Astronomy is one of the exciting subjects that predisposes us to gain more insights into interesting celestial objects that exist in the universe. Despite such aspects, astronomy is surrounded by a lot of unexplained mysteries, although it still serves as the primary avenue of helping individuals keep time and predict the future. One of the interesting objects that is part of the galaxies is the Milky Way. When analyzing the Milky Way, it is the central galaxy that constitutes the solar system. The Milky Way is also regarded as the most important galaxy to human beings since it serves as our home (4). However, when broken down, the Milky Way has other interesting facts worth uncovering. This essay, therefore, seeks to expound on the history of the Milky Way, its known features and characteristics, and some of the unanswered questions regarding it.
History
The Milky Way is one of the numerous galaxies that exist in the universe. In the ancient Aristotelian cosmology, the milky was often interpreted as a point where celestial spheres made contact with the terrestrial spheres. However, in 1610, Galileo made the first breakthrough when he observed individual stars through his telescope. According to Galileo, he observed that when he was viewing under his telescope, the Milky Way constituted a group of many stars (1). The Aristotelian cosmology in the first place upheld the idea that the Milky Way as a result of interactions between the celestial and terrestrial spheres. However, through his observations, Galileo noted that the Milky Way comprised a group of individual stars, planets, and several nebulae elements.
After Galileo had made his observations, other astronomers became interested and dedicated their efforts towards studying this object. One of the astronomers was Thomas Wright and he wrote a theory whereby he speculated that the Milky Way was a flat layer of stars, an essential aspect of the solar system (1). Wright also suggested that the faint nebulae that were evident were likely to be an external creation. Immanuel Kant also made his observations and noted that the faint nebulae viewed by Wright were island universes. The two notions brought by Wright and Kant have struggled to capture the implications associated with the new larger scale of the universe.
William Herschel and his son John Herschel also surveyed the Milky Way in the late 1780s and noted that the stars in the southern hemisphere were much denser when compared to those on the other sides. Harlow and Heber Cutis have also debated the nature of the Milky Way in the early 1920s (1). During this period, Wilson Hubble also used a 100-inch telescope to resolve the spiral nebulae. He concluded that they were stars, and most of them matched the standard patterns observed by other astronomers. Using the findings from the different astronomers, the Milky Way is one of the numerous galaxies that originated from a dominant scientific perspective (1).
Although the Milky Way is one of the most studied galaxies, most astronomers face different challenges directly observing it. One of the challenges relates to the function that piling plays onto supermassive compressed objects in the structure and evolution of the Milky Way. The Milky Way is believed to have a massive black hole known as the Sagittarius A*. With the Milky Way having the galactic nuclei, earth’s position, and a black hole, most astronomers have for a long time failed to see the center of the Milky Way (1). It took most astronomer’s centuries before discovering that the Milky Way had a spiral structure and the earth’s position also lay in it.
Known Features and characteristics
A large section of astronomers has made important discoveries concerning the properties of the Milky Way. However, understanding the story of their formation when the universe was also forming and how they have evolved for the past 13 billion years is still a challenge that most researchers struggle to uncover (3). The Milky Way is believed to be a barred spiral galaxy. When observed from below, it reveals that it has a central bulge that is bounded by four huge spiral arms. Since part of the earth sits on one arm of the Milky Way, it is not still but is continuously spinning. Additionally, the solar system and the sun move along the Milky Way (3). One unique aspect about the Milky Way is that it is bounded by a large halo of hot gas and stars.
The spiral arms at the center of the Milky Way contain a large amount of dust and gases. The last unique aspect of the Milky Way is that its center has a galactic bulge. This potion is filled with gas, dust, and stars (3). Due to the presence of the galactic bulge, it is one of the primary reasons that only a small percentage of the total stars can be viewed in the universe. The Milky Way also has got a black hole at the center. During its early formation, it was tiny; however, with the continuous supply of dust and gas, it has grown into a large hole.
Matters related to how the Milky Way and its components originated are still a topic of debate. However, the existing research indicates that the Milky Way galaxy emerged due to merging with other galaxies (3). During the formation of the Milky Way, its massive ass provided an avenue for the galaxy to spin at a relatively higher speed. As a result, this resulted in the collapsing of the gaseous interstellar medium, which was followed by the formation of stars in the spiral disk. The big bang theory also notes that the small particles condensed together during formation to form the stars, star clusters, and eventually the Milky Way (3).
Unanswered questions
The Milky Way is still subject to different researches by astronomers. However, various breakthroughs have been made, although some of them are subject to investigation by future scholars. One crucial aspect that is still unknown about the Milky Way is the inability to date different events in history of the formation of the galaxy, particularly events that took place during the early times (2). Much of this information is still unknown due to the increasing need for huge, high-resolution spectroscopic surveys of the relatively faded stars in the Milky Way. As a result, this challenge has made it impossible to determine the exact ages of various sample stars. Another essential aspect that is yet to be known relates to the accretion events before the Milky Way merged with the Gaia-Enceladus. Gaining insights into these two important events will help astronomers effectively link the events that took place during this period (2).
Conclusion
The universe has numerous celestial objects that are worth exploring. However, the Milky Way is much interesting since it also holds the planet earth where we live in. Despite most astronomers dedicating their time to studying the Milky Way, they have not managed to give one clear photo or an illustration of a complete Milky Way. Since new observations are still in place and constantly reveal new planets, stars, and facts, one day, a complete view of the Milky Way will be revealed by astronomers.
References
- Helmi, A. (2020). Streams, substructures, and the early history of the Milky Way. Annual Review of Astronomy and Astrophysics, 58, 205-256. https://www.annualreviews.org/doi/abs/10.1146/annurev-astro-032620-021917
- Marziani, P. (2015). Grand challenges in Milky Way and galaxies. Frontiers in Astronomy and Space Sciences, 2, 1. https://www.frontiersin.org/articles/10.3389/fspas.2015.00001/full.
- Massari, D., Koppelman, H. H., & Helmi, A. (2019). Origin of the system of globular clusters in the Milky Way. Astronomy & Astrophysics, 630, L4. https://www.aanda.org/articles/aa/abs/2019/10/aa36135-19/aa36135-19.html
- Sharma, S., & Sharma, R. (2020). Classification of Astronomical Objects Using Various Machine Learning Techniques. In Advances in Data Sciences, Security and Applications(pp. 275-283). Springer, Singapore.
