- A lithosphere (from Ancient Greek λίθος (líthos) ‘rocky’, and σφαίρα (sphaíra) ‘sphere’) is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy.
- Space opera (Wikipedia)
Space opera is a subgenre of science fiction that emphasizes space warfare, with use of melodramatic, risk-taking space adventures, relationships, and chivalric romance. Set mainly or entirely in outer space, it features technological and social advancements (or lack thereof) in faster-than-light travel, futuristic weapons, and sophisticated technology, on a backdrop of galactic empires and interstellar wars with fictional aliens, often in fictional galaxies. The term does not refer to opera music, but instead originally referred to the melodrama, scope, and formulaic stories of operas, much as used in “horse opera”, a 1930s phrase for a clichéd and formulaic Western film, and “soap opera”, a melodramatic domestic drama. Space operas emerged in the 1930s and continue to be produced in literature, film, comics, television, video games and board games.