The United Nations-Martian Congressional Republic War, also called the Earther-Martian War and referred to as the Little Interplanetary War, was a near-system-wide conflict between the two superpowers of the Sol system at the time, the United Nations and the Martian Congressional Republic. It was generally ignited by the contact between humanity and the protomolecule and the subsequent events, such as the Eros incident, when a protomolecule-infected asteroid managed to manipulate the fundamental force of gravitation, and the Ganymede incident, when the weaponizing of the alien entity resulted in the death of both Earther and Martian marines. Amazed by the seemingly physics-defying powers of the protomolecule, the two powers engaged into open combat in order to seize control of all of the extrasolar parasite, especially the Ring in its premature state, which was being built on Venus.