But atoms, it was discovered, are made up of even smaller parts called protons, neutrons, and electrons. The protons and neutrons are in the center of the atom, called the nucleus, which is one-millionth of a billionth of the volume of the atom.
If an atom were blown up to the size of a stadium, the nucleus would be the size of a grain of rice, but it would weigh more than the stadium.
The discoveries continued as technology was developed to split those particles, which led to the discovery that those particles are actually made up of even smaller particles. And then technology was developed to split those particles and it was discovered that those particles are actually made up of even smaller particles. And then technology was developed to split those particles . . .
Down and down it went,
smaller and smaller,
further and further into the subatomic world.
The British physicist J. J. Thomson discovered the electron in 1897, which led to the discovery of an astonishing number of new particles over the next few
years, from
bosons and
hadrons and
baryons and
neutrinos
to
mesons and
leptons and
pions and
hyperons and
taus.
Gluons were discovered, which hold particles together, along with quarks, which come in a variety of types—
there are up quarks
and down quarks
and top quarks
and bottom quarks
and charmed quarks
and, of course,
strange quarks.
When an inconceivably small particle called a muon was identified, the legendary physicist Isaac Rabi is known for saying, “Who ordered that?”
By now somewhere around 150 subatomic particles have been identified, with new technology and research constantly emerging, the most impressive example of this happening at a facility known by the acronym CERN, which is near the Swiss–French border. Workers at CERN, an international collaboration of almost eight thousand scientists and several thousand employees, have built a sixteen-mile circular tunnel one hundred meters below earth’s surface called the Large Hadron Collider (LHC). At the LHC they fire two beams at each other, each with 3.5 trillion volts, hoping that in the ensuing collision particles will emerge that haven’t been studied yet.
Physicists have talked with straight faces for years about how with this unprecedented level of energy and equipment and billions of dollars and the brightest scientific minds in the world working together they might be able to finally discover that incredibly important, terribly elusive particle called the . . .
Higgs Boson.
(Which they did. Go ahead, Google it. It’s incredible. Even if it sounds like the name of a southern politician.)
Now, the staggeringly tiny size of atoms and subatomic particles is hard to get one’s mind around, but it’s what these particles do that forces us to confront our most basic assumptions about the universe.
Many popular images of an atom lead us to think that it’s like a solar system, with the protons and neutrons in the center like the sun and the electrons orbiting in a path around the center as our planet orbits the sun.
But those early pioneering scientists learned that this is not how things actually are. What they learned is that electrons don’t orbit the nucleus in a continuous and consistent manner; what they do is
disappear in one place and then appear in another place without traveling the distance in between.
Particles vanish and then show up somewhere else, leaping from one location to another, with no way to predict when or where they will come or go.
Niels Bohr was one of the first to come to terms with this strange new world that was being uncovered, calling these movements quantum leaps. Pioneering quantum physicists realized that particles are constantly in motion, exploring all of the possible paths from point A to point B at the same time. They’re simultaneously everywhere and nowhere.
A given electron not only travels all of the possible routes from A to B, but it reveals which path it took only when it’s observed. Electrons exist in what are called ghost states, exploring all of the possible routes they could take, until they are observed, at which point all of those possibilities collapse into the one they actually take.
Ever stood on a sidewalk in front of a store window and seen your reflection in the glass? You could see the items in the display window, but you could also see yourself, as if in a fuzzy mirror. Some of the light particles from the sun (called photons) went through the glass, illuminating whatever it was that caught your eye. Some of the particles from the sun didn’t pass through the glass but essentially bounced off it, allowing you to see your reflection. Why did a certain particle go through the glass, and a certain other particle not?
It can’t be predicted.
Some particles pass through the glass;
Some don’t.
You can determine possibilities,
you can list all kinds of potential outcomes,
but in the end, that’s the best that can be done.
The physicist Werner Heisenberg was the first to name this disturbing truth about the quantum world: you can measure a particle’s location, or you can measure its speed, but you can’t measure both. Heisenberg’s uncertainty principle, along with breakthroughs from Max Planck and many others, raised countless questions about the unpredictability of the universe on a small scale.
As more and more physicists spent more and more time observing the universe on this incredibly small scale, more truths began to emerge that we simply don’t have categories for, an excellent example of this being the nature of light.
Light is the only constant, unchanging reality—all that curving and bending and shifting happens in contrast to light, which keeps its unflappable, steady course regardless of the conditions. But that doesn’t mean it’s free from some truly mind-bending behavior. Because things in nature are either waves or particles. There are dust particles and sound waves, waves in the ocean and particles of food caught in your friend’s beard. That’s been conventional wisdom for a number of years.
Particles and waves.
One or the other.
