A major collision 4.5 billion years ago with the protoplanet Theia formed the Earth-Moon system and several additional moons
Most scientists agree that a major collision 4.5 billion years ago with the protoplanet Theia formed the Earth-Moon system. A new study from the University of Nevada argues that the chaos of that collision in the early days of the Earth-Moon system may have created polar cislunar “moons.”