Cosmology
Modern cosmology is a child whose siring is credited to Edwin Hubble, the first person to show that there are other galaxies out there. For centuries, the thought was that what notion mankind had of his universe was the only one present; however, Hubble went on to show that the universe was vast and growing in his 1926 work, ‘the realm of the Nubilae’ (Hubble, P. 236). This finding broadened view of the world that man had thought was his entire universe and also opened new dimensions into our outlook of outer space and the world as it is.
Modern cosmology primarily refers to the developments concerned with the expansion of the universe, its origin billions of years ago, and the concept of dark matter. Some key aspects:
- The Big Bang Theory: This dominant framework explains the universe’s origin. It posits that the universe began with a rapid expansion from an extremely hot and dense state. Observational astronomy and particle physics converge in this theory, particularly through the Lambda-CDM model, which includes dark matter and dark energy.
- Homogeneity and Physical Laws: Modern cosmology assumes that the universe is homogeneous (on average, all places are alike at any time) and that the laws of physics are consistent everywhere.
- Historical Science: Cosmology is often called a “historical science” because when we observe distant objects in space, we’re effectively looking back in time due to the finite speed of light.
It is from these observations by early man that modern cosmology sprung from. From Aristotle to Ptolemy, to Galileo who was the first man to glimpse into outer space through the aid of an instrument other than the eye, the telescope, modern cosmology has had a lot to learn from the successes and mistakes made by those other theories and concepts that preceded it in that it had a basis to stand upon and theories to prove and disapprove.
The scientific discoveries since the time of Hubble have taken gigantic steps toward recognizing the world as it is, aided by advanced technology that enables scientists to view far off objects and determine their correlation with each other. As Adler (2006) says, the galaxies are like a the beads of a necklace, so many, expanding into a world that man with all his advanced technology has yet to glimpse.
The Big Bang Theory
Modern cosmology tries to explain the after effects of the Big Bang theory, but what exactly is the big bang theory? The Big Bang theory is what is described as the beginning of the universe. The universe is said to have sprung from a singularity, a form that defies all laws physics and what is harder to explain is where this singularity came from than what it did afterwards. It is believed that other forms of singularities abide in the black holes that are the voids in the galactic system our universe is part of (Hawking and Ellis, p. 25).
The Big Bang theory is described as the point when the form that came to be the universe started expanding rapidly, filling out, creating space and matter, and without adhering to the laws of physics as they are now, went on to form the universe as we know it today. It is still expanding.
The Cosmic Microwave Background (CMB)
The cosmic microwave background (CMB) radiation provides compelling evidence for the Big Bang theory. Here’s how it supports the theory:
- Origin: The CMB is electromagnetic radiation that fills the universe. It is a residual effect of the Big Bang that occurred approximately 13.8 billion years ago1. As the universe expanded, it cooled down, leaving behind this faint afterglow.
- Temperature: Deep space has a measured temperature of around 3K (3 Kelvin), not absolute zero. This temperature arises from the lingering radiation of the Big Bang. The CMB allows us to “map” the early Universe and study its properties.
- Accidental Discovery: The actual discovery of the CMB happened by accident. Scientists Arno Penzias and Robert Wilson detected excess radio noise coming from all directions in the sky. This isotropic radiation matched the predictions of the early universe’s thermal radiation field, supporting the Big Bang model.
The cosmic microwave background (CMB) radiation plays a crucial role in understanding cosmic structure. Here’s why:
- Seeds of Structure: The CMB provides a snapshot of the universe when it was just 380,000 years old. Tiny fluctuations in its temperature reveal density variations. These fluctuations acted as “seeds” for the formation of galaxies, galaxy clusters, and cosmic filaments over billions of years.
- Anisotropies: The CMB exhibits slight temperature variations across the sky. These anisotropies correspond to regions of slightly higher and lower density. They serve as the initial conditions for the growth of cosmic structures through gravitational collapse.
- Cosmic Inflation: The uniformity and isotropy of the CMB support the theory of cosmic inflation. This rapid expansion phase occurred shortly after the Big Bang, smoothing out the early universe and explaining why the CMB is so uniform on large scales.
The CMB provides a cosmic “fossil” that helps us unravel the origins of galaxies and large-scale structures. The CMB provides crucial evidence that the universe expanded from an initial violent explosion, confirming the Big Bang theory.
The Milky Way Galaxy
The Milky Way is just but part of the larger collection of galaxies. Its structure, once thought to be spiral has come to be described like an elongated bar that that supports that which has always been known as the spiral milky way. The Milky Way is thought to be composed of over thirty million stars, but dark holes and clouds of dust prevent proper assessment of the Milky Way.
The spiral-look that the Milky Way was thought to have is due to the fact that there are very bright stars at the center of the Milky Way and the light they send off give it a spiral look. Research and discoveries about the universe as it is has always had to come to terms with the spiritual side and powers of man. In that the forces that dictated the universe were attributed to the supernatural powers over the ages and were entrenched in the beliefs of man, modern Cosmology has met its skeptics just like the fore runners of astronomy faced over time.
The Milky Way is the galaxy that includes our Solar System. Its name describes the appearance of a hazy band of light seen in the night sky—a band formed from countless stars that cannot be individually distinguished by the naked eye.
Here are some key facts about the Milky Way:
- Structure and Size: The Milky Way is a barred spiral galaxy with an estimated diameter of 26.8 ± 1.1 kiloparsecs (about 87,400 ± 3,600 light-years). However, it is only about 1,000 light-years thick within the spiral arms (and thicker at the bulge).
Recent simulations suggest that a dark matter halo, containing some visible stars, may extend up to a diameter of almost 2 million light-years. The Solar System is located at a radius of about 27,000 light-years from the Galactic Center. - Galactic Center: The center of the Milky Way hosts an intense radio source known as Sagittarius A*, which is a supermassive black hole with a mass of approximately 4.1 million solar masses. The oldest stars in our galaxy are nearly as old as the Universe itself, likely forming shortly after the Dark Ages following the Big Bang.
- Discovery: Galileo Galilei was the first to resolve the Milky Way’s band of light into individual stars using his telescope in 1610.
Prior to the 1920s, most astronomers believed that the Milky Way contained all the stars in the Universe. However, observations by Edwin Hubble revealed that it is just one of many galaxies.
Context: The Milky Way is part of the Local Group of galaxies, which in turn belongs to the larger Virgo Supercluster and the Laniakea Supercluster.
The Milky Way is a vast cosmic tapestry of stars, gas, and dark matter—a breathtaking sight when we gaze at the night sky.
Modern cosmology is a million miles ahead of early man’s understanding of the universe. It scientifically explains the why and how based on scientific fact as opposed to the spiritual sense man in earlier times tried to explain the beginning of the universe through tales whose beginning eluded his imagination.
Touted as the most massive and expensive experiment in history, researchers in Switzerland drawn from all over the world have created a machine that is going to replicate conditions as they were after the big bang and collide opposing particles at conditions similar to those at the beginning. Critics have already filed lawsuits urging that the experiment be put to a stop with the argument the experiment will create a huge hole that will obliterate the earth and cause massive cosmic interruptions.
In a report by CNN (2010) on the experiment to recreate matter from the particles, the experiment has been dubbed a success. The experiment proves that matter flowed freely after the bang and supports the assumed big bang theory that this is the matter that went on to create what is today’s universe through expansion.
All in all, the cosmos is still remains a mystery, what is observed and passed as fact today might be looked upon tomorrow as false hood tomorrow, as the vast world in the outer space still remains a realm that man is yet to visit and verify the accuracy of his information. Just like modern cosmology did away with the beliefs held by the thinkers of the ancient and past times, greater advances in technology might lead to the changing of what the universe is really al about in the near future, either conform held beliefs or alter them.