This led to the formation of the terrestrial planets—Mercury ... in the protoplanetary disk to form such a planet. This finding suggests that gas giant planets can form around a wider range ...

Terrestrial planets include Mercury ... They are sometimes called gas giants because they are large and made mostly of gases. Small amounts of rocky materials are only found deep in the cores ...

A year on Uranus is 42,718 Uranus days long! Between the orbits of the terrestrial planets and the gas giants, there are millions of asteroids – rocky objects that orbit the Sun and vary in size ...

Large and small planets are born from very different circumstances, according to data from NASA’s now-retired space telescope ...