Solar System in fiction Solar System in fiction The Solar System and its various bodies (planets, asteroids, moons, etc.) were the earliest objects to be treated as fictional locations in works of science fiction. Among these, imaginary voyages to and explorations of Earth's Moon are found in seventeenth century literature. By the early twentieth century, following the increase in scientific and technological development spurred by the Industrial Revolution, fictional journeys to (or from) the Solar System's other planets had become common in fiction. Early literature regarding the Solar System, following scientific speculations dating back to the 17th century, assumed that every planet hosted its
Planet Nine X, Planet Next, or Giant Planet Five." Planet Nine Planet Nine is a hypothetical planet in the outer region of the Solar System. Its gravity could explain the unlikely clustering of orbits for a group of extreme trans-Neptunian objects (eTNOs) that orbit beyond Neptune with average distances greater than 250 AU. These eTNOs tend to have their points of closest approach to the Sun clustered in one direction, and many of their orbits have a similar tilt. This evidence suggests that the gravity from a large undiscovered object is influencing the orbits of the most distant known Solar System objects.