The largest asteroid ever to hit Earth was probably Theia , a Mars-sized body that formed over 4 billion years ago, during the early days of the solar system.What are the four largest asteroids?
Four largest asteroids, scale artwork. The asteroids are seen against North America for scale. From left, from largest to smallest, they are: Ceres, Vesta, Pallas, and Hygiea. These asteroids make up around half of the mass of the asteroid belt, a large group of rocky and icy bodies orbiting in space between the orbits of Mars and Jupiter.