The solar system is a system that comprises of the sun and the astronomical bodies which are bound gravitationally in an orbit around the sun (Gardner, 2005). They formed from the residues of the collapsed giant molecular cloud. The orbits of these planets are circular and lie within an elliptic plane. The four smaller inner planets are known as terrestrial planets, while the other four large outer planets are referred to as Jovian planets (Gardner, 2005). The solar system also consists of a number of regions that are occupied by smaller objects. The layers include the asteroid belt which lies between mars and Jupiter. Another region is the kuiper belt which lies beyond Neptune (Gardner, 2005). This paper has analyzed the nature and characteristics of these planets in part one.
- To describe the early geocentric idea of the universe according to the Greeks
- Explain how the work of five modern scientists changed our way of thinking about the Earth, the planets, and space
- To compare the two groups of planets in our solar system in relation to their characteristics
- To describe the features of the moon
During the mediaeval period, the ancient Greeks had an understanding that the earth was a stationery body. According to the archaic astronomers, most of them believed that the earth was not in motion at any point and it formed the center of the universe (Gardner, 2005). Despite the fact that there were no instruments and apparatus to perform any research, they were capable of analyzing the earth behavior and managed to produce theories that were supported by facts that relied on basic human observation (Gardner, 2005). They believed that the earth was stationery due to the fact that people had no feeling of motion, and also due to the argument that people were not falling off the earth (Gardner, 2005).
The minor members of the solar system include the Dwarf planets. The Dwarf planet consists of the Pluto, which can be seen with the aid of special instruments. It is much smaller than the moon, triton, titan and the Galilean moon (Gardner, 2005). The other family of the dwarf planet is the Ceres. This is the largest object in the asteroid belt.
An asteroid is another member of the minor solar system. It mostly occurs between mars and Jupiter. It also consists of small bodies, and some of the bodies have very eccentric orbits (Gardner, 2005). They contain irregular shapes with 75% carbonaceous chondrite and 17% nickel iron silicate. Its total mass is a half that of the moon (Gardner, 2005).
For many decades, human beings could not recognize and describe the existence of the solar system. They had a strong believe that the earth was stationary and located at the centre of the universe (Gardner, 2005). Nicolaus Copernicus was the first scientist to develop a mathematically predictive heliocentric system. Later, Galileo Galilei was able to develop a telescope that could be used to observe the space bodies. Johannes Kepler and Isaac Newton eventually developed an understanding of physics that led the gradual acknowledgement of the fact that the earth orbits around the sun and the planets are also governed by the same laws that govern the movement of the earth (Gardner, 2005).
According to current research, it’s considered that there are two groups of planets namely: Jovian and terrestrial planets. In order for a planet to fall into the class of Jovian planets, the planet should be extremely large in size. Its diameter should be 4 times greater that of the terrestrial planet (Gardner, 2005). A planet will be classified as terrestrial only if it is small in size and possesses an earth like structure with a diameter less than one quarter of the Jovian planets. Jovian planets include Jupiter, Saturn, Uranus and Neptune while terrestrial planets include Mercury, Venus, Earth and Mars (Gardner, 2005). Stellar parallax is simply the difference in direction of a celestial object as seen from two widely separated points by an observer (Gardner, 2005). It is also considered as a parallax effect on a distant star in astronomy. It is calculated mathematically using the formula:
p = parallax angle in arc seconds
d = distance in Parsecs
On writing the parallax formula in this form allows us to define and describe the new unit for distance in astronomy known as the parallax- second or commonly referred to as the Parsec (Gardner, 2005).
The only natural satellite that the earth consists is the moon, which is also the fifth largest satellite in the solar system. Its diameter is approximately one quarter of the earth. It is the second densest satellite after a satellite that belongs to Jupiter referred to as lo. The moon is in synchronous rotation with the earth and always showing the same faces (Gardner, 2005).
The closest side of the moon to the earth is marked with dark volcanic known as Maria, which is situated among the bright ancient crustal highlands and prominent impact craters (Gardner, 2005). Apparently, moon is the second brightest object in the sky after the sun. Its outer most surfaces are dark, with a similar reflectance to coal. The moon consists of lunar water in form of ice in its permanently shadowed craters at the poles and bound into the lunar regolith (Gardner, 2005).
There are three types of galaxies namely the Elliptical, Spiral, and the Irregular. The Elliptical galaxies contain a spheroid shape. They tend to appear oval shaped disks. They possess a smooth light with its surface brightness decreasing as one move farther out from the center (Gardner, 2005).
The spiral galaxies contain three main features. It has a bulge which is spherical in structure and found at the center of the galaxy (Gardner, 2005). It also comprises of the disk which is made up of dust, gas and younger stars. Its halo is a loose spherical structure located around the bulge and some of the disk (Gardner, 2005). An example of a spiral galaxy includes the Milky Way.
Another prominent family of galaxies is the irregular galaxies which do not possess a regular or symmetrical structure. It contains a region of elemental hydrogen gas and many population stars, which are young and hot (Gardner, 2005). They also have a thick layer of dust that blocks the light from its stars making it difficult to see distinct stars in the galaxy.
Contrarily with other satellite bodies, the star undergoes evolution and is transformed through various stages which include: nebula, star, red giant, red dwarf, white dwarf, supernova, neuron stars and finally the black holes. During the nebula stage, it is basically a cluster of hydrogen gas and dust in space (Gardner, 2005). During this stage, the star shines dazzlingly because the gas that it possesses is energized by the stars that have already formed within it. In the star stage, it is a glowing globe of gas generating its own heat and light by nuclear reactions. When it transforms to a red giant, it is more of a large intense star with a cool facade. It is usually formed during the later stages of the evolution of a star just like the sun (Gardner, 2005).
Big bang theory offers human beings an explanation of what happened at the beginning of the world. According to the conjecture, the cosmos came into existence as singularity, approximately 13.7 years ago (Gardner, 2005). The theory asserts that the universe begun with less heat, very small and extremely dense. After sometime, it magnified, stretched and cooled. It became very minute and very hot to the size and the temperature of our current earth. It continues to get bigger and cool to this day (Gardner, 2005). Absurd creatures living on an inimitable planet, rotating an outstanding star bound together with several galaxies.