The theme of "The Night of Light" is "Dark and Light", a walk around dark matter and dark energy, highlighting the key role of light in exploring this dark part of our Universe. This event is scheduled simultaneously and in duplex in several cities in France: Massy, Marseille and Grenoble.

Experts from the CEA/AIM Astrophysics Department and the Orsay Institute of Space Astrophysics are offering an immersive and interactive exhibition on the theme of light at the Cité des Sciences et de l'Industrie from March 17 to August 30, 2015. Conceived as part of the Year of Light, this exhibition offers visitors the opportunity to follow the journey of two particles of light, each taking different paths within the Universe. Each journey has five main stages, revealing common physical processes at the scale of the Universe and at the scale of the stars.

This mediation device aims to facilitate the appropriation by the greatest number (high school students, students, teachers, general public) of the electromagnetic spectrum: wavelength, frequency, photon energy. The associated website, interactive and educational, will present the experiments that study these different "lights" as well as the associated applications - from science to everyday life.