The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory

Physics is the scientific study of matter: the physical components that make up the universe and dictate the attributes and behaviors of all motion, energy, matter, and force within space and time. Physicist James Clerk Maxwell defined physics as “that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events” (Matter and Motion, 1878, 9). Physics is one of the oldest academic disciplines in human history. Some of the earliest intellectual work in recorded history in Greek, Egyptian, Chinese, and Mesopotamian cultures includes the investigation and exploration of physical matter and the attributes that make up the universe. The main endeavor of physics is to understand how and why the universe behaves the way it does.

Some important developments in physics include the move to replace the geocentric model of the solar system with the heliocentric model, proposed by Nicolaus Copernicus in 1543; Kepler’s laws of planetary motion, developed in 1609-1619; and Galileo’s groundbreaking work with telescopes and astronomy in the 17th century. The biggest early shift in physics came with Isaac Newton’s law of universal gravitation, which he developed alongside his three laws of motion in 1687. Newton’s laws of motion are as follows:

1) a body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force; 2) when a body is acted upon by a net force, the body’s acceleration multiplied by its mass is equal to the net force; 3) if two bodies exert forces on each other, these forces have the same magnitude but opposite directions (Thornton, Stephen T.; Marion, Jerry B. Classical Dynamics of Particles and Systems, 5th ed., 2004. 49).

“Newtonian” (or classical) physics became the accepted standard until modern physics began in the early 20th century with Max Planck’s quantum theory, proposed in 1900, and Albert Einstein’s theories of special relativity (1905) and general relativity (1915).

In The Elegant Universe, Brian Greene discusses these theories at length and then explains how relativity and quantum mechanics contradict each other, thus leading to the development of string theory. Since the publication of The Elegant Universe, several developments—including the completion of the Large Hadron Collider, the first visual confirmation of a black hole, and experimental evidence of the Higgs Boson (or Higgs particle)—have provided strong evidence in support of many concepts Greene presents in the book. Greene discusses these later developments in his subsequent books The Hidden Reality (2011) and Until the End of Time (2020).