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Alnilam of the Orion Galaxy Essay


People have been fascinated with stars and their motion since the beginning of time. Nowadays, the process has become impressively sophisticated, with a range of tools available. More importantly, the astronomic knowledge, which has been built over centuries, helps not only observe but also explain and predict the phenomena that can be observed in the sky. Although the calculations have to be approximated due to the imperfections in the technologies used, the outcomes of the project align with the existing theory, therefore, making it obvious that tracking the movement is highly possible due to its predictability.

Theory: Motion of Stars

When it comes to addressing the theory of stars motion, the Copernican heliocentrism (Dobrzycki 106) is typically brought up first. Being the first theory that shed some light on the way, in which planets moved, the specified theory implied that the Earth rotates around the Sun. However, the concept of stars motion emerged later.

Although the Copernican Theory did revolutionize people’s concept of the universe, it still did not imply that stars should move. Quite on the contrary, according to Copernican model, the Sun was supposed to remain motionless in the center of the Solar System, whereas the rest of the planets should be revolving around it. The rotation of stars, in its turn, was suggested as a feasible theory in 1910 by Eddington. Creating the model of a star, the researcher managed to shed some light on the nature of stars and the reason for their motion. Particularly, the scholar explained the very nature of stars, thus, designing the premises for numerous discoveries. In addition, Eddington suggested an entirely new means of classifying stars.

The Orion Galaxy and Alnilam

Also known as the Orion Arm (David 236), the Orion Galaxy is located in one of the arms of the Milky Way. The galaxy can be considered fairly small as it is only 1,100 parsecs across and 3,100 parsecs long. The Orion Galaxy includes the Solar System, i.e., the eight planets including the Earth. Therefore, though comparatively humble in its size, the galaxy bears an impressive significance for the humankind.

Alnilam, though not the largest star in the target area, clearly is one of the brightest and can be described as a supergiant. The temperature on its surface is very high, which ranks it as a blue-white star. Quite surprisingly for its temperature, the star is a supergiant with a considerably light spectrum, which makes it accessible for studying even for amateur astronomers. One must bear in mind, though, that the star is surrounded by a molecular cloud, which causes the star to lose mass at an increasingly fast pace. Perhaps, it is the cloud that the star owes its name to, which is translated as the string of pearls.


The observation of Alnilam was carried out by locating the star and observing the changes in its position. As the changes were spotted, they were registered on the chart provided in Appendix A. The alterations in the position of the star were registered five times a day throughout three days so that the pattern of its movement could be located easily. The time lapse made approximately two hours each day (from 7.30 p.m. to 9.36 p.m.). Although the time used for tracking down the movement patterns is rather small, when split into five stages, it allows seeing a paradigm.

The fact that the stars have been moving right also needs to be brought up. In the course of the observation, the star was watched facing south. As a result, the path that the star has made in the course of the observation can be defined as eastward. Indeed, assuming that the given statement is true, the reverse one will point to the fact that the star should move eastward: “For an observer on the earth, objects move from east to west (this is true for both northern and southern hemispheres). More accurately put, when looking north, objects in the sky move counter-clockwise” (“Paths of the Stars” par. 1). Consequently, if the process of observation had been carried out with the participant facing north and recording the process correspondingly, the movement of the star would have been identified as westward, i.e., the movement would have been headed left.

The results of the observation also point to the fact that the distances covered by the star in the course of nearly the same amounts of time do not necessarily correlate with the time taken. For instance, the difference in the 8.05 and 8.30 positions of the star is much greater than the one between the 9.03 and 9.36 positions correspondingly. The specified observation aligns with the existing concept of stars movement. To be more exact, the information retrieved in the course of the observation and pointing to the difference in speed can be attributed to the fact that Alnilam has a rather large parallax.

The phenomenon of parallax is typically defined as the difference in the actual position of an object and the one that it seems to have when viewed from a certain perspective (Angelo 445). Therefore, the observer located on the Earth is likely to see a certain space object not in its actual location but in the one that the angle between two different viewpoints suggests. The larger the parallax of a particular space object is, the greater the distortion between the actual position thereof and the one that is suggested by the observer on the Earth is going to be. The fact that Alnilam has a large parallax explains the difference in the distances covered by the star at similar time slots. While in reality, the distances must be practically similar, the outcomes of the observation suggest that the velocity of the object under analysis has changed several times (Hirshfeld 68).

The difference in the elevation of the star location as it was seen from the specified point can also be explained with the help of the existing theories of star movement. In fact, the concept of elevation as a combination of the altitude and the azimuth is typically identified as the “allows one to indicate any position in the sky by two reference points, the time from the meridian and the angle from the horizon” (“Celestial Sphere” par. 3) in the contemporary astronomy. Also referred to as the altitude, the phenomenon in question permits the exact location of the star when its data is combined with the index of the azimuth. Indeed, in accordance with the current theory of star movement, the altitude thereof changes as the star moves.

The phenomenon under analysis can be observed in the outcomes of the experiment; as the notes show, the altitude of Alnilam has been changing significantly over the three days during which the data was recorded. While the process of tracking down the location of the star began when Alnilam was comparatively low (approx. 45°), the further evaluation of its position showed that the altitude of the star has changed to about 60°. The observed phenomenon also aligns with the foundational principles of the theory of stars movement; particularly, the aforementioned concept of parallax is set into motion in the example above.


Despite insignificant inaccuracy in the calculations and the lack of appropriate tools for carrying out observations, the motion of stars was spotted as a result of an experiment and aligned with the tenets of the existing theory concerning the motion of stars. The changes in the location of Alnilam, a star in the Orion galaxy, displayed clearly that the current concept of star motion is easily traceable and can be proven with the help of consistent observations.

One must admit, though, that the outcome of the observation implied certain inaccuracies. As a result, deviations from the expected pattern of star movement could be located. The phenomenon under analysis can be attributed to the fact that the tools used for observing stars and their motion were imperfect and, thus, required approximation of results.

The experiment, therefore, has proven that the theory of star motion is true and can be used to identify the current position of a star and the changes thereof. The significance of the theory under analysis can hardly be overrated; shedding light on the laws of physics as applicable to the environment of the universe, they serve as the foundation for building strong theories and making essential discoveries.

Works Cited

Angelo, Joseph A. Encyclopedia of Space and Astronomy. New York, NY: Infobase Publishing, 2014. Print.

n. d.

David, Gary A. The Orion Zone: Ancient Star Cities of the American Southwest. Kempton, IL: Adventures Unlimited Press, 2015. Print.

Dobrzycki, Jerzy. The Reception of Copernicus’ Heliocentric Theory: Proceedings of a Symposium Organized by the Nicolas Copernicus Committee of the International Union of the History and Philosophy of Science Toruń, Poland 1973. New York, NY: Springer Science & Business Media, 2013. Print.

Hirshfeld, Alan W. Parallax: The Race to Measure the Cosmos. Mineola, NY: Courier Corporation, 2013. Print.

n. d.

Appendix A

Appendix A.
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IvyPanda. 2020. "Alnilam of the Orion Galaxy." August 29, 2020. https://ivypanda.com/essays/alnilam-of-the-orion-galaxy/.


IvyPanda. (2020) 'Alnilam of the Orion Galaxy'. 29 August.

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