The Theory of the Big Bang has a misleading title. It isn’t that surprising, as many popular scientific concepts have names born from casual conversations, editing of a paper, or happenstance. For example, the Higgs particle is often referred to as as the “God Particle”, when in actuality it was being called the “god damned particle” colloquially my scientists because it is so hard to find, and an editor of a magazine cleaned the term up for print. Big bang got its rather explosive name when the eminent astronomer Fred Hoyle used the term sarcastically on a radio program. The name stuck.
In reality standard big bang theory simply describes a universe getting smaller and smaller as one moves backward in time, a description which explains many things in our universe and is backed my quite a bit of observational evidence. However, the standard big bang theory doesn’t say a whole lot about the actual start of the universe, or really anything about 1 second after the assumed start time. Because the universe would have been an extremely dense, hot soup of fundamental particles at this time, big bang theory has had a difficult time explaining what was occurring. In the past this indirectly lead to a couple of subtle problems in our observations of what a standard-model big bang universe should look like. I won’t dive into the various problems, as they are described in the book I am about to review!
The Inflationary Universe by Alan Guth explains the theory of inflation, an add-on to the standard big-bang theory. Inflation was first developed by Guth in the late 70s and early 80s. Guth, with subsequent work by several physicists from around the world, established a mathematical model which helped solve several important problems in cosmology and the big bang theory. In the book Guth takes the reader through the events that lead to his discovery, and subsequent refinement, of inflationary theory.
I found the book, and Guth, fascinating for a few reasons. First, there is the history of the discovery. The way in which Guth found inflation is a familiar story we find in science of someone working on one problem and stumbling onto the solution for another. Guth had the insight to see a big picture in a somewhat obscure problem on which he was working, which lead to describing the earliest points in time we can account for with modern science.
Second, Guth apparently kept a great diary, and refers to it occasionally. The detail of the story is amazing, relating personal connections with family, friends, and fellow scientists. Guth isn’t afraid to share what he was feeling at the time, and this paints a terrific picture of a scientists making a discovery.
And last but not least, there is the actual science. The insight that Higgs fields, the fields that provide mass for the universe provided us with inflation in the very early universe is interesting to say the least. (Note: Higgs fields are still theoretical today, although they fit into the standard model which is well described and supported with evidence. In fact some would say that the Higgs field is required to exist for the standard model to continue to work. The search for the Higgs particle is a major effort underway today.)
Inflation, painted with broad brush strokes, is the concept that the universe expanded very rapidly in a very short period of time due to the cooling of the Higgs fields present. As the fields tried to reach a lower state of energy, as does everything in our universe (read: entropy), they created a negative pressure inside their field. Negative pressure created negative gravitational energy, so much so that space itself was flung out in all direction rapidly as the fields, permeating all of existence, cooled. This rapid expansion, through careful mathematical studies, solves several problems. To boil it down, much of the so called fine tuning required for the universe evaporates when inflation is taken into account.
I found the book to be a very interesting read. It isn’t always the case that a brilliant scientist is also a good writer that can convey their concepts to the general public, but this is exactly the case with Alan Guth and The Inflationary Universe.