Amir D. Aczel writes often about physics and cosmology. His book about the discovery of the Higgs boson, Present at the Creation: Discovering the Higgs Boson, is published in paperback by Broadway Books in November 2012.
If somebody told you that there are angels floating in space, observing our world and forming their impressions of our everyday reality, you would think that this person is nuts—a religious fanatic with an active imagination, and certainly not a scientist. Scientists, as we all know, are rational beings who believe only in what nature reveals to us through experimentation and observation, coupled with theory that is never divorced from the physical measurements they make. The link between the two remains tightly regulated through the strict rules of the scientific method.
So how do you explain the bizarre fact that, for about five years now, some of the world’s most prominent physicists have been describing a scenario—which they seem to truly believe may be real—in which, instead of the Biblical angels, space is permeated by disembodied brains?
These compact, conscious observers, called “Boltzmann brains,” cruise the vastness of intergalactic space, and beyond it, to the infinite “multiverse” that some scientists believe exists outside the reaches of the universe we observe through our telescopes and satellites. Their consciousness makes the Boltzmann brains recreate our reality. They imagine life such as the one you and I believe we are experiencing here on Earth, to the point that these brains in space may think that they are living on a planet like ours, that they may even be us. Some recent physics papers and commentaries have even explored the possible limits on the number of Boltzmann brains in the universe as compared with “real” brains, in an effort to estimate the probability that we are real rather than Boltzmann entities.
Amir D. Aczel (amirdaczel.com) writes about mathematics and physics and has published 18 books, numerous newspaper and magazine articles, as well as professional research papers.
A Higgs candidate event from the ATLAS detector of the LHC.
Courtesy of CERN
What made me fall in love with theoretical physics many years ago (in 1972, when I first met Werner Heisenberg) was its stunningly powerful relationship—far beyond any reasonable expectation—with pure mathematics. Many great minds have pondered this mysteriously deep connection between something as abstract as mathematics, based on theorems and proofs that seem to have little to do with anything “real,” and the physical universe around us. In addition to Heisenberg, who brilliantly applied abstract matrix theory to quantum physics, Roger Penrose has explored the deep relation between the two fields—and also, to a degree, between them and the human mind—in his book The Road to Reality.
And in 1960, the renowned quantum physicist and Nobel Laureate Eugene Wigner of Princeton wrote a fascinating article that tried to address the mysterious nature of this surprising relationship. Wigner marveled at the sheer mystery of why mathematics works so well in situations where there seems to be no obvious reason why it does. And yet, it works.
Amir D. Aczel has been closely associated with CERN and particle physics for a number of years and often consults on statistical issues relating to physics. He is also the author of 18 popular books on mathematics and science, and has been awarded both Guggenheim Foundation and Sloan Foundation fellowships. Many thanks to Steven Weinberg of the University of Texas at Austin and to Barton Zwiebach of MIT for their helpful comments.
Readers of this blog have probably heard the standard fare about how the Higgs boson “gives mass” to everything in the universe, probably with some kind of analogy, like the one about a famous person walking through a crowded room, pulled every which way by admiring crowds, and that these connections “make the person massive“—as the Higgs field does with particles. Now that we finally seemed to have pinned down the elusive particle, I want to explain where the Higgs came from and what it does. While our understanding of the particle comes from some complicated math, the formulas actually tell a fascinating story, which I’ll recount in this post. All you need to keep in mind is that in the modern understanding of physics, categories aren’t as starkly separate as you might think: particles can be represented as waves or fields, and a force can also be viewed as a particle or a field.
So, a fraction of a second after the Big Bang, the universe had four kinds of “photons” floating around—the usual photon of light, and three other massless particles that “look” and act just like the photon. We label them: W+, W-, and Z. They are bosons, meaning carriers of force, as is the usual photon.
At the Big Bang, the universe also had one, unified, mighty force called the Superforce ruling it. But a tiny fraction of a second before the era I am talking about, the Superforce began to break down, successively “shedding off” part of itself to make the force of gravity, and another part of itself to make the strong nuclear force, which later would be active inside the nuclei of all matter, holding quarks inside protons and neutrons once these composite particles came into being. The two forces, gravity and the strong force—important as they are—do not enter our main story today.
The remnant we have of the Superforce at the time we are talking about, a tiny fraction of a second after the Big Bang, has three forces of nature held together inside it: electricity, magnetism, and something called the weak nuclear force, which later would be responsible for beta decay, a form of radioactivity. You may remember from a physics course that “electromagnetism” unifies electricity and magnetism, as Maxwell taught us over a century ago. But, during the era I am talking about, there are really three linked forces: electro-magnetic-weak; all three are held together as the electroweak force that remained from the Superforce after it had shed off gravity and the strong force.*
Amir D. Aczel has been closely associated with CERN and particle physics for a number of years and often consults on statistical issues relating to physics. He is also the author of 18 popular books on mathematics and science.
By now you’ve heard the news-non-news about the Higgs: there are hints of a Higgs—even “strong hints”—but no cigar (and no Nobel Prizes) yet. So what is the story about the missing particle that everyone is so anxiously waiting for?
Back in the summer, there was a particle physics conference in Mumbai, India, in which results of the search for the Higgs in the high-energy part of the spectrum, from 145 GeV (giga electron volts) to 466 GeV, were reported and nothing was found. At the low end of the energy spectrum, at around 120 GeV (a region of energy that attracted less attention because it had been well within the reach of Fermilab’s now-defunct Tevatron accelerator) there was a slight “bump” in the data, barely breaching the two-sigma (two standard deviations) bounds—which is something that happens by chance alone about once in twenty times (two-sigma bounds go with 95% probability, hence a one-in-twenty event is allowable as a fluke in the data). But since the summer, data has doubled: twice as many collision events had been recorded as had been by the time the Mumbai conference had taken place. And, lo and behold: the bump still remained!
This gave the CERN physicists the idea that perhaps that original bump was not a one-in-twenty fluke that happens by chance after all, but perhaps something far more significant. Two additional factors came into play as well: the new anomaly in the data at roughly 120 GeV was found by both competing groups at CERN: the CMS detector, and the ATLAS detector; and—equally important—when the range of energy is pre-specified, the statistical significance of the finding suddenly jumps from two-sigma to three-and-a-half-sigma!
By now you’ve probably heard the widely reported news about the possible discovery of neutrinos that allegedly travel faster than light. The OPERA (Oscillation Project with Emulsion tRacking Apparatus) collaboration of almost 200 scientists working at the Gran Sasso underground laboratory in central Italy has discovered a phenomenon the physicists could simply not explain. For over three years, the scientists have been collecting data on the flight of neutrinos—those mysterious, nearly massless particles that can travel through anything at immense speed—originating in the SPS accelerator at CERN, near Geneva, and traveling underground all the way to Gran Sasso, 731 kilometers (about 450 miles) away. The experiment showed that the 16,000 neutrinos measured at Gran Sasso had traveled there through Earth’s crust at faster than light speed.
Facing a crowded lecture hall at CERN last Friday, Dario Autiero of the OPERA group explained how the researchers went to great lengths to remove any sources of error in their measurements: they measured distances using an extremely high-precision GPS called PolarX, measured time at the two locations to an accuracy of one nanosecond using cesium clocks, and accounted for the tides, Earth’s rotation, variations between day and night and spring and fall, etc. The statistical significance of the finding was six-sigma—meaning that the probability that the experimental result was a random fluke was only one in a billion. For a full hour after the presentation, Dr. Autiero was grilled by a roomful of physicists, and seemed to be able to account for all of the many potential errors brought up by the audience.
But physicists remain very skeptical. They want to see a confirmation of the findings from another experiment in a separate laboratory before they accept such a bizarre finding. After all, this result, if true, would appear to run against the spirit of Einstein’s special theory of relativity. When I showed the Gran Sasso paper to Nobel Laureate Steven Weinberg, he told me: “It looks pretty impressive, but I still think that this will go away.” The sentiment was echoed by almost every physicist I have spoken with since. The results seem mind-boggling. After all, nothing can go faster than light, right?