Research Related to Galaxies And Stars

Galaxies are an interesting topic of discussion. There is so much about our universe that we have still yet to uncover. There are a number of galaxies that we can see with the use of modern technology but we have yet to fully investigate what is inside these galaxies. Our universe is filled with billions of galaxies, and from what we know, they are made up of a collection of dust, stars, and gases. They formed after our universe came into existence and have been discovered to be constantly moving through space. “…galaxy evolution is primarily determined by external effects that include hierarchical clustering and merging.” (Kim et al., 2017). What is intriguing about galaxies is the idea that despite all our advancements in our technology we have yet to crack open all that our universe has to offer. What we do understand is that stars, and the process of how they form has an effect on the galaxy’s evolution and shape. “…galaxies can be understood as resulting from different rates of star formation, the elliptical galaxies having turned most of their gas into stars at an early stage, while the late spiral and irregular galaxies have converted their gas into stars much more uniformly.” (Larson et al., 1978). Another intriguing idea, and fact about galaxies is the fact there is a high possibility of finding a supermassive black hole at the center.

We have only unlocked a small modicum of information that goes into the creation of our universe and its billions upon billions of galaxies. All the stars that have yet to be discovered, as well as hundreds or thousands of plants that may very well be inhabiting all of these galaxies surrounding our own. We know that star formation occurs in all of these galaxies at different rates through the collection and compression of gas. “The existence of a close connection between violent dynamical phenomena and rapid star formation is consistent with theoretical expectations that high-velocity collisions and shock fronts should be effective in compressing gas to high densities and triggering rapid star formation.” (Larson et al., 1978). There could possibly even be some of these planets may be capable of sustaining human life, but because our technology is not advanced enough, we still cannot know for sure. Because not all galaxies are the same, many tend to vary in their size and shape.

There are four different types of galaxies, which are Spiral, Barred Spiral, Elliptical, and Irregular. Our galaxy, the Milky Way, is that of a Spiral shape. All of these different shapes of galaxies are influenced by what surrounds them. If there is a galaxy close to another, that may have a stronger gravitational pull, it may very well influence the shape of its neighbor by either pulling or even pushing along it, possibly affecting its shape and formation.

Spiral Galaxies

Two examples of what the Spiral Galaxies may look like would include both the Milky Way and the Andromeda Galaxies. This galaxy form is made up of a large flat disk that contains spiral arms. As the name suggests, Spiral Galaxies tend to made up of bright young, hot stars. This specific form and shape of galaxies is one of the most common galaxy type scientists have identified. “A spiral galaxy’s halo is considerably more difficult to see than its bulge and disk because halo stars are generally dim and spread over a large volume of space.” (Bennett et al., 2015). The halos that are found within Spiral Galaxies are, more often than not, almost invisible as due to its large size, “…nearly invisible halo that can extend to a radius of more than 100,000 light-years.” (Bennett et al., 2015). As the name should suggest, Spiral Galaxies tend to consist of having a spiral like shape, that is constantly rotating. This is due to the strong gravitational pull that is being emitted from the center of the galaxy. This pull is what is seemingly pulling ‘holding’ the galaxy together. Scientists and astronomers have come to the conclusion that at the center of the Milky Way galaxy lies a supermassive black hole, which can help to explain the movement of the galaxy and the energy that is being emitted.

Barred Spiral Galaxies

Barred Spiral Galaxies, is another form of a spiral galaxy with a bar-shaped structure at the center of it. Like the other galaxies types it is filled with stars that are being formed. It is similar to the Spiral Galaxies, containing spiral arms as well. This can help explain why our Milky Way galaxy can double as both a Spiral and Barred galaxy, “Astronomers suspect that the Milky Way itself is a barred spiral galaxy, because of the elongation of our galaxy’s bulge.” (Bennett et al., 2015).

Elliptical Galaxies

Elliptical Galaxies are made up primarily of older stars, and are shaped more similar to that of a squashed sphere, or disk. These types of galaxies differ from Spiral Galaxies, as they have no spiral arms. In fact, Elliptical are different from Spiral Galaxies because of the way their disks are shaped. “Elliptical galaxies differ from spiral galaxies in that they do not have significant disks.” (Bennett et al., 2015). The light that emits from within Elliptical Galaxies, is that of much older and red stars that are present. These tend to be the most common ‘normal’ galaxies that can be seen and are typically smaller in size and less bright than other galaxies that can be found.

Irregular Galaxies

Irregular Galaxies are classified as such due to not having a ‘regular’ shape. Irregular Galaxies tend to have a much lower mass and Lumosity when compared to Spiral Galaxies. As their name should suggest they are often seen as being disorganized in shape and nature and are made up of both young and old stars. This category of galaxies tends to be considered as the as ‘miscellaneous’ due to all of their shapes and sizes being considered as ‘irregular’ and not capable of fitting into different categories filled by the other galaxy types that have been discovered. “These blobby star systems are usually white and dusty, like the disks of spirals, and contain many young, massive stars.” (Bennett et al., 2015).

Dwarf Galaxies

An interesting form or shape a galaxy can take, is that of Dwarf Galaxies. These galaxies are known to be either classified as Elliptical or Irregular in nature. They are called ‘dwarf’ because they tend to be much smaller than the other galaxies that have been studied, however like others they are made up of gas and stars that are undergoing formation as well. They are sometimes also known to be called ‘peculiar galaxies’, “Although peculiar galaxies only constitute a small fraction of the entire galaxy population, their existence conveys important information about how galaxies may have changed their morphologies during their evolutionary history.” (Mo et al., 2010). This goes to show that no matter the size, shape or structure of the galaxy, all are important and must be studied in order to find a better understanding of our universe past, present and hopefully future.

Galaxies are very interesting and complex topic of discussion. What is extremely fascinating about this topic is the amazing fact that because our universe is constantly evolving and expanding, there are more and more discoveries that are left to be made. Because galaxies are also moving all around us, closer, and farther. We can only hope to one day be able to travel to another galaxy to help confirm all our theories and suspicions about what truly lies behind the simple images we can see. Despite so many advances in our modern technology, it may very well be a long time before we can truly open up and dissect what every single galaxy in our universe contains and has to offer to our advancement in technology.

There is still so much we can learn from these unknown discoveries that have yet to be made, and there is no telling what we can do with the new-found information that we can only dream of at the moment. The prospect of seeing what truly lies beyond the boundaries of our own galaxy are limitless. In the future, we may be able to truly understand our universe on a deeper level, which will only help to provide us with a clearer picture of our existence on our single planet within this vast ocean of space.

References

Bennett, J.O., Donahue, Schneider, and Voit (2015). Essential Cosmic Perspective, 8th ed.
Fraknoi, A., Morrison, D., & Wolff, S. C. (2017). Astronomy. Houston, TX: OpenStax.
Kim, E., Hwang, H. S., Chung, H., Lee, G., Park, C., Sodi, B. C., & Kim, S. S. (2017). Star Formation Activity of Barred Spiral Galaxies. The Astrophysical Journal,845(2), 93. doi:10.3847/1538-4357/aa80db
Mo, H., Bosch, F. V., & White, S. (2010). Galaxy formation and evolution. Cambridge: Cambridge University Press.
Larson, R. B., & Tinsley, B. M. (1978). Star formation rates in normal and peculiar galaxies. The Astrophysical Journal, 219, 46. doi:10.1086/155753