Selected category: speed.
Selected initial unit : light speed (vacuum).
Definition and details for light speed (vacuum):
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 17th 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.
Convert light speed (vacuum) to :