphere of the planet did fall rather rapidly, the Northern Hemisphere was able to fight the Race off and retain their autonomy.

For the next two decades, humans and the Race maintained a cold war, while both sides saw substanial a cross-pollination of cultures. Leaders of the Race frequently considered instigating a nuclear war with the dominant local powers to render the planet uninhabitable and destroy these influences, but before they made this decision the Tosevites had eclipsed them technologically, making this impossible.