The Big Bang

Due Date:

21 March 2014

The Big Bang

Jacob Bowerman

When astronomers are talking about the birth and evolution of the universe, they are referring to the development of space time, with space itself expanding as time moves forward from the creation of the universe, otherwise known as the Big Bang. According to the Big Bang theory, the universe began by expanding from a very small volume with incredibly high density and temperature. With the occurring of the Big Bang, the fabric of space itself started expanding, matter simply rode along the stretching space. The Big Bang occurred 14 billion years ago, that's when time, space and matter all began. In a fraction of a second, the universe grew from being the size of a single atom to becoming bigger than a galaxy. That wasn't the end of its expansion though, it kept its expansion at a fantastic rate, even today it is still expanding. As the universe expanded and cooled down, energy changed into particles of matter and antimatter. Over the next three minutes, the temperature dropped below 1 billion degrees Celsius, this mean that it was then cool enough for the protons and neutrons to come together, then forming hydrogen and helium nuclei. After 300,000 years, the universe cooled to about 3,000 degrees. Atomic nuclei could then finally capture electrons to form atoms. The universe then filled with clouds of hydrogen and helium gas.

Upon the early 1900's, most people had assumed that the universe was fixed in size. A range of new possibilities was then opened up in 1915, when Albert Einstein devised his general relativity theory that describes the nature of space, time and gravity. In 1917, an astronomer named Willem De Sitter applied Einstein's theory to the entire universe, and t...

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...anding universe, we imagined a dense, hot beginning of our universe 13.7 billion years ago in the past. After the universe then began to expand, it cooled, going from extremely small to the size and temperature of our current universe. During the middle of this century, we discovered that nuclear reactions in this hot early universe precisely account for the previously mysterious abundance of helium and deuterium. However, we detected a faint glow after the Big Bang occurred 13.7 billion years ago. The theory in which the universe began with the Big Bang is one of the most profound discovery humans have ever made. The Big Bang theory is however a global description of the beginning of time, matter and space. Today, physicists have consistent theories about the history of the universe down to only a trillionth of a second after the universe's birth or even earlier.