In 1897 J.J. Thomson stood before the Royal Society and made the case for a charged particle a thousand times less massive than the hydrogen atom. He had discovered the electron. Initially many in the room didn't believe him. Atoms were considered the smallest bits of matter and physics and chemistry were concerned with arranging their properties on periodic tables. But Thomson's work proved solid. Then a bit more than a decade later Ernest Rutherford discovered the atomic nucleus. There was something very small with a positive charge at the center of ever atom with electrons zipping around in a large amount of empty space "like a fly in a cathedral".
Much of the revolution in atomic and quantum physics came out of the Cavendish Laboratory at Cambridge - a place that represents one of the greatest inventions of the 19th century. It had been set up with funding from the Chancellor of the University - William Cavendish - as something of a reaction to worries about falling behind other institutions that were engaged in understanding telegraphy. Cavendish did something rather dramatic. Rather than work on the immediate problem he set up an institution to focus on fundamentals and hired James Clerk Maxwell to run the place. Maxwell started setting up a laboratory of shared resources and culture, but died not long after.
The next director, Lord Rayleigh, brought systematic instruction and further focused on studying the fundamentals rather than applied work. Maxwell's earlier work sorting out electricity and magnetism was initially unwieldily, but it was clear light was made of electromagnetic waves and people realized wireless communication might be possible. That would be a big thing - telegraphy without those expensive wires. Rayleigh was asked to work on it, but suggested it would be far too expensive in terms of equipment they didn't have. Instead the path would be less expensive explorations trying to stay at the frontier. Not long afterwards Hertz, working in Germany, discovered how to do wireless communication. The Cavendish Lab did more impressive work - they set the path for the next century.
Hertz was making use of the unification of the electricity and magnetism that Maxwell had figured out two decades before. In Maxwell's model there was an electromagnetic field that allowed waves to propogate through a hypothetical substance called the luminiferous ether. It wasn't exactly right - ether was shown to not exist, but the notion of fields traveling through nothing persisted. It gave physics a new way of thinking about influence at a distance.
So what is a field? Usually they're described as a set of values at each point in space. Like temperature, air pressure, wind speed and so on. Physicists have another way of thinking about a different kind of field that is a bit confusion to those on the outside. That's the kind of field that's relevant here.
Before Maxwell there was Michael Faraday - perhaps the last of the great non-mathematical physicists. . Pick up a couple of magnets and hold them so they're repelling each other - say north pole to north pole. As you push them together you feel the force increasing. You can't see it, but Faraday said there's something real there. He called them lines of force - it later was called the magnetic field. He was first to understand if you move a coil of wire through a magnetic field, a current is induced in the coil. He had discovered a link between electricity and magnetism. It stunned audiences at his lectures Fields were a deep thought .. it took us about a century and a half to really appreciate the depth.
Over the next 150 years a revolution in physics taught us about quantum mechanics. Rather than getting into the weeds just note the bottom line is energy comes in discrete lumps rather than being continuous.. The exciting part comes when you combine the discrete nature of quantum mechanics with Faraday's continuous smoothly varying fields. Quantum field theory tells us the discrete bits of the electromagnetic field come in little chunks we call photons. Skipping over an enormous among of work and a few dozen Nobel Prizes, the remarkable thing is this general idea applies to every particle in the universe. For each type of particle there's a field filling the universe .. for example an electron field. Little ripples in this fluid get tied into little bundles of energy and, in this case, the bundle of energy is what we call the electron. All of the electrons in the Universe are just waves in the same electron field - think of it as sort of a fluid - that fills the entire Universe.
By 1970 it was known in addition to the electron field are two quark fields. You may have learned protons and neutrons are each made of two types of quarks: the proton is two up quarks and a down quark and the neutron is two down quarks and an up quark.1 In this interpretation there are no particles in the Universe.. just ripples in fields. Now we have come down from the periodic table with over one hundred elements to something much simpler: an electron, an up quark, a down quark and something called a neutrino. Or more fundamentally an electron field, an up quark field, a down quark field and a neutrino field.
It's a more fundamental way of thinking about things, but it's also an oversimplification. In the spirit of oversimplification here's the result. For some completely unexplained reason Nature like to repeat ins triplicate. There are three families of electron like fields, three of up quarkish fields, three of down quarkish fields and three families of of neutrinoish fields. Add to this four force fields and now there are sixteen fundamental fields .. plus another called the Higgs field which is partly responsible for giving these ripples mass. (note - the image shows particles .. just think of them as fields) Collectively this is know as the Standard Model.
The idea of seventeen fundamental fields representing everything on Earth may seem unnatural, but where precision measurements can be made they compare with theory to astounding accuracy - much better than any other theory in any branch of science. It has also been predictive of things we didn't know existed.
The equation for the Standard Model is somewhat ugly. It doesn't incorporate gravity. Many suspect something more fundamental exists, but just because we might want it doesn't mean Nature works that way - maybe it is fundamentally messy. On top of that the Standard Model describes only describes conventional matter which is only about five percent of the known mass energy of the Universe. Another twenty seven percent is dark matter - something which we can detect indirectly, but have no real understanding of.2 Even more mysterious is the remaining sixty eight percent that we call dark energy.
Perhaps the Standard Model isn't the ultimate description of what we're made of.3 For now it's more fundamental than saying we're made of particles or atoms even though those are usually more convenient ways to deal with anything at the scale we're used to. But I like to think there's something poetic about seeing each of us as constellations of tiny field disturbances bound together by force fields. We're part of an enormous family of these constellations that spread through the Universe. Our personal constellations are conscious and are capable of wondering if other constellations may have similar thoughts..
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Last year I wrote another short piece about fields and what is known as the vacuum. Both of these are very brief, but perhaps give an idea of the most successful bit of physics - arguably science - to date.
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1 Up and down are just labels and nothing more... other than proof physicists are very poor when it comes to naming things.
2 I once calculated about 250 grams of dark matter is streaming through the Earth at any given moment.. roughly a squirrel's worth of dark matter. Also dark is a bad term.. it doesn't interact with conventional matter so in it's really perfectly transparent matter.
3 There have been a few theories designed, among other things, to add gravity. Mathematically String Theory is appealing, but so far there are no signs that's how Nature works. It may well be a cold trail.
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