Speed of light with their product equalling "c". In 1983 the metre was defined as "the length of the path travelled by light in vacuum during a time interval of of a second", fixing the value of the speed of light at by definition, as described below. Consequently, accurate measurements of the speed of light yield an accurate realization of the metre rather than an accurate value of "c". Outer space is a convenient setting for measuring the speed of light because of its large scale and nearly perfect vacuum. Typically, one measures the time needed for light to traverse some reference distance
Max Planck Institute for the Science of Light Planck Society. In June 2008, after an evaluation, the senate of the Max Planck Society decided to convert this group to a Max Planck institute and thereupon founded the "Max Planck Institute for the Science of Light" (German "Max-Planck-Institut für die Physik des Lichts"). with effect from January 1, 2009. In 2016, the new building was opened. The project was made by the Munich architecture bureau "Fritsch + Tschaidse Architekten GmbH". Max Planck Institute for the Science of Light The Max Planck Institute for the Science of Light (MPL) performs basic research in optical metrology, optical communication, new optical materials,