Cosmology :: Unraveling The History of the Universe

Cosmology is a scientific discipline combining astronomy and physics in an attempt to understand the universe as a whole, dealing particularly with the origin, nature, and evolution of the universe.

Cosmologists deal with ideas such as String Theory, Dark Matter, and Dark Energy. They wonder at the possibilities of a Multiverse, whether there our other Universes like our own, whether space is infinite, whether it is homogeneous (the same) in every direction, and what existed before there was material creation.

The Big Bang Theory is the work of cosmologists, dealing with the initial creation of matter which over time naturally under the impetus of Universal Laws formed into the living creation that we see here on Earth. Everything from the creation of the universe, to the creation of the galaxies, superclusters, stars, quasars, and chemical elements which populate it are of the domain of cosmology. The cosmologist ultimately studies the properties of the universe as a whole.

Cosmology :: The Story of the Universe

From the accumulation of scientific advancement over centuries, culminating in radical advances within the last century, we have arrived at a story of the creation of the universe at a clarity hitherto unparalleled. (Except by some advanced species at some point in time.)

The modern Big Bang Theory tells us that the entire universe was created at once. Space and time, the fabric of spacetime, came into existence across the entire universe in what from our perspective was but a single moment.

This occurred 13.7 billion years ago by the reckoning of earthlings. Since this point in time 13.7 billion years ago the universe has been constantly expanding. The rate of universal expansion has been known, though whether that rate will remain constant has been a matter of much debate as an answer to that question will give us an indication of how the universe will end. It will give us a piece of understanding the Life Cycle of a Universe.

The moment after the Big Bang the universe was incredibly hot, though it cooled quickly. The universe at this stage was composed predominantly of hydrogen atoms with a smaller concentration of helium atom. Though while we may say that there was less helium than hydrogen, this does not give a true impression of the quantities involved. All helium and hydrogen in existence today which makes up basically everything we see in material creation was initially created at the big bang.

An enormous, unimaginable amount of these two types of atoms were created. This provided the raw material which the Gravity, one of the Four Fundamental Forces, caused to collapse inwards forming ever larger masses which eventually became both the first galaxies, and the first stars.

The Birth of Stars

Matter across the virgin universe was being gravitationally attracted to all hydrogen and helium in its vicinity. Hydrogen and helium gas formed into giant space clouds called nebula, which eventually reached a sufficient density to collapse into a single star or innumerable stars, depending on the mass.

As hydrogen and helium fell into a single point of space, a young protostar formed. Gravitational forces pulled the infalling matter into a sphere. The core was the most dense. Friction, pressure, density, and weight of these particles continued to increase the further matter fell into the core extremely dense core, and the more matter that kept falling into the star.

Eventually the matter created a density and pressure due to gravitational forces which reached a critical level to ignite thermonuclear fusion in the core. The star begins to shine through the energy released by the collision of the nucleus of an unimaginable number of atoms. Two would fuse into one by a couple of processes, with the end result being the release of tons of energy in the form of light, and the formation of a new heavier atomic element.

Chemical Complexity & Generations of Stars

Stars were born and died in great generations, so that middle-age stars like our sun are of Generation III. Larger stars died in great supernova explosions which sent the elements (and the heavy elements they fused) flying through the galaxy which may enrich or form distant stellar nursery’s called nebula.

Each generation of stars literally fused material within the stellar core, fusing heavier and heavier atoms until the full 100+ chemical element diversity of the periodic table of elements is achieved.

This is an aspect of the evolution of the universe that brings to mind a likeness to a living entity. It reproduces, it grows, it evolves. Its creations all have rigidly defined life cycles, so wouldn’t the universe also? The universe literally forged within itself new material which made it more complex, enabling a more complex creation.

All of these developments lead to a sufficient chemical complexity existent on planets for life to eventually emerge within oceans due to dynamics of heat and density. All of these developments simply enriched the potential for life within planetary environments orbiting their stars, which themselves existed long before we believe life was possible due to natural star forming dynamics.

The End of Creation Told By Cosmology

In the fullest expression of cosmology, dealing with the end of the universe itself, no final, indisputable answer has yet been achieved. It is still being debated whether the acceleration of universal expansion will continue and expand towards infinity, or whether the mass of the universe is sufficient to cause a slowing in the rate of universal expansion leading towards an eventual catastrophic collapse of the entire known universe.

These are the two main camps of thought, yet there are some alternative, more holistic hypothesis.

On a smaller scale a definite picture has been achieved. From a study of the Life Cycle of Stars we have discovered that our Sun is an average, middle-aged yellow dwarf star. The Sun is around 4.5 billion years old. Though we know that in the next 5 billion years, a star of the type of the sun, will go through through a number of radical, ultimately natural changes that will render the Earth inhabitable.

This is an inevitable fact. Thus humans will ultimately need to learn enough about the universe in order to develop the technology to freely travel the stars, in spite of what our present science says is possible. Else we will go extinct as our star expands and radiates a portion of its material into the Galaxy.

These are a handful of the types of ideas, questions, and discoveries that have thus far been the fruit of the sub-discipline of cosmology, occupying the minds of cosmologists.

Further Reading

1. Popular Articles
   1. What is Cosmology? Definition & History | Nola Taylor Redd | 26 Sept | Space.com | Accessed 10 Sept 2020
2. Scholarly Articles