Negamass

Negamass is a special form of exotic matter not found in nature that has negative mass. It exhibits very strange properties such as being repelled by normal matter, and accelerating towards any force applied to it instead of in the direction of that force. This can be used as a propulsion mechanism as the center of negative mass will repel the center of positive mass away from it as it is simultaneously pulled towards the positive mass, accelerating infinitely. Its most common uses are in stabilizing the microwormholes of Daedalus ships, stabilizing wormholes that connect the Inhabited Universe, and acting as a core and primary propulsion system of Daedalus ships. It is also occasionally used as a power source and in weaponry, almost exclusively by the Free Persephone Union.

Wormhole Stabilization

Wormholes are fundamentally unstable in nature, tending to be extraordinarily small when they are created and collapsing into nothing within a fraction of a second. When "fed" negative mass they can be prevented from collapsing and even slowly enlarged over time. This is how all planets in the inhabited universe are connected. Older and larger wormholes connecting established economies support a constant flow of high speed transit vehicles between each side, as well as massive communication cables that connect their planets' networks.

Daedalus ships contain small young wormholes called microwormholes. These anomolies are so small that only a slow 2-way stream of data can be supported. While in transit, time slows down for the Daedalus ship relative to a planet bound observer, so that their status messages become further and further apart. These wormholes are enlarged when the ship reaches its destination.

As a Propulsion System

The core of a Daedalus ship is an isolated bundle of negamass such that the sum of the core and the rest of the ship is 0. The core is moved relative to the center of mass of the ship by powerful electromagnets to either accelerate, decelerate, or retain its current velocity. A Daedalus ship only contains enough energy to perform this twice: once to shift its core to a neutral position upon reaching the ship's maximum safe speed, and once upon approaching the ship's destination in order to decelerate.