What are the rocky, or terrestrial, planets?
Mercury, Venus, Earth and Mars are called rocky, or terrestrial, planets. They are similar to Earth in composition. Heat from the Sun evaporated lightweight elements like hydrogen and helium into interplanetary space. Mostly rock and metal were left in this zone. Eventually, it clumped together to form the inner terrestrial planets. Mercury, Venus, Earth, and Mars are called the rocky, or terrestrial, planets. They are the planets closest to the Sun. Their composition is similar to Earth’s composition, containing mostly the heavy materials of rock and metal. Because they formed closer to the heat of Sun, the lighter gases and ices could not condense during their formation, as they did in the outer parts of the solar system. | Back to Top | 11. What are the gas giant planets? Jupiter, Saturn, Uranus, and Neptune are called the gas giants. Jupiter and Saturn contain the largest percentages of hydrogen and helium, while Uranus and Neptune contain the largest shares of ices frozen water, a
