The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.

Very popular Animutation flash video. Suprisingly, as opposed to most other Animutation videos, the lyrics are in English, but they're sung with a heavy Japanese accent, which makes them hard to understand. The subtitles say what the words sound like, which is often quite hillarious. The song is "The Hot Limit" by Dance Dance Revolution.