A quick review of the unusual history of quarks

Image: Large Hadron Collider at CERN. Text: QUARKS--Tiny particles that comprise protons and neutrons. Learn the secret of this unusual word.

Today is Wednesday, so it’s time for our regular feature What is that? Here’s today’s term:

Quark–a tiny particle found in protons and neutrons

A quark is a tiny particle that can be found in any atom. Protons and neutrons, which make up the nucleus of an atom, are made of quarks.

[Read more about atoms and how they were once thought to be the smallest objects in the universe.]

What are the six “flavors” of quarks?

There are 6 types of quarks: up quarks, down quarks, top quarks, bottom quarks, strange quarks, and charm quarks. Some physicists also used to call top quark “truth” and the bottom quark “beauty” but that has apparently fallen out of style, which seems a shame. I like the whimsical names of strange, charm, truth and beauty.

Physicists refer to the different types of quarks as “flavors.” Maybe some of those physicists grew up working in an ice cream shop. (When I use “flavor” to describe something, I’m usually referring to the particular feel or mood I get when I’m reading a particular book.)

As I understand it, the names of the “flavors” don’t really mean anything. They are just tags that physicists placed on different types of quarks to tell them apart. I don’t mean that physicists literally put tags on quarks. Quarks are far too small for that. They are so small that even scientists can’t see them with microscopes. In fact, for decades, physicists just theorized that quarks existed.

Photo of the Globe of Science and Innovation at CERN headquarters.
Here at CERN headquarters near Geneva, physicists use particle accelerators to study subatomic particles like quarks. Photo by Faith Tucker.

In 1964, physicists Murray Gell-Mann and George Zweig, working separately and coming to their own conclusions, proposed the existence of quarks. At the time, they were just describing neutrons, protons, and other rarer particles made of quarks. Back then, there was not much evidence that quarks actually existed.

Cover of The Quark and the Jaguar: Adventures in the Simple and the Complex by Murray Gell-Mann
The Quark and the Jaguar: Adventures in the Simple and the Complex by Murray Gell-Mann

It took until 1968 for an experiment at the Stanford Linear Accelerator Center to provide some real evidence of quarks. And it took until 1995 for physicists to discover real-world evidence of the final quark flavor, the top quark.

The Quark has a literary heritage

Where did the name “quark” come from?

Physicists suggested different names for these tiny particles. It was Gell-Mann’s name–“quark”–that caught on. When thinking up a name, he first decided on the sound he wanted–“kwork.” Later, he ran across the word “quark” in Finnegans Wake by James Joyce and chose that spelling.

I’ve heard the word originally was a German word for curd cheese, and I’ve also read that it can mean “rubbish.” The use in Finnegans Wake might mean curd cheese, or it might mean something entirely different, like a cheer (or “croak”) made at a drinking establishment (a bar) or just a sound a bird might make.

Here’s the quote from Finnegans Wake:

Three quarks for Muster Mark!

Sure he has not got much of a bark

And sure any he has it’s all beside the mark.

Finnegans Wake by James Joyce

I find the source of the word and its original meaning to be as mysterious as the particle itself.

Discover and name your own particle!

Imagine you are a physicist. You discover an unknown particle!

  • What do you name it?
  • Why do you choose that name?
  • What does the particle do?

Please post your comments below.

Be stellar!

Matthew Cross

Orbits–Giant solar systems and tiny atoms both contain orbits. Let’s explore giant and microscopic worlds!

Old model of the solar system. Text: Orbits--Giant solar systems and tiny atoms both contain orbits. Let's explore giant and microscopic worlds!

The solar system is made of giant, orbiting bodies: planets

Eight planets orbit the sun, forming our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Asteroids also orbit the sun in the Main Asteroid Belt and the Kuiper Belt. The planets and the Main Asteroid Belt orbit the sun in a flat plane, like an invisible plate in space where the planets pass mainly through the plate. Sometimes they rise higher than the plate, sometimes they travel a little lower, but not by much.

The planets are very large objects. The sun, at the center, is the largest object in our solar system.

Tiny atoms are made of microscopic bodies that orbit each other

Cover of The Elegant Universe by Brian Greene

Next, let’s look at some of the very smallest objects in our universe: atoms. According to physicist and author Brian Greene, in his book The Elegant Universe, the ancient Greeks believed that “the stuff of the universe was made up of tiny ‘uncuttable’ ingredients that they called atoms.” The ancient Greeks thought the atom was the smallest building block of all matter. They said the atom was not made of anything smaller and could not be divided.

In the nineteenth century, scientists found that oxygen and carbon were made of the smallest pieces that could be recognized. “[F]ollowing the tradition laid down by the Greeks, they called them atoms. The name stuck,” Greene writes.

But it was later learned that oxygen and carbon atoms, and atoms of all the other elements, were made up of even smaller pieces. “Far from being the most elementary material constituent, atoms consist of a nucleus, containing protons and neutrons, that is surrounded by a swarm of orbiting electrons,” Greene writes.

Writers create new ideas by converting large to small or small to large

Sci Fi writers create fascinating creatures by turning something very small in the real world into something very large in their story. Consider the lowly worm. Frank Herbert turned the worm, a creature of a few inches, into his gigantic and fearsome sandworms of Arrakis in Dune.

Today, let’s do the reverse. Let’s take something very, very large–our solar system–and imagine it as small as an atom. If a sun were the nucleus of an atom, and if each electron orbiting around that nucleus were a planet, what kind of solar system can you imagine?

Build your mini-system!

Imagine your miniature solar system.

  • Would your planets be inhabited? Would the third planet–like Earth–support life?
  • Would travelers cross the vast distances between atoms to visit?
  • Where would your atom-sized solar system be floating? Would it be safe?

Please post your comments below.

Be stellar!

Matthew Cross