Dark matter

Dark matter is a substance shrouded in mystery today; however, in the 31st century, it was widely used as, for instance, star ship fuel. When dark matter prices started to rise due to a supposed shortage, Professor Farnsworth set out to render dark matter useless and to ruin Mom's fortune with the pure anti-backwards energy crystal, which Mom technically stole from Professor Farnsworth along with the metaparticle. The two crystals were destroyed Since the metaparticle was destroyed all dark matter became useless once more.

Description
First speculated in the 20th century, dark matter was a very mysterious subject. The name refers to the only certain property of dark matter: we can't see it. It's existence is only speculated as a result of inconsistencies in our mathematical equations to describe the universe. Some say it doesn't exist at all, others say there is far more dark matter than "regular" matter. By the year year 3000, dark matter has become widely used as a fuel source, particularly for space craft. It was revealed in Bender's Game that dark matter was useless until the professor accidentally created a single non-local metaparticle that links all dark matter and gives its fuelled properties. When the professor accidentally created the metaparticle while smashing dark matter in a particle accelerator he also created a crystal made of pure anti-backwards energy that can destroy the other crystal if they get to close to each other. All dark matter is Nibblonian poo in the form of a ball of no more than one inch in radius can weigh many thousands of pounds.

Dark Matter Engines
Spacecraft fuelled by dark matter were fairly common until 3008, as proven by the availability of dark matter fuel at orbital filling stations. The Planet Express Ship's dark matter engines seem to burn the dark matter in a large furnace, though exactly how this energy is translated into propulsion is understood only by the Professor and his clone, Cubert Farnsworth, as the idea came to them both in a dream, but was forgotten in another dream.

Trivia

 * Conventional methods of Dark Matter mining have not been revealed, but the Planet Express crew found an new source of dark matter - Nibbler. Nibblonians excrete pellets of pure dark matter.
 * One of the few places where Dark Matter has been known to be mined was the planet Vergon 6, now destroyed. It was completely filled with the heavy substance and imploded due to the lack of support for the surface after it was all mined out.
 * Interestingly, Hermes has stated that Nibbler produces so much fuel that the company has to build a new wing to store it. Perhaps this is one of the ways Planet Express funds itself - by selling starship fuel.
 * It is heavily implied, though never directly stated, that it smells something like feces.

Quotes

 * Leela: Dear Captain's Diary: I may not have found love on this mission but I did find a cute little companion who excretes starship fuel. And that's just as good.
 * Bender: Aw man, that crap's heavy! Fry: And warm...