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The Friedmann–Einstein universe is a model of the universe published by Albert Einstein in 1931. The model is of historic significance as the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radius.
- Introduction to Friedmann Cosmology
- An Intuitive Explanation of The Friedmann Equations
- The Continuity Equation in Friedmann Cosmology
- Equations of State
- Solutions of The Friedmann Equations
- What Do The Friedmann Equations Predict?
Now that the James Webb Space Telescope (JWST) is up and running, I want you to imagine that for a day you have control over the telescope. You might be curious to find the first Messier object, the Crab Nebula – the remains of the explosive death of a star, a supernova witnessed on Earth around a thousand years ago. Maybe your astronomical wishes ...
After completing the Herculean task of creating a cosmological spacetime model through the cosmological principle and the FRW metric, let’s see what we can learn from it and how the Friedmann equations come about from it! Without further ado, here are theFriedmann equations: Let’s begin breaking these down! Below, you’ll find an explanation for eac...
In the Friedmann model of cosmology, we use aperfect fluid with density and pressure(which both appear in the Friedmann equations) to model the matter, radiation and energy content in the universe on cosmic scales, as mentioned previously. This perfect fluid assumption allows us to encapsulate the cosmological principle. We’ll talk about how we dis...
Equations of state are a crucial part whenever we’re working with the Friedmann equations. In fact, we cannot really obtain any useful solutions or predictions from the Friedmann equations without an equation of state. An equation of state simply tells us how different variables are related to each other – in our case this would be energy density a...
Before we look at what the Friedmann equations actually predict about our own universe, let’s look back at the bigger picture. The most important equations we’ve discovered so far can be summarized as the following:
In this section, we will consider how the Friedmann equations can be used to predict various things about our own universe, such as the eras of our universe’s history, the age of our universeand so on. We’ll also consider the interesting question of how our universe might end as well(at least how the Friedmann equations would predict) as well as ho...
The Friedmann equations, also known as the Friedmann-Lemaître or FL equations, are a set of equations in physical cosmology that govern the expansion of space in homogeneous and isotropic models of the universe within the context of general relativity.
Friedmann universe, model universe developed in 1922 by the Russian meteorologist and mathematician Aleksandr Friedmann (1888–1925). He believed that Albert Einstein’s general theory of relativity required a theory of the universe in motion, as opposed to the static universe that scientists until.
- The Editors of Encyclopaedia Britannica
Le equazioni di Fridmann sono un insieme di equazioni in cosmologia fisica che governano l'espansione dello spazio in modelli omogenei e isotropi dell'universo nel contesto della relatività generale. Sono state derivate per la prima volta da Aleksandr Fridman nel 1922 dall'equazione di campo di Einstein della gravità nella metrica ...
The Einstein–de Sitter universe became a standard model of the universe for many years because of its simplicity and because of a lack of empirical evidence for either spatial curvature or a cosmological constant.
General relativity can tell us physically what factors relate to the expansion. One version of the Einstein equations is the Friedmann equation, which describes how the expansion rate changes over time, and why, in a homogeneous and isotropic Universe.
