I could be wrong, but it was my impression while watching the documentary Particle Fever (2013) 1 that most film viewers will not have a high enough level of science literacy to be able to appreciate the significance of the events it depicts. My intent in writing this essay is to provide a brief sketch of some of the historical background in order to make the significance of what is depicted in the documentary more apparent.
Working as a scientist during the second half of the 20th Century gave me a front row seat for observing some monumental, and not always fully appreciated, revisions to scientific theories regarding fundamental properties of the universe in which we live.2
Our conceptions of the size of the universe underwent a seismic shift. Up until early in the 20th Century, scientists thought that our galaxy, The Milky Way, was the entire universe. Then it was discovered, first that the Milky Way is part of a group of about 40 galaxies that make up a structure called the Local Group. Then, that this Local Group is only one of at least 100 other similar groups bound gravitationally into what is called the Virgo Supercluster. And most recently that Virgo is only 1 of about 10 million superclusters in our Universe. And, some current theories of physics propose that our universe might very well be only one of many that collectively form a larger Multiverse.
Another major revision has to do with how science characterizes the history of the universe. Current scientific theories are similar to many religious theologies in that they describe a creation story for the universe that has a beginning (big bang) and an ultimate fate (big freeze), but this is contrary to most of scientific history. Newton saw the universe as being eternal in space and time with universal laws that applied to all parts all the time. Similarly, up until the 1920s most scientists believed that the world is eternal, infinite, and uncaused, in need neither of an act of creation nor a creation story. When Einstein published his general theory of relativity in 1915, he realized that it did not describe a stable universe, but he was so troubled by this implication that he added a cosmological constant to his theory that had only one purpose, to make the universe stable. He later considered this to have been one of the biggest blunders in his scientific career.
Over time, theoretical physicists examining the implications of Einstein’s general theory of relativity realized that the theory actually describes an expanding universe. But if the universe is expanding, expanding from what? Mathematicians discovered that the equations Einstein used to describe the universe can be run backward as well as forward in time to simulate what the universe looked like in the past and what it will look like in the future. When run backward the universe shrinks to an infinitesimally small point. Modern science now posits that our universe was created by an explosive expansion from that single point, a big bang, that happened about 14 billion years ago.
Several details about the big bang theory have undergone revisions over the decades since it was first proposed. One of the unresolved issues until very recently involved the ultimate fate of the universe. Depending on the values of certain parameters in the theory’s equations, the universe could be expected to: 1) expand only up until a certain point, and then (due to gravity) begin to contract again, ending in a big crunch; 2) arrive at a steady state and then stay in this state forever; or 3) continue to expand forever. It was only in the 1990s that scientists obtained enough empirical evidence to specify these parameters. We now know that our universe is expanding so fast that there is not enough gravitational force to stop it, so its fate appears to be that it will continue to expand and cool into cold utter darkness, the big freeze.
There have also been revisions to the way science characterizes the nature of what was present at the moment of the big bang. Originally, it was assumed that the stuff that is present in our current universe had just been compressed to a very small size, a single point. However, more recent interpretations of the big bang allow the current universe to have emerged from bubbles of quantum foam, stuff that exists outside of time and space and thus are “no material thing”, or stated more colloquially, out of nothing. The transitions from the original idea of a stable, unchanging universe; to that of a universe that has always contained the same stuff, but is changing in size as that stuff expands starting with the big bang; to the current notion that our universe might have formed out of “nothing”, came gradually as scientists and mathematicians explored the implications of the theories of relativity and of quantum physics.
Immediately after the big bang, the universe existed in a state of extremely high energy. Only subatomic particles populated the universe because they could not yet fuse to form atoms. The forces that hold protons and neutrons together in the nucleus (strong force) and that hold electrons in orbits around the nucleus (weak force) were not strong enough to keep atoms from blowing apart under these high energy conditions, as happens in a nuclear explosion. However, as the universe continued to expand, consequently it also started to cool down, and some of the high energy particles started to coalesce forming persisting larger particles such as atoms, and eventually the large scale structures that make up our current universe such as galaxies composed of stars and planets.
The Holy Grail in physics is to construct a unified Theory of Everything that is capable of specifying a causal chain of events that lead from the high energy particles present at the time of the big bang to the structure of our current universe (as well as predict what will happen to that universe in the future). No such theory exists, but the one that comes the closest to date is referred to as The Standard Model. It posits that our universe is constructed out of 61 elementary particles with names such as Quarks, Leptons, and Bosons, and it specifies how these elementary particles combined to form other particles as the universe cooled.
The Standard Model is a work in progress. Scientists know that it is still incomplete and wrong in some of its current details. Nevertheless, the amount of empirical evidence that has accrued in support of it is rather remarkable and comes from divergent sources. Measurements of properties of entire galaxies using telescopes have confirmed specific predictions such as that the conditions present shortly after the big bang should have produced a universe containing seven protons for every neutron.
Other evidence has come from experiments looking at properties of matter at the opposite end of the size spectrum, subatomic particles. Experiments carried out with particle accelerators have been used to simulate the high energy conditions that existed shortly after the big bang. These experiments have confirmed many predictions of The Standard Model.
One specific prediction involves the Higgs Bosun, a particle that has to exist for The Standard Model to be correct, in fact it is so critical to the theory that it has sometimes been called (tongue firmly in cheek) the God Particle. This is because without the Higgs Boson being present, The Standard Model can create a universe full of energy, but not with any structures that have mass; No stars or planets or rocks or trees or us humans.
Scientist did not have the technical capability to create high enough energies to look for the existence of the Higgs Boson until the Large Hadron Collider in Switzerland was completed in 2008. Experiments carried out at this facility finally provided convincing evidence for the existence of the Higgs Boson in 2012, a monumental discovery in the history of science that led to The Nobel Prize in Physics being awarded to François Englert and Peter W. Higgs, the boson’s namesake. The film Particle Fever documents activities of some of the scientists from around the world as they worked on this project. One of the most moving scenes in the film for me was a shot from across the room as Peter Higgs quietly pulled a handkerchief from his pocket and appeared to be dabbing a few tears from his eyes after the official announcement of the discovery was made.
The film Particle Fever seemed to me to pretty much gloss over this monumental discovery and instead chose to focus mostly on the fact that two camps of scientists working from different theoretical perspectives, called Supersymmetry and Multiverse, had different expectations about some specific properties of the Higgs Boson that was discovered. Apparently, someone convinced the film’s producers that the only way to “sell” a documentary about science is to force it into a “competing theories” paradigm. In my opinion, this issue deserved no more than a footnote which is the way I will deal with it here 3, and wish the filmmakers had done the same. The bottom line for science is that there is still work to be done. That is the way science works. Theories generate experiments, and results of experiments either confirm predictions made by the theory or force modifications to it. And there is no reason to think this iterative process will end any time soon.
1. The theme for our discussion films this month is The Universe in Three Acts, and each of our three films illustrate different approaches to trying to understand some of the fundamental truths about the universe in which we live. In this essay I discuss an approach taken by the scientists depicted in the documentary, Particle Fever (2013): empirical science. In separate commentaries, I discuss a mathematical approach to discovering fundamental truths depicted in the fictional film Pi (1998), and the quasi-religious approach of our third discussion film, Le Quattro Volte (2010).
2. I have drawn on many sources for the facts presented in this essay. I will not document my sources here — It is possible to find all of these facts pretty easily nowdays by doing a “google search” on the internet. However, I do want to acknowledge a remarkable small book that provides several of the examples I use here:
Christopher Potter, You Are Here: A Portable History of the Universe, Harper, 2009
3. The controversy has to do with how one accounts for the fact that the Higgs-like-Boson-Particle that was discovered has a mass considerably different than predicted by The Standard Model. That means The Standard Model will need to be modified in some way to account for this unexpected finding. Scientists approaching this problem from the Supersymmetry theoretical perspective thought they might have way to solve this problem, but only if the Higgs Particle appeared at an energy level near 115 GeV. Scientists from the Multiverse perspective had a different potential solution that might work if the Higgs Partcle appeared at an energy near 140 GeV. The actual results fell pretty much right in the middle between these two values at 125 GeV.