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RUTA

Science Advisor

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## Main Question or Discussion Point

Continue reading...In Part 1 of this 3-part series, I explained kinematics in Einstien-deSitter (EdS) cosmology and in Part 2, I explained kinematics in ##\Lambda##CDM cosmology (essentially EdS plus a cosmological constant ##\Lambda##). Now I will bring those models to bear on the Supernova Cosmology Project (SCP) Union2.1 type Ia supernova data. This will show clearly how the EdS fit of the supernova data is greatly improved by adding ##\Lambda## to Einstein’s equations (EEs) of general relativity (GR). This fact convinced the astronomy community that a cosmological constant is indeed needed in EEs. This cosmological constant ##\Lambda## is often referred to as “dark energy,” as I explained in Part 2. I’ll start by explaining the concept of “distance modulus.”...