What Is Cosmology? A Short Introduction

Cosmology is a science that studies the cosmos as one entity, instead of breaking it down into different sections such as the stars, black holes and galaxies. Its main questions are concerned with where the universe came from, the history of stars, and the nature of galaxies. In essence, its aim is to decode the universe as a bigger image.

Cosmology vs Astronomy

While Astronomy studies the locations and actions of the planets and galaxies in space, Cosmology is more concerned with the structure, history, and evolution of the universe  on a general level.

As one of the oldest sciences, Astronomy can be said to be as old as humanity itself. It gave birth from humans wondering about the nature of space, when our ancient ancestors began to record the positions of stars and planets in the skies repetitively, which is known as orbital motion.

Astronomy deals with the study of stars and the solar system within the universe while cosmology is interested in the historical development of the universe. It is also interested in how time began, and whether it has a beginning. The universe’s creation, evolution and potential end are all points of cosmological study, and it does this by considering the universe as a single unit.

Historical Differences Between Cosmology and Astronomy

Astronomy began as a science that mainly produced calendars, only to develop thanks to the increased study of physical sciences in the 18th and 19th centuries. Its foundations lie in science very firmly.

Cosmology, on the other hand, is very theoretical and hardly possible to comprehend or study without a mathematical basis. It wasn’t until the early 21st century when facts such as the universe giving birth as a result of an explosion and that it never stops growing in size that cosmology began to take keen interest at a level of study.

Astronomy has a tendency to be concerned with the nature and properties of solar bodies like planets, stars, black holes, and galaxies, while cosmology focuses on the creation and potential end of the universe.

10 Cosmological Theories

Given that cosmology is an overly theoretical branch of science, it is packed with numerous theories. These are mainly speculations that are derived from scientists as well as scholars, causing us to delve deeper into the mysteries of the cosmos.

1. Time and Space are Superfluid

Perhaps one of the most hard to believe theories is that time and space are actually superfluid substances that do not necessarily flow with any friction. This means that if the universe is rotating, the superfluous of time and space are filled with vortices in the form of galaxies. Physicist Pawel Mazur of the University of South Carolina proposes that our universe might have been born in a collapsing star, wherein the combination of stellar properties and superfluid space create dark energy, resulting in the force that is causing the universe to expand.

2. Clashing Membranes

This is a hypothesis that suggests the universe is a membrane positioned in higher dimensional space, continuously clashing with another universe. A string theory called braneworld illustrates that there are various dimensions of space, and while gravity can be accommodated by them, we are restricted to experiencing our own universe that only has three dimensions.

Given the theory that the universe was created after clashing with another, there is speculation that these clashes repeat, creating a new explosion every now and then, indicating that if this pattern is correct then the universe could have no end.

3. The Goldilocks Universe

This concept relies on the fact that the universe has attributes that perfectly accommodate life? The slightest interruption in physical properties could mean there wouldn’t be any stars, matter, or a universe that lasts beyond a few seconds.

The anthropic principle colon illustrates that the universe is hospitable or else it wouldn’t be hosting us. This is supported by the theory of inflation which says that there may be an infinite number of universes, with an equally infinite amount of physical features and laws. However, cosmologists dismiss this anthropic notion as being non-science, because it makes no testable predictions.

4. The Cosmic Ghost Theory

This theory suggests that the mysteries of modern cosmology could be present in a ghostly presence. The concept of a ghost comes  After physicists made an adjustment to Einstein’s theory of general relativity, they noticed a peculiar material emerging, known as the “ghost condensate.”

The ghost condensate can create repulsive gravity that drives cosmic expansion in the big bang, producing a sedate increase that is linked to dark energy, which, if stuck together, could create dark matter.

5. The Fast Light Theory

The reason the opposite ends of the universe look the same is a puzzle because the extremes of today’s visible universe should never have been attached. Even during the birth of the universe, when the two ends of the universe were closer together, there wasn’t enough time for light to travel from one end to another.

Since there was no time for temperature and density to get evened out, it is surprising how they ended up being even. One proposal suggests that the reason for this is that light used to move much faster, but to focus on this would mean a revision of Einstein’s theory of relativity.

6. The Sterile Neutrinos Theory

There is a belief that dark matter is made of sterile neutrinos, which are considered to be heavier cousins of ordinary neutrinos that would interact with other matter only through the force of gravity. This would make them impossible to locate.

But the sterile neutrinos might have the right attributes to be warm dark matter, traveling at speeds of a few kilometres per second and creating dark matter collections that have been pointed out by recent observations. In addition, these neutrinos could help stars and black holes be created in the early universe, allowing for the push that sends neutron stars speeding around the galaxy.

7. The Matrix Theory

There is speculation that the universe isn’t real, and that we are probably living inside a computer simulation. If it were possible to simulate consciousness one day, then future civilisations would be experimenting with it.

If the universes experienced would be simulated ones, then the chances that we are in a simulated one increases, which could imply that properties such as dark matter and dark energy are glitches or early inconsistencies within our simulation.

8. Expansive Gravity Theory

This theory called Modified Newtonian Dynamics proposes that matter is not a physical property but a label for the odd aspect of gravity, and that gravity does not disappear as quickly as current theories suggest.

This stronger gravity can fill the role of dark matter, piecing together galaxies and clusters that would otherwise drift away. A new study focused on relativity, has redrawn attention to the concept.

9. Evolving Universes Theory

There is reason to believe that when matter is downsized to really small amounts in black holes, it expands and creates a new “baby” universe. Since the physical laws of the new offspring would be different, it may indicate that universes evolve.

Universes tend to create a lot of black holes which end up reproducing, causing them to dominate the area of the multiverse. Scientists are still trying to figure out if we live in a typical universe, meaning it has physical laws and constants that allow for the production of black holes.

10. The Small Universe Theory

This theory tries to understand the pattern of spots that are observed in the cosmos, which are only a few. It explains this by suggesting that the universe’s size is so small that while it was being created, it  wasn’t able to accommodate a lot of them, causing space to roll over on itself.

Some thinkers like to believe that the universe has the shape of a funnel, with one narrow end and one wider end. This shape of the universe would mean that the spots are being stretched out from rounder structures to more ellipse-like ones.

The Philosophy of Cosmology

Until 1960, cosmology was mainly observed as a type of philosophy. Since then, it has become a part of physics, namely due to its application to the birth of the universe which forms a part of atomic and nuclear physics.

Certain criteria deem the philosophy of cosmology very different to that of other sciences. One of them is the fact that the universe is a unique entity, meaning there is nothing to compare it with in terms of structure and properties. There is also the situation that since cosmology highlights the physical state of the universe, it does so within the context of human existence, since the universe’s state makes human existence possible.

In effect, while cosmology is a physical science, it is also a largely philosophical study due to its implications for human life.

Conclusion

While humans have traced the stars and wondered about the origin of the universe, it wasn’t until the early 20th century that scientists developed the first instruments and tools that would observe the universe in greater detail. This caused the big questions to turn into the study of what we now call cosmology.

Cosmology has the reputation of being more of a theoretical rather than practical science, assumed to be one of the oldest subjects of human interest but still developing a subject of study.

Cosmological study didn’t start until other physical sciences had developed, and so we expect for it to deliver us more answers as other sciences develop further, as a change to any of the physical laws could significantly change the cosmological story.

For now, we know that humans have attempted and to some extent understood the properties of the universe, and just the thought of our instinctive nature to ask such deep questions means that the answers are only yet to come!  

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