Origins, Modifications, Similarities and Differences of Terrestrial Planets
Terrestrial planets are the first four planets from the sun and they are spherical in shape with their surface composed of rocks (Howell, 2018). Only Venus, mars and earth have a significant atmosphere with mercury having no atmosphere. During the initial formation of these planets, light gases accreted on them. These light gases were hydrogen and helium. However, these primary gases have escaped because of their light mass, escape velocity and surface temperature of these planets. Others have been incorporated in oceans, rocks and UV light. However, heavy gases like N2, CO2, and O2 can be traced to a large percentage.
This atmosphere has been modified over time because of the distance of these planets from the sun. Venus became too hot that it leached carbon dioxide embedded in rocks into the atmosphere. The similarity of these three is that they have carbon dioxide which plays a different role in each. However, these planets are different in the atmospheric composition ("Solar System Review," n.d.). Venus’ atmosphere is very dense mostly composed of CO2 and clouds of SO2. Earth atmosphere is composed of N2, CO2, and O2. Mars (red planet) has a thin carbon dioxide atmosphere embedded with water ice in the poles.
Composition, Similarities, Differences of Jovian Planets’ Interiors
Jovian planets are Saturn and Jupiter (gas giant) as well as Neptune and Uranus (ice giant) planets. All the interiors of the four Jovian planets are composed of hydrogen, rock and metal compounds. The main differences are within their layers surrounding the core as shown in the figure below ("Outer Planets: Giant Planets: Interiors," n.d.). The reason for differences is because of pressure, temperature and density variations from the cloud tops. These planets also induce internal heating from the sun and from within their core bringing about contraction to the internal structure.
Jovian planet Interiors
Terrestrial Planets’ Surfaces and the Processes behind Their Modification
The processes that bring changes to the surfaces of the terrestrial planets are impact cratering, tectonic activity and erosion. Impact cratering is large in planets with old surfaces (Mercury) while planets with young surfaces (Neptune) have less evidence of cratering. Tectonic activity varies with the amount of heat that was stored in the planet after formation. Thus the planets with a huge mass imply that it stored a large amount of energy during its formation e.g. earth. Earth is the most active planet in tectonic activity ("Solar System Review," n.d.). The other three are less dense compared to earth thus they have little volcanic activity. The higher the tectonic activity, the higher the erosion rate. Earth has, therefore, a more rugged surface compared to the three.
Variations of the Gas Giant Moons/Galilean Moons of Jupiter
Galilean moons are the 4 giant moons of Jupiter: Calisto, Ganymede, Europa, and Io. They were first discovered by Galileo Galilei in 1610 after modification to his telescope. They all revolve around Jupiter and have a tidal lock with Jupiter. They are also spherical in shape as compared to other irregular moons of Jupiter. Ganymede is the largest of the four and also the largest in the solar system ("Solar System Review," n.d.).
The Regions in the Solar System
There are two regions of the solar system: inner region comprising of the first four planets and the outer region comprising of the other planets (Knight, n.d.). These two regions are divided by the asteroid belt. The Kuiper belt houses all the dwarf planets and other objects which resemble planets. The ort region houses all comets. However, little information is known about Kuiper and ort regions.
Howell, E. (2018). What Is a Planet? Retrieved from https://www.google.com/amp/s/amp.space.com/25986-planet-definition.html
Knight, J. (n.d.). The Solar System - Tour the Solar System on Sea and Sky. Retrieved from https://www.seasky.org/solar-system/solar-system.html
The Outer Planets: Giant Planets: Interiors. (n.d.). Retrieved from https://lasp.colorado.edu/education/outerplanets/giantplanets_interiors.php
Solar System Review. (n.d.). Retrieved from https://abyss.uoregon.edu/~js/ast121/lectures/lec08.html