Hard Science

The curse attributed to the Chinese - “May you live in interesting times”- seems to be especially apt today. Whether it’s the explosion of sexual genders at home -- following the discovery that male and female are insufficient -- or the resurgence of barbaric medieval religions abroad, modern times sure are interesting.

Modern science has also proven to be interesting, and popular. From “The Big Bang Theory” (a TV sitcom) to “The Theory of Everything” (a tragic love story), science has become hip. Indeed, one can imagine overhearing millennials at a cocktail party: “I f***ing love science!!” Here “science” should be in quotes since the old-timers among us would not recognize what today passes for science. Indeed, what many moderns love is scientism, a secular replacement for religion, with its scientist-priests surrounded by a cult of personality (See starman Neil deGrasse Tyson, “the fetish and totem of the extraordinarily puffed-up nerd culture that has of late started to bloom across the United States.”)

In the real world of the hard sciences, most of the hard work seems to be done. For example, in physics the theories of Newton, Maxwell, Heisenberg, Einstein, Dirac, Feynman et al provide the underpinnings of our modern understanding of the inanimate world and the tools to create new technologies. These scientific theories are important. Since the 1970’s, however, some physicists have turned their attention to the extremes, from the real physical world we live in to the singularities and the multiverse. The results have been disappointing and mostly unimportant.

Fields of Dreams

Let us begin with the very small. The Standard Model of Particle Physics is the combination of quantum electrodynamics (QED), theories of the weak and strong forces and the quark model of the fundamental particles. It has been called the “theory of almost everything” (from the book of the same title by Robert Oerter). In fact, the only part of the Standard Model that has been rigorously tested is QED. Theories of the weak and strong forces were modelled on the exchange of virtual particles borrowed from QED. (“Because physicists have only been able to think of the same damn thing, over and over again.” Feynman, “QED” p149). The quark model was formulated to make some sense of the zoo of fundamental particles being created in the new atom smashers, the “fields of dreams” built for physicists. Every collision produced new ephemeral particles that needed to be measured and categorized. Yet the Standard Model only replaced one zoo-full of particles with another (something like 40 quarks, anti-quarks and gluons) that have strange properties never seen before. In fact nobody has ever observed a single quark, but the theory explains that issue by postulating yet another strange constraint.

Physicist John Baez has a rating scale of potentially revolutionary contributions to physics; he calls it the “crackpot index.” The index gives, for example, 5 points for a thought experiment that contradicts the results of an actual experiment, 10 points for each favorable comparison of oneself to Einstein, and so on. As in golf a high score is bad. I’d like to suggest 20 points for claiming to have the “standard model” and 50 points for a “theory of everything.” Yet physicists from Einstein’s time to the present have been in search of the Holy Grail: a Grand Unified Theory (GUT: 30 points) or “theory of everything.” (50)

Enter String Theory. Underlying all the particles, Superstring Theory (It’s already been upgraded by a second “revolution”) assumes there are more fundamental entities having some properties of strings. The basic “strings” are mighty small, with a length equal to the “Planck length” (about 10^-33 cm). Like a violin string under tension, the quantum strings support standing waves, and the fundamental particles of matter are thought to correspond to different vibration frequencies, with masses given by hν/c². The basic idea is pretty simple, but the theory quickly becomes muy complex and unsettling.

Superstring Theory requires 10 dimensions of space, a major problem since the 10 dimensions must be “compactified” to the physically realizable 4 dimensions, and there appears to be an infinite number of ways to do that. The current thinking is that the theory allows an astronomically large number of physical possibilities (and universes), so it seems impossible to ever test it. Peter Woit has called the theory “Not Even Wrong,” the title of his recent book. Dick Feynman said that “String theorists don’t make predictions, they make excuses.” Normally such criticism would cause one to run for the exits, but string theorists seem to be a hardier lot, not easily frightened.

Multiverses

In the land of the very large, theories of the universe, while beginning on a firm footing, have lately gone off the deep end. The cosmological models based on General Relativity had some successes. To the extent it has been possible to test General Relativity, its predictions have always been borne out by experiment (gravitational light shifts, precession of planets, bending of light, gravitational time dilation effects on GPS, etc, etc.) The existence of Black Holes is consistent with stellar orbits near galactic centers and with the current understanding of quasars. The predicted expansion of space, while non-intuitive, is consistent with the observed cosmological redshifts. The existence of 3 degree background radiation and the primordial amounts of the lightest nuclei (but not Lithium) also support the standard model. So far it’s a reasonable theory.

The problems began when theorists tried to explain details of the model relating to the first femto-atto-wink by invoking new stuff, from “dark matter” and “dark energy” to “inflation” that have no basis in experimental fact. Today much of experimental cosmology has devolved into massive searches for the strange stuff and probes of the horizon. (Astronomer Mike Disney: “Statistical studies of faint objects can keep a career going for ages without the need for a single original thought.”)  On the theoretical side, the cosmologists have joined forces with the particle physicists in trying to invent new ways of explaining the singularity.

It seems that a more productive enterprise would involve questioning and improving the theoretical bases of the standard cosmological model. For example, the assumptions of homogeneity and isotropy that underlie standard cosmology are gross approximations. General Relativity has only been tested in the weak field approximation that is nothing like the early universe as it is theorized. Furthermore, when gravitational forces are strong enough quantum effects must be taken into account. Thus a quantum theory of gravity would be needed.

The current leading contender is Loop Quantum Gravity which tries to quantize space itself, in other words, treat space like it comes in small chunks. LQG takes the smooth fabric of space-time in General Relativity and asks whether, like a normal fabric, it might be made up of smaller, Planck scale fibers woven together into quantized volumes. LQG theory predicts that the speed of light has a small dependence on energy. Photons of higher energy travel slightly slower than low-energy photons. The effect is very small, but it amplifies over long distances. Unfortunately for LQG, the Fermi Gamma-ray Space Telescope results released in 2009 refute this prediction. (The prediction was debated on an episode of The Big Bang Theory, where a young couple on both sides of the LQG-String debate argue about how their children will be raised: loopy or stringy.) 

Real Physics

An alternative to all this speculation would be to compactify our hubris. Imagine that the “initial state” of the universe was not the Big Bang singularity but rather the photon-dominated stage that we identify in the present model as a few minutes after the singularity. In our initial state, the fundamental forces and particles already exist and are moving at non-relativistic speeds. The matter density is low enough that General Relativity works just fine. A little bit after our new t = 0 the protons plus neutrons begin to form the lighter nuclei. Quantum gravity, inflation and exotic particles are not needed. Nor is Superstring theory. What happened before our new beginning? Who cares; it’s not important.

Thousands of physicists could give up chasing daydreams and return to doing physics that mattered. (If they are qualified. Sheldon Glashow wonders whether physicists whose expertise is limited to string theory will be employable when the “string snaps.”) And for those of us who are skeptics, we can stop wasting time trying to discredit the Big Bang and spend our time working on the unsolved problems in physics. There are so many. Some examples taken from Wikipedia:

1.    What mechanism causes certain materials to exhibit superconductivity at higher temperatures?

2.    What's the momentum of photons in optical media?

3.    Are there non-local phenomena in quantum physics other than entanglement? Are they useful?

4.    Why is gravity so much weaker than electromagnetism?

5.    How can plasmas be confined long enough and at a high enough temperature to create fusion power?

6.    How can turbulence be understood and its effects calculated?

7.    What is the lifetime of the proton and how do we understand it?

8.    Are all the measurable dimensionless parameters that characterize the physical universe calculable in principle?

9.    How do genes govern our body, withstanding different external pressures?

10. Is dark matter responsible for the observed rotational speeds of stars revolving around the center of galaxies, or is it something else?

The last question has been addressed by Feng and Gallo who show that dark matter is not necessary.

Let’s all get back to doing real physics.

 

A few good books about the crisis in physics are the following:

The End of Science by John Horgan

Bankrupting Physics by Alexander Unzicker and Sheila Jones

Not Even Wrong by Peter Woit

The Trouble with Physics by Lee Smolin