Light Speed is the constant rate at which light travels in a vacuum, approximately 3.00x10^8 m/s. While it is theoretically possible with modern technology (and surely the Elder Races had the technology) to accelerate a ship to within a hair of the speed of light, the energy costs necessary to shield a ship moving at any significant fraction of this speed are beyond imagining. A single speck of space dust striking a ship at an appreciable fraction of the speed of light will hit it with the force of multiple nuclear blasts. Instead, most races opt to use skipdrives which utilize wormholes to quickly cover vast distances across time-space in a non-linear fashion.