Denmark the 22 proposals have been agreed upon by a parliamentary majority. Denmark shares strong cultural and historic ties with its Scandinavian neighbours Sweden and Norway. It has historically been one of the most socially progressive cultures in the world. In 1969, Denmark was the first country to legalise pornography, and in 2012, Denmark replaced its "registered partnership" laws, which it had been the first country to introduce in 1989, with gender-neutral marriage. Modesty and social equality are important parts of Danish culture. The astronomical discoveries of Tycho Brahe (1546–1601), Ludwig A. Colding's (1815–88) neglected articulation of the principle of conservation
Stellar isochrone Stellar isochrone In stellar evolution, an isochrone is a curve on the Hertzsprung-Russell diagram, representing a population of stars of the same age. The Hertzsprung-Russell diagram plots a star’s luminosity against its temperature, or equivalently, its color. Stars change their positions on the HR diagram throughout their life. Newborn stars of low or intermediate mass are born cold but extremely luminous. They contract and dim along the Hayashi track, decreasing in luminosity but staying at roughly the same temperature, until reaching the main sequence directly or by passing through the Henyey track. Stars evolve relatively slowly along the main sequence