Beyond the God Particle (6 page)

Democritus inherited the moniker “the laughing philosopher,” as he evidently found most of the ideas of other contemporary philosophers to be rather humorous, if not ridiculous. We can imagine him heckling Plato during a lecture in some curia, circa 400 BCE, perhaps asking a subtle and detailed question about a certain chemical reaction about which Plato could not begin to answer:

P: And the natural order and simplicity of nature is simply that all things can be resolved to the five “elements,” the “air,” the “fire,” the “water,” the “earth,” and the “quintessence,” and that's all of it.

D: Master, are these elements transmutable into one another?

P: No, truly not, sir, for as I say, they are
elemental
.

D: But of what element is the brilliant light of the sun?

P:
(pause)
I suppose…a form of quintessence as it does flow though space which is filled of quintessence and so it must be such.

D: And, master, of what element is papyrus?

P: Surely, papyrus is a form of the earth as it comes from the earth.

D: So, master, if I place a gem of spherically shaped quartz between the position of the sun, and that of a papyrus scroll, which you say is a form of the earth, I can direct, or “focus,” the sun-light, a form of quintessence, upon the papyrus and I can produce a fire. Have I not converted the quintessence into the fire or the earth into the fire?

P: I do not believe this can happen, sir.

D: I have set up the experiment here, master
(Democritus directs Plato and the audience to a window at which he has an apparatus. With the apparatus he focuses sunlight onto a piece of scroll paper, and it shortly smokes then bursts into flames)
.

P:
(impatiently)
Well, if this is not a ruse then perhaps…perhaps light is really a form of fire, so you have not converted anything into anything else.

D: But if I should send the light, that you now say is fire, into an urn of oil, it becomes dark…where has the fire now gone? Has it become the oil which you would say is the earth?

P: Indeed…
(pause, stammer)
well, perhaps it is as we said quintessence…

D: Then as I burn the papyrus
(the paper continues to smolder)
, which is a form of the earth, in the fire, and the smoke rises into the air, and the papyrus disappears, have I not converted the earth into air?

P:
(long indignant pause)

D: Bbbbwwwaaahahahaha…
(Democritus bursts into a sneering and callous laughter)
.

Democritus wanted real and detailed answers to scientific questions. From Democritus we got a conceptual basis of the elements. These elements, he reasoned, must have certain
complex dynamical properties
that cause them to ultimately shape and define the behavior of matter. The multitude of various properties of ordinary matter are
reduced
to the more fundamental properties of atoms. Some elements were envisioned to be little spherical balls that could freely flow (e.g., liquids), while others had hooks and could form stiff structural bonds (metals), and still others had block-like shapes that might make regular crystalline arrays (diamond or quartz). The theory
had to explain all known phenomena correctly, perhaps even predict new observable phenomena, the standard to which science holds all theories.

Of course, this was an ultra-ambitious undertaking in those days. Democritus had no microscopes, or particle accelerators, to test and validate his hypothesis. But his reductionist hypothesis implied rules and organizing principles for chemistry. Democritus dubbed the basic constituents of matter “atoms” from the Greek
atmos
(
indivisible
). Out of these basic building blocks we can construct more complex objects and the forms and shapes of all that we see. The behavior of the large-scale physical world is thus emergent from the fundamental properties of atoms.

This is a wholly modern view of the physical world, as well as one of the tasks of science. While, in Democritus's theory, certain materials could change and rearrange their structure under chemical reactions (e.g., burning them, letting them rot, or dissolving them in water), the underlying atoms were immutable, unchangeable, invariant. His theory was useful and offered a prescription for further research. Here was the basic tenet of “fundamental particles,” and their role as the irreducible components of all things throughout the universe, which sculpt and shape the world through their own intrinsic properties.

Alchemists over the subsequent centuries went to work. They never succeeded in turning the element lead (Pb) into the element gold (Au), or achieving any other elemental transmutation, for that matter. In countless attempts to do so they merely rearranged elements within the many exotic compounds, but they provided the service of amassing an enormous empirical “database” of recipes and processes and properties of chemicals that formed the foundation of the science of chemistry. In this sense, Democritus's theory was tested, found to be correct, but has been so significantly enlarged in detail by later science that it ultimately proved to be more of a philosophy, a prescription to actually do the hard work of science, and not to be merely contented with a dismissive shake of the wrist, invoking “air,” “fire,” “earth,” “water,” and “quintessence,” panacea for lack of a deeper understanding.

What we come into contact with on a daily basis, the “everyday matter,” is the first layer of the “onion of nature.” It is comprised of “molecules,” which are either large or small groupings of atoms. Salt (NaCl), water (H
₂
O), oxygen in the air we breathe (O
₂
), and methane (CH
₄
), the gas we use to
heat our homes, etc., are all molecules, composed of combinations of the more fundamental elements or atoms. Molecules can be broken down chemically into their constituent atoms, which can then be rearranged into other molecules. Just light a match to a certain mixture of oxygen molecules and methane molecules, and these will rapidly rearrange to form water molecules and carbon dioxide molecules, releasing a lot of heat.
²
On the other hand, sodium (Na), chlorine (Cl), hydrogen (H), oxygen (O), carbon (C), and so on, are all atoms, or “elements.” These are invariant, or unchanging, in chemical reactions—they are the “fundamental particles” of chemistry.

The total numbers of these atoms never change in chemical reactions—the atom of gold (Au) cannot be changed into lead (Pb) by chemical reactions. The atoms cannot be further subdivided without doing things that aren't possible in a high school chemistry lab. To smash atoms apart, into “smithereens,” takes us beyond the realm of chemistry. It takes us into a deeper layer of the onion of nature, the realm of atomic and nuclear physics, eventually into the realm of quarks, leptons, and gauge bosons. These are, today, the true “fundamental particles” of nature, perhaps to be replaced by smithereens in some science of the future.

By the mid-nineteenth century, based upon the accumulated knowledge of all the known chemical processes, the elements, or atoms, were classified according to their properties by the great Russian scientist Dmitri Mendeleev. This classification scheme is called the
Periodic Table of the Elements
. The Periodic Table was a stunning summary of the thousands of years of alchemy, chemical science, and simply messing around with matter. It represented the reduction of the virtual infinity of molecules into a simple list of approximately 100 atoms found in nature (slightly more than 100 atoms is today's count; it was significantly fewer at the time of Mendeleev; many elements, such as helium, were discovered later, and many of the heaviest elements are so radioactively unstable that they must be artificially produced in particle accelerators and are not to be found on our old high school chemistry classroom wall charts). The Periodic Table represented a pattern of repetitive chemical behavior in the properties and forms of atoms as one goes to heavier and heavier atoms. By its complexity, however, it suggested that atoms may, themselves, be further reduced and may have internal structure, and that a deeper layer of
subatomic matter
must exist.
³

THE “PHYSICS AS AN ONION” METAPHOR

Mendeleev's table was the beginning of the modern era of the science of matter. To understand this, one must appreciate that nature is, empirically, organized much like an onion. Nature has different layers of phenomena and structures as one descends to smaller and smaller distance scales. And, going downward to shorter distances, we discover, is equivalent to going to higher and higher energy scales (higher “energy per particle”; we'll define this more carefully momentarily). Although all of nature is governed by the same underlying fundamental laws of physics, the structures of complexity that we see in nature seemingly occur at different “strata” of phenomena, like an onion, and each stratum of nature is characterized by the energy needed to probe it.

What do we mean by “the energy needed to probe it”? We have to get a little bit technical here and introduce you to the common currency in talking about energies of fundamental particles and atoms: the
electron volt
or “eV.”
⁴
Most of the science of chemistry, that is, the amount of energy involved in most chemical reactions, lies in the range from about 0.1 to 10 eV per atom. This means that when a given atom enters into a chemical bond with another atom (or an existing molecule) to form a new molecule, roughly 0.1 to 10 eV of energy is released. This is energy that comes from the forces that produce a chemical bond between two atoms, and it is typically released in the form of light, or the energy of motion, called
kinetic energy
.

The released energy is usually converted into heat (which is the aggregate random motion of atoms in a material), but it can also be seen as the light emitted from a fire or heard as the boom from a firecracker. You can usually see the released chemical energy with your eyes because a single visible particle of light, the
photon
, carries about 2 to 3 eV of energy—after all, the light entering our visual system that allows us to see is processed by various chemical reactions in our eyeballs and our brain, and so the perception of light entirely happens at the chemical energy scale.

If we can probe molecules with a source of energy of about 0.1 to 10 eV, we can often cause a chemical reaction to occur. For example, striking a match in a mixture of methane (CH
₄
) and oxygen (O
₂
) will provoke a rapid chemical reaction—a flame—yielding carbon dioxide (CO
₂
) and water (H
₂
O).
⁵
The match is generating photons and kinetic energy of motion of atoms of about an eV each from its own burning (usually oxygen combining
with phosphorous). These energetic particles strike the methane and oxygen and nudge them into reacting, which emits more photons. Then more and more energy is released in a chemical chain reaction, and
VAVOOM
, you might have an explosion.

The physics, that is, the motion and interactions of electrons and atoms in chemical reactions—
the stratum of the chemical reactions
—is very much independent of, or decoupled from, what is going on in other stratums of nature. For example, to analyze everyday chemical phenomena, one need not be bothered by such complications as the detailed motion of the protons and neutrons that comprise the inner atomic nucleus and that exist on much smaller distance scales than the overall size of the atom. Nuclear physics is a far different energy stratum, measured in millions of electron volts, or “MeV” (see
note 4
), compared to the lowly 0.1 to 10 eV stratum of chemistry. Nor need we, in studying chemistry, be bothered by the slow, lugubrious astronomical motion of the earth in its orbit around the sun. In fact, it is the relative motion of atoms and the electrons within the atoms that matters for chemistry. Thermal effects, the random motion and collisions of atoms due to heat, are typically about 0.1 eV per atom at room temperature, and they increase with temperature and therefore do have effects on chemical reactions (i.e., “cooking”). But the motion of the earth in its orbit is a common, uniform drift of the assemblage of all of the earth's atoms, producing no high-energy inter-atomic collisions. Of course, if an asteroid collides with the earth, the relative motion of the asteroid's atoms hitting the earth's atoms involves very high energies, and very serious chemistry, even nuclear physics, will occur!

While the triumph of Mendeleev's Periodic Table of the Elements formed a basis for understanding all chemical reactions, we learned in the early twentieth century that the atoms themselves are not truly elementary: they are composed of even smaller, more basic objects. To understand this we must probe into the atom. And, as it goes with probes, the probe we use to analyze something should preferably be smaller than the object we wish to probe. If the probe is bigger than the object probed, it becomes a bludgeon or battle-ax, and battle-axes don't work so well for dissecting tiny things or performing dental surgery, etc.