Observing the Sky Essay Example

Stars are balls of plasma that are made up of hot gas consisting of hydrogen and helium. It is important to note that stars are formed by the gravitational collapse of huge clouds of cold gas. When the cold gas is compressed, it eventually heats up and then transforms into plasma. The balls of plasma are what makes up the stars (Schwarzschild, 2015). The purpose of this essay, therefore, is to give the elaborate study of the stars by knowing what the stars are, the various types that exist, how they move and the relationship of stars with Kepler's laws of motion.

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It should be noted that the temperatures of the core of a star depend on its mass. When there is enough heat in the centre of the gas, there will be a nuclear fusion of hydrogen to helium, which will generate bundles of light energy known as protons. In as much as there is an untold number of celestial objects that are visible in the sky, some are known than others. Most of these known objects are the stars that can easily be seen with naked eyes because they are very bright compared to other objects in the sky (Schwarzschild, 2015). As a result, these stars have a long history of being observed and studied and occupy a significant section in the ancient folklore. Besides sun, therefore, there are other stars like Polaris which is also known as the North Star and is the 45th brightest star in the sky. Another star is the Sirius which is also known as Dog Star. This is because it is the brightest star in the night sky and even the brightest in Canis Major. Another example of a star in the sky is the Alpha Centauri System, also referred to as Rigel Kent and it is the brightest star in the southern constellation of Centaurus. It is, however, the third brightest star in the sky.

It is true that stars are much farther away than any distance that can be moved on the earth. This is the main reason why it is difficult to see them move in the sky. Undeniably, stars do move slowly throughout the night. There are two main reasons why the stars appear to move across the sky (Schwarzschild, 2015). Firstly, it is because the earth is spinning and secondly, it is because the earth itself is moving around the earth. It is worth noting that as the earth is moving around the sun, it spins on its axis once every day.

From Kepler's laws of planetary motion, there is more significant evidence of the relationship with the motion of stars in the sky. In his first law, Kepler stated that all planets move about the sun in elliptical orbits, where the sun is acting as one of the focal points (Katsikadelis, 2018). Just like the earth which spins around the sun in its orbit, the stars also move across the sky. This is propagated by the fact that the earth itself moves around the earth. From the second law, it is observed that a radius vector joining any planet to the sun sweeps out equal areas in an equal length of time. This relationship is also seen when stars move across the sky in the same length of time (Katsikadelis, 2018).

It cannot be denied that there are different types of stars in the sky. They range from tiny brown dwarfs to red and blue supergiant stars. Some of the examples of these stars are; Protostar which is formed before a real star is formed. It is a collection of gas that has collapsed from a giant molecular cloud. According to various studies, this phase of stellar evolution is believed to last for about 100000 years.

T Tauri Star is the next type of star. This is the stage of formation and evolution of a star before it finally becomes part of the main sequence star. It should be noted that this phase occurs at the end of the protostar phase, where the gravitational force holding the star together is the source of its energy. Notably, these stars do not have enough pressure and temperature at the core to help generate nuclear fusion. However, they resemble the main sequence stars.

Main Sequence Star. It is believed that the majority of stars in the galaxy are main sequence stars. Even the sun is a main sequence star as well as Sirius and Centauri. They can vary in mass, size, and brightness even though they do the same thing of converting hydrogen into helium in the cores to release energy. Another type of star is the Red Giant Star which is formed when the star consumes its stock of hydrogen in its core (Katsikadelis, 2018). There is also White Dwarf Star which is formed when a star has run out of hydrogen fuel in its core thereby lacking the mass to force higher elements into a fusion reaction. Such a star shines because it was once a hot star even though there are no fusion reactions taking place anymore. Al hence much cooler than stars like sun.so, there are Red Dwarf Star which are the common stars in the sky. They are main sequence stars even though they have low mass (Katsikadelis, 2018). Lastly, there are Neutron stars and Supergiant Stars which had already been discussed above.

Conclusion

While concluding, it is worth noting that stars are an essential part of our universe. They come in different sizes, colors, and varieties. This helps to know the different types of stars that exist, how the stars move in the sky, the relationship that the stars have between them. The essay further elaborated the relationship that the stars have with some of the Kepler's laws of motion.

References

Katsikadelis, J. T. (2018). Derivation of Newton's law of motion from Kepler's laws of planetary motion. Archive of Applied Mechanics, 88(1-2), 27-38.

Schwarzschild, M. (2015). Structure and evolution of stars (Vol. 2379). Princeton University Press.