The speed of light, also referred to as light speed, or the warp threshold, is the velocity that light travels in a vacuum. This constant, usually denoted c, is exactly 299,792,458 meters/second or 186,282 miles per second. The speed of light was equivalent to the speed of warp factor 1. (ENT: "First Flight", display graphic) Outside of subspace, no known natural phenomena can move faster than the speed of light. (TOS: "The Lights of Zetar")
The ability to travel faster than light was considered to be a major technological milestone in a species' development. The United Federation of Planets typically subdivided civilizations and cultures on whether they had developed technology to exceed the speed of light. The species that had not yet achieved the level of technology required were placed in the pre-warp civilization category. The Vulcan custom of not making first contact with pre-warp civilizations was later on adopted by the Federation as well. (ENT: "Civilization"; TNG: "First Contact")
In 2254, the USS Enterprise encountered a faked distress call from SS Columbia created by the Talosians. The signal was keyed to register on sensors as an unknown object on a collision course which traveled with the speed of light. (TOS: "The Cage")
- See: Propulsion
According to Star Trek: The Next Generation Technical Manual, (pp. 54 & 55) in the context of a warp drive, under the conditions where the total amount of subspace distortion in all the energy layers put together, that form a warp field around a ship, equal 1 cochrane and this accelerates the ship to the speed of warp factor 1, or the speed of light, approximately 20 gigajoules of energy are required to create the warp field, and only 200 megajoules to maintain it. Depending on a multitude of spatial conditions, the level of cochranes required for any given warp factor varies.