Einstein's Greatest Blunder
The 1915 exposition of Einstein's Theory of General Relativity (GR), plus the 1929 empirical statement of Hubble's Law, were the basis of an assumption that both of these applied to the evolution of the Universe. That idea persists to this day. These equations are so appealing, mathematically, that they are also assumed to apply to black holes and to inflation and string theory, even though these solutions are not amenable to experimental confirmation. Einstein admitted that the addition of what he called the "Cosmological Constant" to his tensor set of 10 coupled 2nd order equations, forcing a ststic balance, was his "Greatest Blunder". Actually, his greatest blunder was allowing the scientific community to believe that his GR equations applied to the evolution of the Universe at all!