Element Zero

Element Zero (Atomic Number 0, Chemical Symbol Ez), also known as 'eezo', is a rare material from the Mass Effect Universe that, when subjected to an electrical current, releases dark energy which can be manipulated into a mass effect field, raising or lowering the mass of all objects within that field. A positive current increases mass, a negative current decreases it. This 'mass effect' is used in countless ways, from generating artificial gravity to manufacturing high-strength construction materials. It is most prominently used to enable faster-than-light space travel without causing time dilation.

Generation
Eezo is generated when solid matter, such as a planet, is affected by the energy of a star going supernova. The material is common in the asteroid debris that orbits neutron stars and pulsars. These are dangerous places to mine, requiring extensive use of robotics and shielding to survive the intense radiation from the dead star. Some planets have small eezo deposits or coalesced around a larger deposit during their formation. While these secondary sources are safer to mine, the yield from the ore is not as large.

Other
Dust-form element zero is often released after engine accidents. It is used by many species to influence or strengthen the presence of biotics. If a child is exposed to dust-form element zero in utero, due to its mutagenic effects, there is a small chance they can develop eezo nodules throughout their nervous system that react to electrical stimuli from the brain. This allows them to use biotic abilities, but many exposures have no effect, or result in terminal cancer.

Ships

 * Reapers