Origin of the Universe

[Lauren Howe]

How was the universe created?

There are two theories that explain the existence of the universe; the Big Bang Theory and the Steady State Theory.

The Big Bang Theory suggests that about 12-15 billion years ago all matter and energy exploded and expanded from an original point of nothing. This was when both time and space were created.

The Steady State Theory states that the universe is expanding and has no beginning and no end. It exists without changing with time.

What is the approximate age of the universe?

It is predicted that the universe was shaped at 10 to the -6 seconds after the big bang (10 to the -35 seconds). The basic elements began to form approximately 3 seconds after the big bang. All of this happened about 12-15 billion years ago and NASA studies have now narrowed that number down to 13.7 billion years.

The Big Bang Theory

What is the big bang theory?

The big bang theory started off that all matter was compressed into a space about the same size as our sun. Relating to what I said before this all started about 12-15 billion years ago. There are two theories to describe the big bang. The first is that there used to be a hot fireball (the size of our sun) that held all the matter of the universe that eventually expanded due to all the pressure. Suddenly and instantly, matter and energy was distributed throughout the universe, although it was less like the explosion of a bomb rather and more like the explosion of space within itself. All that compressed matter did not contain miniature galaxies and planets that grew but more like the foundations to create them.The second, more recent theory was that the universe developed out of nothing at all and expansion started time and space. The very first man to suggest the big bang theory was Georges Lemaitre. Another man, Edwin Hubble (1920’s), discovered that galaxies were in fact moving farther away from us in every direction and the farther they are, the faster they recede. He came to a conclusion that our earth was expanding and cooling and that this all originated form a single point. Another piece of evidence (the strongest evidence) for the big bang is what is called Cosmic Microwave Background discovered by Arno Panzias and Robert Wilson (1960’s). They discovered that our universe was once as a very hot fireball and also discovered that the universe is approximately 3 degrees above 0 (CMB) or also called the ‘echo’ of the big bang. The most recent piece of evidence is from NASAs COBE satellite. It detected cosmic microwaves coming far from the universe and it also discovered that the universe was still expanding. It had also detected small variations of temperature which proved the possible theory of the universe cooling.
Scientists now believe that our universe is not only expanding, but it is expanding from a certain centre (big bang). Since it all started off with one point, technically, the point has expanded and not the universe from that point. Point=Universe. Here is an example:

Who supported the big bang theory?

George Gamow mainly supported and developed the big bang theory with his student, Ralph Alpher. They explained the reactions that occurred during the big bang. Later on Fred Hoyle explain what they missed, the presence of elements heaver than helium.

Why is the Big Bang generally more supported?

The big bang theory is generally more supported than the steady state theory for 3 main reasons; Big Bang Nucleosynthesis, CMB and the Hubble Expansion.

The Steady State Theory (Static Theory)

What is the steady state theory?

Contrary to the big bang theory, the steady state theory states that the universe is and always will be the same size. There is not much evidence that can support this theory, thus little astronomers and people believe it. That is, all except for one, Fred Hoyle. Fred Hoyle is a British astronomer who strongly supports this theory. This theory was originally supported and created by two astronomers in 1948. They were Hermann Bondi (Austrian-British) and Thomas Gold (Austrian-American).

Explosion & Expansion: What’s the difference?

Here are definitions of both:
Explosion: “a sudden increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases.” (Wikipedia)
Expansion: “the act of increasing (something) in size or volume or quantity or scope” (Dictionary.com)

The main difference (which is not clearly stated in these definitions) is that explosions happen suddenly and cause a shock wave. Expansion on the other hand, happened over a prolonged period of time.

Expansion, temperature and formation of matter: what is their relationship in the early stages of the ‘big bang’?

In the early stages of the ‘big bang’, the universe expanded and as the universe expands it cools (temperature drops). As the universe began to get cooler, all the energy released began to form matter. They all relate to one another. The universe expanded, cooled then formed matter.

How to the latter stages of the ‘big bang’ lead to a state where the whole universe was similar to the early stages of a star’s life?

The latter stages of the big bang were very similar to the early stages of the life of a star. The big bang originated from a large, hot ball of energy that expanded quite quickly. This eventually formed all of our stars and planets today. How? When the universe was expanding and cooling there was hydrogen and helium that would collect into a clump together due to the force of gravity. When the universe continued to expand, the clump’s pieces separated throughout the universe. Stars are made up of hydrogen and helium so what do you think happened? The pieces from the clump that were once scattered are not our stars.