Convert Speed of Light (c) to Cosmic Velocity - Third (v₃) instantly.
About these units
Speed of Light (c)
The speed of light in a vacuum, denoted c, is exactly 299,792,458 m/s, one of the most fundamental constants of physics. Light speed defines the structure of spacetime, the upper limit for classical information transfer, and the basis for relativity. Time dilation, length contraction, and mass-energy equivalence (E = mc²) all arise from the invariance of c. In astronomy, the speed of light is used to define light-years, measure cosmic distances, and synchronize observations across telescopes. In communication technology, optical networks rely on light-speed propagation through fiber, albeit slightly slower than in vacuum. c is not just a speed—it is a cornerstone of the physical universe.
Cosmic Velocity - Third (v₃)
The third cosmic velocity is the speed required to escape the entire Solar System from Earth's orbit, overcoming the gravitational pull of the Sun. This speed is approximately 16.7 km/s, though missions often achieve this gradually using gravitational assists rather than brute-force acceleration. Space probes such as Voyager 1, Voyager 2, and New Horizons have exceeded v₃, making them interstellar travelers. The third cosmic velocity represents the threshold where an object ceases to be bound to the Sun and begins drifting through the galaxy—one of the most profound expansions of human technological capability.