What is planet science?

In science fiction, a planet killer (also called a "planet buster" in some Sci-Fi circles) is an entity, often a large spaceship or space station, expressly designed to destroy or render uninhabitable a planet (or a dwarf planet). The most famous planet killer is the Death Star from the Star Wars franchise, though many others have been seen on film or print. The science fiction series Babylon 5, Star Trek, Lexx, Farscape, and Stargate SG-1, the tabletop game Warhammer 40,000, as well as the Starflight and Wing Commander computer games all have at least one such device.