Sample Astronomy Essay Paper on Astronomy Picture of the Day

Astronomy Picture of the Day


The modern age is faced with worrying trend that is obscuring the beauty of the night sky. Industrial pollution in United States and Europe has made it difficult for individuals in this region to observe stars and other heavenly bodies in a clear night sky. Current studies have hinted that a child born in these regions has as less as one in every ten chance of witnessing a clear dark sky with stars and planets. However, there are ideal places where the Milk Way can be observed without the need Astronomical tools. This paper discusses a picture captured in one of the ideal places where a clear night sky is visible

Based on Astronomy Picture of the Day (APOD) posted on the NASA website (, this paper provides a detailed research about the picture of Galaxies from the Altiplano, posted on 13th, October 2016. Among many pictures that are posted by NASA on a daily basis, this was the picture that captured my attention. The picture was captured by Stéphane Guisard at Salar de Aguas Calientes a section of Flamencos National Reserve that hosts several salt flats of Chile. The pictures captures central bulge of the Milky Way Galaxy which escalates above the summit of northern Chilean Atacama Altiplano. It poses a clear dark sky with numerous stars, nebulae and cosmic dust cloud in the Milky Way Galaxy. Scientists and Astronauts have spent centuries studying galaxies because of the magnitude they bear.


The Milky Way Galaxy is the centre of the picture. The picture creates a visible impression of how galaxies look like. Galaxies are space systems comprising of billions of swirling stars, as well as dust, gas and other objects in the sky which are bound together by a strong gravitational pull. The earth is within the Milky Way Galaxy, which is just one among more than hundred billion galaxies in the universe. Because of the immensity it bears along with billions of stars and objects it carries, scientists are far from exhausting their discoveries on galaxies.  Scientists have been studying the galaxies for centuries. Current studies by great astronomers and scientists confirm that more than 90% of the galaxies in the cosmos have yet to be studied (Scoles 50). Astronomers have confirmed that there are galaxies which are far beyond the scope of telescopic observation. Analysing galaxies at these extreme distances and characterizing their features is a main aim of astronomers over the next decade.

Most astronomers believe that galaxies formed soon after a cosmic “big bang” that popped the universe nearly over 10 to 20 billion years ago. In the fractions of second following this bang, mass of gases began to merge, collapse, and compress under the influence of gravity to form the components of galaxies (Bertin 10). Scientists have been debating on how galaxies were formed first formed after the big bang. Some argue that minor clusters of about one million stars, referred to as globular clusters were formed first and later assembled into galaxies.

The Milky Way Galaxy is a very interesting occurrence in the universe. Not only does it house millions of stars and other objects, it is also the home to the planet Earth, which is regarded as the birthplace of humanity (Goldstein 66). The Solar System exists roughly 27,000 light-years away from the Galactic Centre, on the innermost edge of one of the spiral-shaped concentrations of gas and dust particles called the Orion Arm (Scoles 50).

The Milky Way Galaxy is spiral in shape. It has the shape of a disk with a thick and bright middle. From above, as observed via space telescope, the Galaxy appears like a spinning pinwheel. During clear nights, it is possible to view the Milky Way Galaxy. They normally appear as white band across the expansive sky. The word milk way originates from ancient Greeks, “gala”, which means “milk” (Bertin 13). They described the curvy path of numerous stars as a road of milk. They believed that this path joined the earth to the world of their gods.

In 1700, William Herschel, an astronomer from England used his telescope to view the shape of the galaxy. He counted the stars and drew a maps of the sky. From his research, he found out that the Galaxy was round but flat like a disk. He believed that the sun was positioned at the centre of the Galaxy. In 1900’s, an America astronomer Harlow Shapley discovered more details about the Galaxy. In his research, he noticed that one part of the sky contained the most stars. Unlike William Herschel, he believed that the part that contained most stars was the central part of the Galaxy. Currently, Astronomers believe that the Milky Way Galaxy may someday fuse with the Andromeda galaxy which is just two million light-years away and visible to the naked eye from Earth’s Northern Hemisphere.

Scientists have been using different processes to study and classify galaxies. By launching powerful satellites and conducting space missions, scientists are able to view and study galaxies better.  In experiments, galaxies emit all manner of electromagnetic radiations that range from x-rays to radio waves (Goldstein 68). From these emissions, astronomers are able to identify vital features that form the galaxies and at the same time capture pictures that can reveal the shape of galaxies. Before the modern technology, scientist used to study the stars and galaxies using telescopes from the confines of their labs. In the recent years, space telescopes such as Hubble Space Telescope have been launched to help in providing vital cosmic data from the space (Reddy 32). Consequently, as a result of these advances, scientists have been able to classify galaxies. The most commonly used classification order for galaxies is based on the one developed by Edwin Hubble and further advanced by astronomer Gerard de Vaucouleurs. The classification makes use of the three main types, which are further broken down by precise characteristics such as; openness of spirals, proportions of galactic bulges, proportions and extent of bars. Therefore, there are three main types of galaxies: irregular, elliptical and spiral galaxies (Reddy 31)

Spiral galaxies, as the name indicates, are spiral in nature. They are the most common galaxies in the universe. The Milky Way where the earth inhibits is a spiral in shape (Reddy 30). Andromeda Galaxy which is closest to the Milky Way has a spiral shape. The bright section at the centre of a galaxy is referred to as galactic bulge. Several spiral galaxies have a halo of stars and star clusters arranged above and below the disk. The disk comprising of stars, objects, planets, dust, and gas spin around the galactic centre in an even manner (Goldstein 69). This rotating motion may cause substance in the disk to take on a typical spiral shape like a celestial pinwheel. Other spiral galaxies gain even more interesting forms that earn them descriptive titles, such as sombrero galaxies. It is believed that older stars occupy the bulge at the centre of the huge disk. Many other new stars also form in spiral scheme.

The other type of galaxies is elliptical. Elliptical galaxies assume the shaped suggested by their name. This type bears the universe’s largest known galaxies, which are thought to be as much as two million light-years long (Scoles 51). They are generally egg-shaped or ellipsoidal in nature. They are normally round but elongate along one axis than along the other. Most elliptical galaxies contain trillions of many older, low-mass stars but with little dust and other and other interstellar matter. Astronomers currently believe that every elliptical galaxy has a core of supermassive black hole that relates to the mass carried by the galaxy itself. One example of elliptical galaxy is Messier 87.

Galaxies that are not classified as spiral or elliptical are referred to as irregular galaxies. Irregular galaxies seem distorted and lack a discrete shape, often because they are distorted by the gravitational force of other galaxies close to them.


The picture discussed in the paper present significant features in Astronomy. There Milky Way is the most interesting feature that has been captured in the picture. The picture depicts great achievements that have been made by Scientists and Astronauts concerning the Milky Way Galaxy. Much of what has been discovered has been discussed have been discussed above. More discoveries are expected in the near future to clear uncertainties about what occupies the central part of the galaxy. Though Milky Way Galaxy was discovered long ago, significant advance about it have been made and new discoveries have been made through modern technology.

Work Cited

Bertin, Giuseppe. Dynamics of galaxies. Cambridge University Press, 2014.

Goldstein, Alan. “Finding Our Place in The Milky Way.” Discover 37.4 (2016): 66-69. Academic Search Premier. Web. 14 Oct. 2016.

Reddy, Francis. “Earth’s Home Galaxy.” Astronomy 43.12 (2015): 30-35. Academic Search Premier. Web. 14 Oct. 2016.

Scoles, Sarah. “Our 100,000 Closest Galaxies.” Astronomy 43.12 (2015): 50-55. Academic Search Premier. Web. 14 Oct. 2016.