Vacuum energy

Vacuum energy is an underlying background energy that exists in space throughout the entire universe. One contribution to the vacuum energy may be from virtual particles, particle pairs throughout the universe that blink into existence and then annihilate in a timespan too short to observe. Their behavior is codified in Heisenberg's energy–time uncertainty principle. The effects of vacuum energy are thought to influence the behavior of the universe on cosmological scales.

In the early 21st century, humanity contemplated the theoretical possibility of using vacuum energy to create free energy machines. It was argued that due to the broken symmetry (in quantum electrodynamics), free energy does not violate conservation of energy, since the laws of thermodynamics only apply to equilibrium systems. While it manifests itself in our universe, vacuum energy originates from the beginnings of infinite numbers of alternate realities. When harnessed for power supply, these fledgling universes are drained of energy in their infancy, resulting in their premature deaths.

Virtually all Forerunner technology utilized the practically infinitely available vacuum energy as a power source, making possible their myriad of technological marvels. These included the Halo Array, as well as the systems used to make their shield worlds, such as Requiem, completely self-sufficient. Forerunner reaction drives utilized vacuum energy to expel virtual neutrons from the rear of the vessel, giving it propulsion.

When designing the MJOLNIR Powered Assault Armor, Dr. Catherine Halsey made a note in her journal to ask Déjà about research on vacuum energy as a potential power source.

List of appearances

 * Halo: Reach
 * Dr. Halsey's personal journal
 * Halo: Cryptum
 * Halo: Silentium
 * Halo: Last Light