Group D The Rocky Inner Planets
sourcethere are four planets that we call the rocky planets example mercury, earth mars and venus . In the Solar System, we have two groups of planets - the outer gas giants and the inner rocky ones. The rocky ones are the first four, which are much smaller and denser than the other four.

A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun. Terrestrial planets have solid planetary surface making them substantially different from gas giants, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.

The eight planets in our Solar System are divided into two groups – the inner planets and the outer planets. The inner planets are the first four planets closest to the Sun, which includes Mercury, Venus, Earth, and Mars. The outer planets are Jupiter, Saturn, Uranus, and Neptune. The inner and outer planets are separated by the asteroid belt, which is a region of space where thousands of asteroids can be found.The inner planets and outer planets are characterized by different features. The 4 inner planets are called terrestrial planets because they have a solid surface and are similar to Earth.

These planets are composed of heavy metal, such as iron and nickel and have few or no moons. Like Mercury, Venus has no moon. Earth is a rocky planet with a molten core, an atmosphere that allows life to flourish, and only one moon. The last inner planet, Mars, has two moons called Phobos and Deimos. It is a rocky planet with a red color caused by a high concentration of iron in the rocks that comprise the surface.

InnerPlanets2.jpg
http://www.ck12.org/ck12/images?id=339766
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License