Friedmann Equation Calculator

The Friedmann Equation is a fundamental concept in cosmology that describes the expansion of the universe. It is derived from Einstein's field equations of general relativity and provides insights into the evolution and dynamics of the cosmos. This tutorial aims to explain the Friedmann Equation and the associated calculations and formulas. It delves into the discipline of cosmology, which is a branch of physics that focuses on the study of the universe's large-scale structure, evolution, and properties.

Friedmann Equation Calculator
Friedmann Equation Calculator Results
Friedmann Equation =
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Example Formula

The Friedmann Equation is expressed as:

H² = (8πG/3) ρ - (kc²/R²)


  1. H: represents the Hubble parameter, which describes the rate of expansion of the universe.
  2. G: denotes the constant of gravitation, a fundamental constant in physics.
  3. ρ: refers to the density of matter and energy in the universe.
  4. k: represents the curvature parameter, which describes the spatial curvature of the universe. It can take values of +1, -1, or 0, corresponding to a closed, open, or flat universe, respectively.
  5. c: denotes the speed of light in a vacuum.
  6. R: represents the cosmic scale factor, which describes the expansion of the universe as a function of time.

Who wrote/refined the formula

The Friedmann Equation is named after the Russian physicist Alexander Friedmann, who derived it in 1922 as a solution to Einstein's field equations of general relativity. Friedmann's work significantly contributed to the development of modern cosmology and our understanding of the universe's expansion. Over the years, the equation has been refined and further explored by numerous physicists and scientists in the field of cosmology.

Real Life Application

The Friedmann Equation has profound implications for our understanding of the universe and its evolution. It helps cosmologists and astrophysicists study the dynamics of the cosmos, including the expansion rate, the presence of dark energy, and the fate of the universe. The equation allows us to make predictions about the future of the universe and its large-scale structure, guiding our exploration of the cosmos and shaping our understanding of the universe's origin and evolution.

Key individuals in the discipline

Alexander Friedmann's contributions to cosmology and the derivation of the Friedmann Equation were groundbreaking. His work laid the foundation for our understanding of the expanding universe and the principles of modern cosmology. Other key individuals in the field of cosmology include Albert Einstein, who developed the theory of general relativity, and George Lemaître, who proposed the concept of the Big Bang theory based on Friedmann's equations. Their achievements revolutionized our understanding of the cosmos and propelled cosmology into a vibrant field of research.

Interesting Facts

  1. The Friedmann Equation forms the basis of the Lambda-CDM model, which describes the current leading cosmological model of the universe, incorporating dark energy, dark matter, and the cosmic microwave background radiation.
  2. It has been instrumental in confirming the existence of dark energy, a mysterious force responsible for the accelerated expansion of the universe.
  3. The equation has led to significant advancements in our understanding of the early universe, including the inflationary period and the formation of large-scale structures.


The Friedmann Equation plays a vital role in cosmology, providing insights into the expansion and dynamics of the universe. It enables scientists to study the universe's large-scale structure, understand its evolution, and make predictions about its future. Through the work of physicists like Alexander Friedmann, Albert Einstein, and others, our understanding of the cosmos has expanded, and the Friedmann Equation continues to shape our exploration and knowledge of the universe.

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