Convert **knot (kn or kt)** to **light speed (vacuum)**

Selected category: speed.

Knot (kn or kt) is a velocity unit used to express speeds at sea. Knot is equal to 1 nautical mile per hour or 1852 meters per hour.

Speed of light (c) in vacuum is equal to 299 792 458 meters/sec with a relative measurement uncertainty of 4 parts per billion. Up to 17^{th} century humanity wasn't sure if light was transmitted instantaneously or simply very quickly. The Danish astronomer, Ole Christensen Rømer first demonstrated that light travelled at a finite speed when he studied the apparent motion of Jupiter's moon Io.

Swap, do a light speed (vacuum) to knot (kn or kt) conversion.