The String Theory—what is it?

If you're involved in the physics world or just science overall, there's a neat chance you've heard of the string theory. But what exactly is it? Where is it applied? And is it actually true? Let's take a look.

From Atoms to Quarks:

It's well known that atoms are one of the smallest fundamental building blocks of matter and make up everything in life. They make up our cells, our furniture, and even the vast universe. But it goes deeper: Atoms are made up of protons, neutrons, and electrons. The proton and neutron are located in the nucleus, or the center of an atom, while the electron orbits it. Even deeper, protons and neutrons are made up of smaller particles called quarks. Quarks are considered to be fundamental particles, meaning they're not made up of any other components and can not be broken down further. There are six different types of quarks (also known as flavors): up, down, charm, strange, top, and bottom. Each one is characterized by its unique properties, including mass and charge. Different combinations of these quarks form the protons and neutrons in atomic nuclei.

The Birth of String Theory

In the late 1960s, the strong nuclear force that binds together protons and neutrons presented a major challenge for physicists. At the time, it was believed that all matter and forces were made of point-like particles. But it didn't fully explain particle scattering, which occurs when a particle collides with an atom and changes its direction of motion.

Physicist Gabriele Veneziano researched the strong force in hopes of finding an answer for the particle scattering. He came up with a mathematical formula (later known as the Veneziano amplitude). Surprisingly, other physicists interpreted this formula not as a point particle but as tiny vibrating strings, which eventually led to the string theory.

The "Theory of Everything?"

The string theory states that the universe is constructed by tiny vibrating strings, smaller than the smallest subatomic particle. And based on the string's vibration, it corresponds to different types of particles, such as electrons and photons. This theory, also known as the "Theory of Everything," was used to justify a unified relation of two of the most important theories in physics, general relativity (which explains gravity on a large scale) and quantum mechanics (which governs the subatomic world). These two theories usually don't cross over, but the string theory provided hope for a union.

However, as much as this theory provided many scientific potentials, it also came with many challenges. It couldn't be proven since it's currently untestable. These strings are so small, possibly near the Planck length, and we have no technology capable of detecting them. This makes the string theory highly conjectural, as it remains unproven.

Extra Dimensions?

The theory also provided a lot of new questions. It is an established fact that there exist four dimensions, but the string theory suggests the universe has ten or eleven dimensions in total, one being a temporal dimension (time). String theorists describe the extra dimensions as being compactified or curled up into a very small space to the point where you can't observe them directly.

So... What Now?

So where does that leave us? The string theory is one of the most fascinating scientific theories ever proposed. It offers hope as a possible "Theory of Everything"—but also raises questions we don't have the answers to yet. For now, it's a theory that might be —a theory waiting to be proved or disproved.

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Work Cited:

Britannica, The Editors of Encyclopaedia. “String Theory.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., https://www.britannica.com/science/string-theory.

Howell, Elizabeth. “What Is String Theory?” Space.com, 22 Feb. 2013, https://www.space.com/17594-string-theory.html.

Greene, Brian. “The Elegant Universe.” YouTube, uploaded by NOVA PBS Official, 28 Oct. 2011, https://youtu.be/Da-2h2B4faU?si=aMeH23oisNDe_4C1.