Genesis: The origin of the universe

National Forum, Winter 1996 by Wersinger, J-M

The other two questions are simple: what produced the bang and how did the universe appear?

Cosmic Inflation

As the moment of creation is approached, conditions of temperature and density become so extreme that laboratory physics no longer applies. The only avenue left to probe the first fractions of a second in the universe's existence is mathematical modeling relying on fundamental principles of physics and on arguments of simplicity and aesthetics -- a route that has been extremely successful in theoretical physics, starting with the discovery of the theory of Relativity by Einstein. A group of east coast physicists and cosmologists are actively engaged in theoretical modeling of the early universe. One of them is Alan Guth of MI an elementary particle physicist who, in the early 1980s, developed a very interesting model for the behavior of the universe when it was a mere 10 sup -35 seconds old, called the inflationary universe. This model resolves our two paradoxes and provides a mechanism for the explosion.

The universe is organized by four basic forces that give it structure from the microscopic scale to the cosmic scale. The weakest force is gravity, which gives structure to the universe on the cosmic scale and whose influence, or range, extends over cosmic distances. It builds planets, stars, and galaxies. The electromagnetic force, which is much stronger than gravity, also has an infinite range. It creates the atomic structure and produces the four states of matter: gas, liquid, solid, and plasma. The strong nuclear force has a very short range and is the agent that builds nuclei, providing us with the variety of chemical elements and their isotopes. It is the force that powers the hydrogen bomb and makes the stars shine. There is another nuclear force, called the weak force, with a very short range, but which has less of an organizational function than the other three. Without the existence of these forces our universe would be a structureless soup, without life, planets, stars, and galaxies, and without light.

The electromagnetic force is actually made of two forces, the electric force and the magnetic force, unified in a single theory last century by James Maxwell, a British physicist. Unifying all known forces into a single theory is the holy grail of theoretical physics. Einstein spent over half of his professional life in an unsuccessful quest for a unified theory of the basic forces. In the late 1960s and early 1970s, the electromagnetic and the weak nuclear forces were unified into a single electroweak force by Sheldon Glashow, Steven Weinberg, and Abdus Salam, who were awarded the Nobel prize for this work in 1979. Since then, physicists have tried to incorporate the strong nuclear force into the theory. Theorists believe that there is a unique theoretical framework, a Grand Unified Theory (GUT), that incorporates both the electroweak and the strong nuclear force into a superforce. The prevailing idea is that when the universe's temperature was above 10 sup 28 K all forces except gravity were indistinguishable and that the distinct forces we now observe are merely low-temperature manifestations of the superforce.