You may have encountered the terms “theory of relativity” or “general relativity” in physics. So, what is general relativity? Let’s explore the easiest way to understand this concept.
General relativity (or simply relativity) is a “cornerstone”, a fundamental element of modern physics. This theory explains gravity (or gravitational force) based on how space can curve, or more precisely, it links gravitational force with the changing shape of spacetime.
Illustration of a massive object bending spacetime. (Photo: PashaIgnatov/iStock).
History of General Relativity
Scientist Albert Einstein introduced this “general” theory in 1915, a decade after he proposed a “special” relativity theory that applied the speed of light in space to the assumption that the laws of physics do not change in any reference frame.
When he applied the concept of mass acceleration to that special theory, he realized that massive objects affect the dimensions around them (spacetime) in a way that those objects operate under the condition that they can attract other massive objects.
We can visualize this as matter existing within a spacetime structure, which weighs down on that structure, creating a “curve” that causes other nearby matter to slide toward it.
The Importance of General Relativity
Einstein’s mathematical equations of general relativity have been tested numerous times by scientists and remain the most accurate way to predict gravitational interactions, replacing the equations proposed by Isaac Newton centuries ago.
To this day, we do not have equivalent quantum field theories due to the enormous incompatibility; for example, quantum mechanics has many ways to consider concepts like infinity. However, if we also consider the concept of infinity in general relativity, the mathematics yields utterly nonsensical predictions.
Currently, modern physicists are still seeking to build a “quantum” version of general relativity.
