The equation describing the geometry and mass-energy distribution of a homogeneous and isotropic universe is known as:
- The Einstein Equation
- The Friedmann Equation
- The Robertson-Walker Equation
- The Hubble Equation
None of the above. Four have gotten into the act.
http://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric
The Friedmann Equation
The equation describing the geometry and mass-energy distribution of a homogeneous and isotropic universe is known as the Friedmann Equation.
To understand why this equation is named after Friedmann, we need to delve into a brief history of cosmology. In the early 20th century, Albert Einstein developed his theory of general relativity, which revolutionized our understanding of gravity. General relativity describes the gravitational interactions between matter and energy and provides a framework for understanding the structure and evolution of the universe.
Around the same time, a Russian physicist, Alexander Friedmann, independently derived a set of equations that describe the dynamics of a homogeneous and isotropic universe within the framework of general relativity. These equations, now known as the Friedmann Equations, allowed for the possibility of an expanding or contracting universe, challenging the previously held notion of a static universe.
The Friedmann Equations take into account various factors, such as the density of matter, the curvature of space, and the expansion rate of the universe. They form the foundation of modern cosmology and are crucial in understanding the evolution and behavior of our universe.
So, the correct answer to your question is the Friedmann Equation.