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`H_0 = sqrt(kappa * rho /3)`

Enter a value for all fields

The **Hubble Constant** calculator computes the Hubble Constant based on the mean density of matter in the universe and Einstein's Constant.

**INSTRUCTIONS:** Choose units and enter the following:

- (
**ρ**) Mean density of matter in the universe

**Hubble Constant(H _{0}):** The calculator returns the constant in seconds per meter square.

The Hubble Constant is the the constant of proportionality between the "proper distance" *D* to a galaxy and its velocity *v.*

In the Einstein-de Sitter model, Einstein and de Sitter derived a simple relation between the average density of matter in the universe and its expansion according to *H _{0}^{2}= κ⋅ρ/3*. If one solves for H

H_{0} = `sqrt(κ * ρ /3)`

where:

- H
_{0}is the Hubble constant - ρ is the average density of matter in the universe
- κ is the Einstein's Constant

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. It also represented an important theoretical case of a universe of critical matter density poised between contraction or expansion at an ever-increasing rate.

In Einstein’s later analysis of cosmology, Einstein depicted the Einstein–de Sitter model as only one of several possibilities for the expanding universe.

The Einstein–de Sitter universe was particularly popular in the 1980s, after the theory of cosmic inflation predicted that the curvature of the universe should be very close to zero. This case with zero cosmological constant implies the Einstein-de Sitter model, and the theory of cold dark matter was developed, initially with a cosmic matter budget around 95% cold dark matter and 5% baryons. However, in the 1990s various observations including galaxy clustering and measurements of the Hubble constant led to increasingly serious problems for this model. Following the discovery of the accelerating universe in 1998, and observations of the cosmic microwave background and galaxy redshift surveys in 2000-2003, it is now generally accepted that dark energy makes up around 70 percent of the present energy density while cold dark matter contributes around 25 percent, as in the modern Lambda-CDM model.

The Einstein-de Sitter model remains a good approximation to our universe in the past at redshifts between around 300 and 2, i.e. well after the radiation-dominated era but before dark energy became important.

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