The study of light has led to promising alternative energy sources, lifesaving medical advances in diagnostics technology and treatments, light-speed internet and many other discoveries that have revolutionized society and shaped our understanding of the universe. These technologies were developed through centuries of fundamental research on the properties of light – starting with Ibn Al-Haytham’s seminal work, Kitab al-Manazir (Book of Optics), published in 1015 and including Einstein’s work at the beginning of the 20th century, which changed the way we think about time and light.

Asia's First Sustainable Light Art Festival at Marina Bay - Singapore

The International Day of Light celebrates the role light plays in science, culture and art, education, and sustainable development, and in fields as diverse as medicine, communications, and energy. The celebration will allow many different sectors of society worldwide to participate in activities that demonstrates how science, technology, art and culture can help achieve the goals of UNESCO – building the foundation for peaceful societies.

Why light matters

Light and Development
Light, Science and Technology
Light, Education and Culture
Light is life. Without light, life on our planet would not exist. In studying light through astrophysics, we delve into some of the deepest mysteries of the universe. In exploring optics and quantum optics, we plunge into the heart of matter itself .
Shamila Nair-Bedouelle - Assistant Director-General for Natural Sciences, on the occasion of the International Day of Light 2020

The message of the International Day of Light 2021 — Trust Science — encourages both scientists and the public alike to sign and support a declaration affirming their trust in science and the importance of public confidence in the scientific process. Now is the time for us all to pledge our support.
We ask all supporters of the International Day of Light and its objectives to join with us in signing the Trust Science Pledge. This includes those who support the crucial role of the scientific process in improving our quality of life.