The Big Bang Controversy



The Big Bang Controversy

Introduction

The big bang theory is the presently generally accepted model of cosmology that describes the evolution of the universe as starting in an explosion 13.7 billion years ago from an extremely small and dense state. Initially the entire cosmos was compacted into a size smaller than an atom. Since the beginning, the time point of the big bang, the universe has been expanding and cooling. The theory describes the universe from a fraction of a second after the explosion and explains the origin of galaxies and stars. No current theory explains the universe before the big bang.

The Very Early Universe

One principle governing the origin of the universe is the inverse relationship between the temperature of the universe and its size and age. Temperature is a measure of heat, and therefore the internal energy associated with a substance. A high temperature is associated with a lot of heat, or a large quantity of energy. At the time point of the big bang, the temperature of the universe was infinitely hot, and since then the universe has been cooling (Singh, 2004).

The furthest back modern physics can adequately attempt to explain is to about 10-43 second after the big bang. At this time, the size of the universe was around 10-35 meter and its temperature was some 1032 kelvins. Particle physics models predict that at this temperature, the four natural forces (the gravitational, electromagnetic, strong nuclear, and weak nuclear forces) were unified into a single superforce. As the universe expanded and cooled, the gravitational force became distinct from the superforce, marking the beginning of the grand unified era, in which the other three forces were still unified. The universe was still extremely dense, and the particles continually collided with one another.

The universe continued to expand and the temperature continued to decrease until it reached a critical point, when the universe was about 10-35 second old and the temperature was around 1027 kelvins, a time referred to as the inflationary phase. During inflation, the expansion rate of the universe accelerated rapidly. Inflation ended at 10-33 second, when expansion began decelerating and the universe continued cooling. Then the strong nuclear force became distinct from the grand unified force, leaving the electromagnetic and weak nuclear forces still unified as the electroweak force. That era ended when the universe was 10-10 second old, and the weak force split from the electromagnetic force when the temperature was 1015 kelvins, giving the four distinct fundamental forces that govern the natural world.

The next era was the quark era. Quarks are among the elementary particles that compose all matter and interact with one another via the strong nuclear force that holds atomic nuclei together. At this temperature, however, the strong nuclear force was too weak, and gluons, the exchange particles for the strong force, could not hold quarks together. When the temperature cooled to 1012 kelvins, quarks began to combine with other quarks, ending the quark era. By the time the universe was 10-4 second ...