Particle Physics and Cosmology: The Interface Book

The book's stated purpose is to describe "the origin, structure, and fate of the universe." Boiled down, the book outlines what happens post Big Bang. In the immediate aftermath of the Big Bang event (fractions of the initial second), the forces (gravity, strong, weak and electro-magnetic) that govern the interactions of matter separated out as temperature cooled, allowing the components of matter to form (quarks [elementary particles], protons and neutrons [nucleus], nucleus and electrons [atoms]). Then, over thousands and hundreds of thousands of years, these components of matter and energy turned into stars and planetary bodies, galaxies and clusters of galaxies and super clusters of galaxies, all lined out, the author says, like "pearls on a string," with vast empty spaces in between. At each of these transformation points, in what Trefil calls a "freezing effect," temperatures cooled to a critical point that allowed this conversion of energy to new forms of matter from prior forms.

This is where we are at today. Trefil then rolls out the possible cosmic futures in three fairly well-known scenarios. First, there's the closed universe where gravity pulls all of this back to a center point called the "Big Crunch" and, second, there's the open universe which means there's an infinite expansion of the universe. And, third, there's a flat universe where the gravitational pull slows the outermost objects but is not of sufficient strength for the universe to reverse this process as in the Big Crunch scenario. The author leans heavily toward the flat universe and in many ways the book provides his arguments for why he believes this scenarios makes the most sense. Many of his arguments I found to be difficult to follow.

In the author's view, the "phase change" where the strong force that binds nuclei elements freezes out (at 10-35 seconds into the Big Bang) created "inflation,"which was the rapid expansion of the then universe. It is inflation, he writes, that "leads to the prediction that the universe must be flat." Though right off I can't say I understand this, I thought his description of inflation was excellent. It is "similar in many ways to the freeing of water" that expands when it changes into ice." "What is surprising," he adds, "is the sheer magnitude of the expansion. The size of the universe is increased by a factor of no less than 10 to the 50th power! This number is so huge that it is virtually without meaning to most people, including the author. Let me put it this way: If your height suddenly increased by a factor as large as this, you would stretch from one end of the universe to the other, with room to spare....At 10 minus 35 seconds, the universe went from something with a radius of curvature much smaller than the smallest elementary particle to something about the size of a grapefruit." It's not only magnitude but the speed of the explosion, which far exceeds the speed of light. Here, the author says that Einstein's law regarding the speed of light applies to "the movement of objects in space, but not to the movement of space itself." "Strictures against faster-than-light travel," he says, "apply only to motion within space, not to the motion of space."

Trefil counters the way that entropy is usually described (the movement from an organized whole to homogeneous simplicity via heat dissipation/death) when he states that the universe remains "complex out to the largest scales." He seems to be saying that at the pre-big bang moment, energy/matter exists as elemental simplicity, an undifferentiated state of oneness where energy and the pre-components of matter are merged. This is where the holy grail of physics lies. It's a Theory of Everything, a "super symmetry" where "one sort of particle...that would account for both structure and force" is to be found. Flowing from a state of undifferentiated Oneness is the differentiation into the many (the various forms of micro to macro matter) that eventually result in the collection of galaxies that progressively move outward into expanding space (expanding via some sort of dark energy/radiation?) that would, thereby, maintain differentiated structures in perpetuity in his flat universe scenario.

Trefil opens his book with a reference to a Greek philosopher who wondered what would happen if one walked to the edge of the universe and tossed a spear. As it would land beyond the point at which one was said to be at the edge, the conclusion must be that "the universe cannot have an edge." Later, Trefil quotes, approvingly, Nicholas of Cusa who wrote that "'the universe has its center everywhere and its circumference nowhere.'" I can't say that I understood these references. The first one, cleverly stated as it was, still begs the question as to whether anything, in a Big Bang scenario, lies beyond the leading, expanding edge of the universe (i.e., is space in the sense of distance between bodies and events, as some have written, itself created from the Big Bang). And, if there was a Big Bang event, presumably, it started from a center point, not "everywhere" and if it has a leading, "edge" (?) emanating from an expanding center point, how could it be said that it has no circumference? Is not the Cosmos round?