Orrery on display in Kassel at the Astronomisch-Physikalisches Kabinett and in Dresden at the Mathematisch-Physikalischer Salon. In "De revolutionibus orbium coelestium", published in Nuremberg in 1543, Nicolaus Copernicus challenged the Western teaching of a geocentric universe in which the Sun revolved daily around the Earth. He observed that some Greek philosophers had proposed a heliocentric universe. This simplified the apparent epicyclic motions of the planets, making it feasible to represent the planets' paths as simple circles. This could be modelled by the use of gears. Tycho Brahe's improved instruments made precise observations of the skies (1576–1601), and from these Johannes Kepler
The Wretched of the Earth aspects of the violence and response to violence necessary for total decolonization. He also offers cautions about several different approaches to that violence. In the essay, "On National Culture" published in "The Wretched of the Earth", Fanon sets out to define how a national culture can emerge among the formerly and, at the time of its release in 1961, still-colonized nations of Africa. Rather than depending on an orientalized, fetishized understanding of precolonial history, Fanon argues a national culture should be built on the material resistance of a people against colonial domination. Fanon narrates the essay with reference to what