# What does the Friedmann equation say?

## What does the Friedmann equation say?

The Friedmann equation which models the expanding universe has a parameter k called the curvature parameter which is indicative of the rate of expansion and whether or not that expansion rate is increasing or decreasing. It indicates the future fate of the universe.

## How is the Friedmann equation used to determine the age of the universe?

The Friedmann equation includes the Hubble constant to give a much more accurate age of the universe. In this equation, G is the gravitational constant = 6.67*10-11Nm2/kg2, ρr is the radiation density of the universe, ρm is the matter density of the universe, and ρd is the dark energy density of the universe.

What is the closed universe theory?

(in cosmology) a hypothetical expanding universe that contains sufficient matter to reverse the observed expansion through its gravitational contraction.

### What did Alexander Friedmann discover?

Ninety years ago, Russian physicist Alexander Friedmann (1888–1925) demonstrated for the first time that Albert Einstein’s general theory of relativity (GR) admits nonstatic solutions. It can, he found, describe a cosmos that expands, contracts, collapses, and might even have been born in a singularity.

### What is the most famous equation ever?

E=mc²
Einstein’s E=mc² is the world’s most famous equation. Simple as that. It is short, it is elegant, and it describes a phenomenon so crucial that everyone should know about it.

What is the formula of universe?

The formula toc=h/moc expresses the electro-gravitational field bound to M2VP . Protons ( M2VP ) represent the stable particles of matter of the expanding universe. They move in every given direction at a speed less than c. By uniting E=moc2 of the relativity with E=hv of the quantum theory, we obtain toc=h/moc .

#### Is our universe de Sitter?

The early universe was radiation-dominated, because radiation has an exponent of −4, which is the biggest. Our universe is currently quite well approximated by de Sitter space.

#### What is the density of matter in the universe?

The expansion rate we see today indicates that the critical density of the Universe is about 9×10-27 kg m-3. This density, however, is the total density of both matter and energy.

What are the 4 models of the universe?

3.1 A geocentric universe

• 1 Eudoxus and a geocentric universe.
• 2 Aristotle and a finite, eternal, and geocentric universe.
• 3 Aristarchus and the distance to the Sun and Moon.
• 4 Eratosthenes and the circumference of the Earth.
• 5 Ptolemy and epicycles.

## What are the 3 alternative models of the universe?

Three Models of the Universe: Flat, Open & Closed.

## Who proposed oscillating universe theory?

Einstein first proposed this theory in the 1920’s in response to the model of the expanding universe.

What is the Friedmann model of the universe?

2 Answers 2. The “Friedmann model” is a model of the Universe governed by the Friedmann equations, which describes how the Universe expands or contracts. These equations are a solution to Einstein’s field equations, and with two very important assumptions they form the basis for our understanding of the evolution and structure of our Universe.

### Which is an example of a Friedmann model?

And also give some examples of Friedmann models, specially I would like to know if the lambda-CDM model is considered a Friedmann model. The “Friedmann model” is a model of the Universe governed by the Friedmann equations, which describes how the Universe expands or contracts.

### What are the equations of the Friedmann Robertson Walker universe?

a = − 4πG 3 ) ρ+ 3p c2 * + Λ 3 (4.10) where the ﬁrst equation is from the 00 component of the Einstein equations and the second is from theiicomponent. These are theFriedmann Equations.Thenicething is that after all the hard work we obtain, ﬁnally, a very simplesetofordinarydiﬀeren- tial equations.

What are the consequences of the Friedmann equation?

For now, to explore some consequences of the Friedmann equation, we assume ρ ∝ a − 3. This is a model that most cosmologists, over 25 years ago, thought was probably an excellent approximation to reality. With this assumption, there becomes a connection between the geometry of space, and the fate of the universe.