Indigenous Aryans were inter-related, and the notion of biological race came to the forefront The "Aryan race," the presumed identity of Indo-European language speakers was prominent among such races, which was seen to be further subdivided into "European Aryans" and "Asian Aryans," each with their own homelands. Max Mueller, who translated the Rigveda during 1849–1874, postulated an original homeland for all Aryans in central Asia, from where a northern branch was believed to have migrated to Europe and a southern branch came to India and Iran. The Aryans were fair-complexioned Indo-European speakers who conquered the dark-skinned "dasas" of India. The upper castes,
Laser propulsion laser electric propulsion, using magnetohydrodynamics to convert laser energy to electricity and to electrically accelerate air around a vehicle for thrust. Laser propulsion Laser propulsion is a form of beam-powered propulsion where the energy source is a remote (usually ground-based) laser system and separate from the reaction mass. This form of propulsion differs from a conventional chemical rocket where both energy and reaction mass come from the solid or liquid propellants carried on board the vehicle. The basic concepts underlying a photon-propelled "sail" propulsion system were developed by Eugene Sanger and the Hungarian physicist György Marx. Propulsion concepts using laser-energized