Terrestrial vs. Jovian Planets

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The word planet is derived from the ancient Greek word planetes, or “wanderers.” Though the visible planets of that time did appear to be wandering in the sky, the science of Astronomy has broadened this term as well as our understanding of what, in fact a planet is. By modern definition, “planet” is described as a celestial body other than a star, which orbits a star. Our Solar System orbits the center of our home galaxy, the Milky Way, and has a rich and varied structure. It consists of the Sun, four small inner planets, four outer gas giant planets, and the distant, but small planet Pluto. These planets do not wander erratically; instead they are inherently orbiting the Sun. The delineation of these planets do not end at their identification, rather they are subcategorized as being either Terrestrial Planets or Jovian Planets, with the notable exception of Pluto, which is neither. Terrestrial Planets are the four innermost planets closest to the sun, respectively Mercury, Venus, Earth and Mars. These are the planets that most resemble the Earth, although Earth is the only known planet with the ability to sustain life. All four planets are rocky in composition have metal cores and solid surfaces. Due to this fact, they gain their name terrestrial from the Latin word terra, meaning "land" or "earth." All the terrestrial planets orbit the Sun and rotate on their own axes in the same direction, with the exception of Venus which rotates counterclockwise. The Jovian planets, Jupiter, Saturn, Uranus, and Neptune are the four planets furthest from the Sun. These planets are regarded as jovian due to the “jupiterlike” qualities they possess. In contrast, they all differ greatly from the Terrestrial Planets in regards to size, composition and density. In addition, unlike the rocky, “earthy” Terrestrials, Jupiter, Saturn, Uranus and Neptune are far larger in size and far less dense which is primarily due to their elemental composition. The Jovian Planets are...
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