The “perfect cosmological principle” describes how a model of the universe should look like. This principle requires the model of the universe to be homogenous (the same everywhere) and isotropic (the same in all directions). Many cosmologists apply this principle to space only, but the universe...

Recently, a group of astronomers recalculated the mass of the Milky Way, with the help of new data from the Gaia and Hubble space telescopes. Until now, different estimates varied from 500 billion to 3 trillion sun-masses, mainly due to the unknown “dark matter” which is supposed to present the...

Contrary to popular believe, there are many Schwarzschild Solutions. Karl himself found one to a mass-point and one to a sphere of in-compressible liquid early 1916. After Karl’s death Einstein made important changes in his  official publication: he abandoned his g = -1 requirement in a footnote. Nobody checked...