History of Poland during the Jagiellonian dynasty major towns. Polish science reached its culmination in the first half of the 16th century, in which the medieval point of view was criticized and more rational explanations were formulated. Copernicus' "De revolutionibus orbium coelestium", published in Nuremberg in 1543, shook up the traditional value system extended into an understanding of the physical universe, doing away with its Christianity-adopted Ptolemaic anthropocentric model and setting free the explosion of scientific inquiry. Generally the prominent scientists of the period resided in many different regions of the country, and increasingly, the majority were of urban, rather than noble origin. Nicolaus Copernicus, a son
Age of the Earth it would take for the near-surface to cool to its present temperature. His calculations did not account for heat produced via radioactive decay (a process then unknown to science) or, more significantly, convection inside the Earth, which allows more heat to escape from the interior to warm rocks near the surface. Even more constraining were Kelvin's estimates of the age of the Sun, which were based on estimates of its thermal output and a theory that the Sun obtains its energy from gravitational collapse; Kelvin estimated that the Sun is about 20 million years old. Geologists such as Charles Lyell