- Apocalyptic and post-apocalyptic fiction is a subgenre of science fiction in which the Earth’s (or another planet’s) civilization is collapsing or has collapsed. The apocalypse event may be climatic, such as runaway climate change; astronomical, an impact event; destructive, nuclear holocaust or resource depletion; medical, a pandemic, whether natural or human-caused; end time, such as the Last Judgment, Second Coming or Ragnarök; or any other scenario in which the outcome is apocalyptic, such as a zombie apocalypse, cybernetic revolt, technological singularity, dysgenics or alien invasion.
- Moon (Wikipedia)
The Moon is Earth’s only natural satellite. Its diameter is about one-quarter of Earth’s (comparable to the width of Australia), making it the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet. It is larger than all known dwarf planets in the Solar System. The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth’s at 0.1654 g—Jupiter’s moon Io is the only satellite in the Solar System known to have a higher surface gravity and density.