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An in depth look at the states and galaxies

Life is solely dependent upon the stars and the galaxies in which they make their home. The sun is the central engine which fuels life on our planet. Without such amenities life as we know it would not exist.

  • As the gas cloud condenses it gets a vigorous rotation;
  • As the cloud of gas is pulled together, it becomes more dense and opaque.

It is easy to realize the importance of the processes of the formation of galaxies and stars, particularly our own, when looked at from this perspective. The processes and variables that were present in the creation of the galaxies and stars shed light on the formation of the universe in its present and future state.

The heavens that look so familiar to us are actually an ever-changing and dynamic environment. Galaxies and stars form, evolve and change as surely as we do over our lifetime. This life span is on a far greater scale, however, than we can easily fathom. Whereas evolution and processes of creating galaxies and stars are an ongoing operation, which to the untrained eye is nearly imperceptible, science has enabled us to get a greater understanding of the processes.

Galaxy Formation In a seemingly lifeless cloud of gas and small objects, a galaxy is about to be born. That seemingly empty, cold mass of gaseous clouds holds the essential ingredients of a future galaxy. This almost empty stagnant environment contains all the matter and energy to create a huge galaxy containing hundreds of thousands of powerful stars and planets.

There are several forces at work in huge primordial gas clouds. Gravity and centrifugal force being the most importent.

The Sky Is Filled With Galaxies

With centrifugal force from the original Big Bang and moving at a half million miles per hour, this large area of gasses is spinning in unison. There are several theories on how this primordial gas comes together to form a galaxy. The second theory claims galaxies were formed by several smaller clouds of gas merging into one.

The an in depth look at the states and galaxies theory states that galaxies were formed by numerous small gas clouds merging into one. The centrifugal force of the spinning gas cloud along with the gravitational pull within the clouds work together to give a galaxy its shape. All galaxies began with an elliptical shape, which is mostly a result of the centrifugal force of the spinning gas cloud.

Like pizza dough being spun into the air the gas cloud flattens to a thin disk shape. Many Galaxies evolve into much more complex shapes. There are four types of galaxies. These four types or groupes are devided by their shape. This classification system was developed by the astronomer Hubble and is named the Hubble classification.

The four types of galaxies are spiral, barred spiral, elliptical, and irregular galaxies. A typical spiral galaxy contains about one hundred billion stars and is approximately one hundred thousand light years across. They are characterized as well as classified by the thickness of the central bulge.

Our Milky Way galaxy is an example of such a spiral galaxy. A barred spiral galaxy is charaterized by a destinct bar running through its nucleus. Like the spiral galaxy, the barred spiral galaxy has a central bulge containing the majority of mass in the galaxy. This process is simmilar to spinning a lopsided beach ball into the air. The unbalanced ball wobles as it spins.

If the ball was viscus the denser area would begin to pull away forming a spiral arm. An elliptical galaxy is of-course elliptical in shape. Elliptical galaxies are almost void of interstelar gas and dust. Thislack of gas and dust inhibits star formation. Irregular galaxies can come in many different shapes. They are put in this group because they don't fit into any of Hubble's other classifications. Irregular galaxies like the three other types are further broken down into more specific groups based on other characteristics.

Galaxies are not the largest units in the universe. Most galaxies are related to others in large galaxy clusters. A large galaxy cluster may contain thousands of galaxies. A small or poor galaxy cluster may contain only a few dozen galaxies. There are two types of galaxy clusters a regular cluster and an irregular cluster. An an in depth look at the states and galaxies cluster has no destinct shape and has galaxies equally despersed throughout. Our galaxy, the Milky Way, is a member of a poor irregular galaxy.

A galaxies shape, size, and mass rarely change after its formation. One way formed galaxies do change is through galaxy collision.

  • Many Galaxies evolve into much more complex shapes;
  • Similar to the previous animation, but this time showing various projections of the likely 3D shape of low spin galaxies in our study.

Since galaxies are spinning through the universe they sometimes run into each other. These collisions can throw stars out of galaxies or cause one galaxy to canabolize matter from another, aiding in its growth.

These collisions must truely be catastrophic events. Galaxy Formation Conclusion Galaxies come in many shapes and sizes but they all form under the same processes.

The two most importent forces are centrifugal force and gravity. These forces work together on interstellar gas and dust to form all galaxies. It is this same ingrediants and forces that come together to form the stars and planets that make up galaxies.

Most of the matter in a mature galaxy is contained in these stars. A star is born through intertwining gravitational forces as cold, dense clouds of gas are being compressed.

Two main ways in which a star can be born, are through the result of compression of the remnants of a super nova or from the pulling together of interstellar dust and clouds of a nebula.

The extra dimension

As an aging star begins to deteriorate and die, one of the possibilities is that the star reaches a critical mass where as the outer layers are too heavy, and the core can no longer support its immense weight. When this happens the star collapses in on itself until it cannot collapse any further. The rapid implosion of matter comes to a halt when it cannot fall any further, and that energy is transformed into a massive shock wave that bounces back away from the core in all directions taking all of the matter with it in a monstrous explosion called a supernova.

From the remnants of this violent death comes the rebirth of new stars resulting from the element rich explosion. These masses of interstellar dust and glowing gas contain essential elements for the composition of stars.

Many nebulae have young stars forming at the same time. The intense radiation given off by the new stars fueling themselves causes the surrounding gases to glow which in turn gives the nebulae its ethereal luster.

The solar nebulae is comprised of essential elements for the production of new stars. As the cloud of gas is pulled together, it becomes more dense and opaque. Once this stage is attained, the effect that gravity has on the mass begins to accelerate. This intense squeezing together of a cloud of dust and gas is what begins star formation. As the gas cloud condenses it gets a vigorous rotation. This rotation causes an in depth look at the states and galaxies dust and gaseous particles to be slung away by centrifugal force.

Some of these particles may eventually come together to form planets, or secondary stars. If the cloud has enough mass, that is the cloud has the critical mass to generate enough heat in its core to begin the process of hydrogen fusion, process of having enough mass and pressure to fuse two hydrogen atoms together. The process of hudrogen fusion is were four hydrogen atoms are squezed together till they combine to form one helium atom. The snow balling of this reaction results in the birth of a star.

These failed stars are in essence hydrogen-enriched planet. It is both an ancient and continuous process. This process gives perpetual birth, life, death, and rebirth to the universe. It is amazing that this seemingly random and sometimes violent formation of heavenly bodies has worked so harmoniously to create the universe we know today. The formation of the galaxies and stars play an integral part in our daily life.

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It is the sun that gives life to the Earth and a habitable environment for its inhabitants. It will be the sun and the continual processes of the universe that will eventually claim the Earth and all life on it, although the evolution of our galaxy will continue uninterrupted as it has over the past billions of years.

Glossary of terms angular velocity- The velocity of an object due to the angle at which it lies, as compared to a larger source of gravity. Big Bang- Theory of how our universe began.

Cluster of glowing matter pulled together by gravity. Can produce the stituation where new stars can form.


Sources Kaufman, William J. Freeman and Company, 1979. Freeman and Company, 1994. A Short History of the Universe. Scientific America Library, 1994. The Birth of the Universe: The Big Bang and After.