Science fiction intended as exciting light entertainment. Serious details of physics, astronomy, technology, and character development are de-emphasized in favor of a colorful and fast moving plot. In fact, many such stories contradict or ignore already-known physics (for instance, having space ship engines that run whilst maintaining a constant velocity). Examples are the John Carter on Barsoom (Mars) series by Edgar Rice Burroughs, the Lensman series by E. E. "Doc" Smith, and the Star Wars films.
Many popular science fiction films and television programs may be regarded as space opera. Though many science fiction enthusiasts find confusion between space opera and other forms of science fiction offensive, it is nevertheless the most popular science fiction genre.