Supernova Cosmology Project

The Supernova Cosmology Project ( SCP short ) was an astrophysical research project that was conducted in the 1990s by researchers from various international institutes led by Saul Perlmutter. The objective of the SCP, and another, of which independent project (High -z Supernova Search, short high- z SS, z for redshift ) to measure the expansion rate of the universe was.

Result

Result of the SCP (as well as the High -z SS) was the discovery of the acceleration of the cosmic expansion. The reason for the expansion is not understood today and is generally described by the term " dark energy ". In the equations of general relativity, the accelerated expansion expresses the fact that the cosmological constant is positive. In addition, the relative matter energy density using the data of the SCP and the relative vacuum energy density ( dark energy ) to determined.

Methodology

In SCP Searched for distant supernovae of type Ia, which had a redshift z > 0.1. For each supernova each have their redshift z was their apparent brightness as well as their absolute brightness measured; latter can be determined in supernovae of this type by observing the light curve. The distance d of each supernova was determined by comparison of the absolute with the apparent brightness.

This gave a dependence d ( z) which is not a straight line and thus differs from the Hubble law with a constant Hubble parameter: at a given redshift z, the distance d is larger than expected and at a given distance, the redshift z d is smaller than expected. It follows that the expansion ratio ( for the z dimension a ) in the past ( that is, for large D ) was small, representing an accelerated expansion.

Appreciation

The results were published by the staff of the SCP and the High -z SS 1998. In the same year, the two collaborations annually allocated by the journal Science Award "Breakthrough of the Year" received ( German: Breakthrough of the Year ) and the 2007 Gruber Prize for Cosmology and 2011 Nobel Prize for Physics.