Dr. Alan Guth: An Alternative of the Big Bang Theory

I researched Dr. Alan Guth, an American physicist and cosmologist. He is currently the Victor Weisskopf Professor of Physics at the Massachusetts Institute of Technology. He graduated from MIT in 1968 with a Bachelor degree in physics and stayed in the same institute to receive a master's and a doctorate, both of which in physics. As a junior particle physicist, Guth developed the idea of cosmic inflation in 1979 at Cornell and gave his first seminar on the subject in January 1980. Moving on to Stanford University Guth formally proposed the idea of cosmic inflation in 1981, the idea that the nascent universe passed through a phase of exponential expansion that was driven by a positive vacuum energy density (negative vacuum pressure). The theory of cosmic inflation is proven to be very compelling by the WMAP mission in 2006.

Most of his research has centered on the application of theoretical particle physics to the early universe: what can particle physics tell us about the history of the universe, and what can cosmology tell us about the fundamental laws of nature? In 1981 he proposed that many features of our universe, including how it came to be so uniform and why it began so close to the critical density, can be explained by a new cosmological model which he called inflation. Inflation is a modification of the conventional big bang theory, proposing that the expansion of the universe was propelled by a repulsive gravitational force generated by an exotic form of matter. Although Guth's initial proposal was flawed (as he pointed out in his original paper), the flaw was soon overcome by the invention of "new inflation" by Andrei Linde in the Soviet Union and independently by Andreas Albrecht and Paul Steinhardt in the US. 

One of the intriguing consequences of his finding in inflation is that quantum fluctuations in the early universe can be stretched to astronomical proportions, providing the seeds for the large scale structure of the universe. The predicted spectrum of these fluctuations was calculated by Guth and others in 1982. These fluctuations can be seen today as ripples in the cosmic background radiation, but the amplitude of these faint ripples is only about one part in 100,000. Nonetheless, these ripples were detected by the COBE satellite in 1992, and they have now been measured to much higher precision by the WMAP satellite and other experiments. Another intriguing feature of inflation is that almost all versions of inflation are eternal—once inflation starts, it never stops completely. Inflation has ended in our part of the universe, but very far away one expects that inflation is continuing, and will continue forever. Is it possible, then, that inflation is also eternal into the past? Recently Guth has worked with Alex Vilenkin (Tufts) and Arvind Borde (Southampton College) to show that the inflating region of spacetime must have a past boundary. 

Working with Dr. Edward Farhi and others, Guth is now exploring the question of whether it is in principle possible to ignite inflation in a hypothetical laboratory, thereby creating a new universe. They showed that it cannot be done classically, but with quantum tunneling it might be theoretically possible. Don’t worry, the new universe, if it can be created, would not endanger our own universe; instead it would slip through a wormhole and rapidly disconnect completely.

Work Cited

The Inflationary Universe: The Quest for a New Theory of Cosmic Origins, Perseus Publishing, March 1998.

"Alan Guth: A Golden Age of Cosmology", December 4, 2001.