1421 Esperanto in the outer asteroid belt at a distance of 2.8–3.4 AU once every 5 years and 5 months (1,983 days; semi-major axis of 3.09 AU). Its orbit has an eccentricity of 0.08 and an inclination of 10° with respect to the ecliptic. The body's observation arc begins with its first observation as at Heidelberg Observatory in October 1906, almost 30 years prior to its official discovery observation at Turku. This minor planet was named by the discoverer after the artificial language, Esperanto, which was created by inventor and writer, Ludwik Lejzer Zamenhof (1859–1917), who used the pseudonym "Doktoro Esperanto". The
Ludwik Silberstein structures ("struts", "ropes", or "membranes") that are responsible for holding masses against the attractive force of gravity in a static configuration. According to Martin Claussen, Ludwik Silberstein initiated a line of thought involving eddy currents in the atmosphere, or fluids generally. He says that Silberstein anticipated foundational work by Vilhelm Bjerknes (1862 – 1951). Ludwik Silberstein Ludwik Silberstein (1872 – 1948) was a Polish-American physicist who helped make special relativity and general relativity staples of university coursework. His textbook "The Theory of Relativity" was published by Macmillan in 1914 with a second edition, expanded to include general relativity, in 1924.