Discovery Science: Physics – Quarks, electrons, and co.

Earth Science: Physics and Technology – Physics – Elementary Particles

Even in ancient Greece, philosophers were already debating whether the world is made up of indivisible atoms. In the 19th and early 20th centuries, science seemed to have answered this question, thanks to modern atomic theory and the discovery of most of the chemical elements.

Today, however, we know that even the particles within atomic nuclei have their own inner structure. Quantum physics explores the characteristics of the most basic particles currently known in the universe.

Earth Science: Physics and Technology – Physics – Quarks, electrons, and co.

The elementary particles known today are unimaginably small-billions of times smaller than an atom. They are categorized according to qualities such as mass, charge, and interactions.

To better understand the structure of matter, think of the human body: it consists of organs such as the heart, liver, and bones, which are made up of countless cells. These cells are composed of molecules, which in turn are formed from atoms. The atoms, for their part, contain a small, relatively heavy nucleus and a shell of light electrons.

While the electrons are indeed basic particles, according to current knowledge, the atomic nucleus has a complex inner structure. Each nucleus contains positively charged protons and electrically neutral particles called neutrons, which are nearly equal in mass.

Protons and neutrons, in turn, have their own inner configuration; each contains three “quarks.” These particles—squeezed together within an unimaginably small space—can only be described with the help of quantum physics and relativity theory The energy of their mutual attraction is so great that particles within protons and neutrons are constantly forming out of the vacuum and disappearing again.

A basic principle of quantum physics is that all objects possess both wavelike and particle- like properties. Thus even electrical and nuclear forces operate in particle-like ways, through force-carrying particles. One variety of these is already familiar: the photon. This quantum (indivisible unit of energy) of electromagnetic radiation is the carrier for all electrical and magnetic interactions.

In addition, the electron has two heavier siblings: muons (//) and tau (r) particles. The so-called up and down quarks, which are found within protons and neutrons in atomic nuclei, also each have two larger relatives.

In addition, the electrons u. and teach have partners called neutrinos, which are electrically neutral and almost—but not completely- without mass. All known matter in the universe is composed of these particles: quarks, electrons, and neutrinos.


IN THE LATE 1990s, astronomers discovered that we know significantly less about the universe than previously thought: observable matter and energy (quarks, electrons, and force particles) account for only 4% of the total matter and energy in the universe.

23% is composed of unknown mass, detected through its gravitational influence (dark matter), and nearly three- quarters of the energy is so-called dark energy, about which we know practically nothing.