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ThuMay 16

International Day of Light – May 16, 2024

International Day of Light is celebrated annually on May 16 to celebrate the contribution of light and light-based technologies to various fields and areas of life, including arts and culture, education, medicine, communications, science, and sustainable development. Did you know that in 1802 Humphrey Davy invented the world’s first electric lamp? International Day of Light commemorates the anniversary of physicist and engineer Theodore Maiman’s first successful laser operation in 1960. The day is observed by the United Nations and administered by UNESCO’s International Basic Science Programme (I.B.S.P.). International Day of Light is celebrated around the world through events and forums organized by people both inside and outside the scientific community.

History of International Day of Light

Since antiquity, humans have used various materials to produce light, ranging from hollow rock, shells, or wood soaked in animal fat and oil lamps to candles and gas. The modern history of light began with the invention of the electric light bulb. Contrary to popular belief, the light bulb was invented long before Thomas Edison patented it. Edison only made it possible for the light bulb to be manufactured commercially. In 1802, Humphrey Davy invented the electric arc lamp, an early predecessor of the incandescent electric bulb, by connecting voltaic piles to charcoal electrodes. However, the arc lamp was not a practical source of lighting as it was too bright for domestic or work uses, and it burned out quickly. This invention led to the creation of the miner’s safety lamp in 1815 and street lighting in several European cities, including Paris, during the 1800s.

In 1850, Joseph Swan solved one of the problems that electric lamp inventors have encountered over the years: the cost-effectiveness of the lamp’s filament. In place of platinum filaments, Swan used cheap carbonized paper filaments. In 1878, he patented his electric lamp in the United Kingdom and demonstrated it at a lecture in Newcastle, England. Swan’s invention, like Davy’s arc lamp, was impractical for everyday use due to the inefficiency of its vacuum pumps. When Edison discovered the flaw in Swan’s electric lamp, he made improvements and presented his light bulb in December 1879. Swan copied these improvements and established an electrical lighting company in England. Edison filed a patent infringement case against Swan, but this failed.

Edison and Swan later formed an alliance called Edison-Swan United, which grew to become the world’s largest light bulb manufacturer. In the early 1960s, Nick Holonyak, an employee at General Electric, accidentally invented the red LED light and patented it for use as a light fixture. In the early 1990s, Japanese and American scientists Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura created the blue LED and were awarded the 2014 Nobel Prize in Physics for it.

Scientists were able to create white LEDs as a result of this. Lighting is becoming more advanced and sophisticated, with the ability to light up homes and streets wirelessly — using smartphones and AI voice commands. Incandescent light bulbs are also being phased out, with halogen, LED, and OLED alternatives taking their place.

International Day of Light timeline

The Electric Arc Lamp

Humphrey Davy invents the electric arc lamp.

The Light Bulb

Edison and Swan patent the first commercially successful bulb.

The Blue LED

Japanese and American scientists Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura invent the blue LED.

21st Century
Wireless Lighting

It’s now possible to switch on or off lighting using AI voice commands and smartphones.

International Day of Light FAQs

Why is International Day of Light celebrated?

International Day of Light is celebrated to raise awareness of the importance of light and light-based technologies to every aspect of human life and leverage it to foster peace and sustainable development.

How far does light travel in a day?

Light travels for 1.609 x 1010 miles in a day — about 86,400 light seconds.

Why was 2015 the Year of Light?

The United Nations made 2015 the International Year of Light because it was a milestone for several innovations and inventions in the history of the science of light.

International Day of Light Activities

  1. Sign the ‘Trust Science’ pledge

    The ‘Trust Science’ pledge is a commitment to following the guidance of science in making crucial decisions. Head to to sign this declaration of confidence in science and encourage your friends to do the same.

  2. Attend an International Day of Light event

    On International Day of Light, many organizations and scientific communities worldwide organize forums, fairs, and other events to commemorate the day. You can check the UNESCO website, Google, or social media for those close to you.

  3. Watch films on lighting

    There are several movies and documentaries about the invention of the light bulb and electricity. One of the most popular ones is “The Current War,” starring Benedict Cumberbatch. Stream it on your favorite streaming service.

5 Fascinating Facts About Light

  1. The speed of light

    Light travels approximately 186,282.4 miles per second in a vacuum and slows when obstructed by the atmosphere.

  2. Humans do glow

    We are bioluminescent, like many other living things, but the light we emit is too weak to be detected by our eyes.

  3. Let there be light

    It took nearly half a million years after the Big Bang for light to reach the Earth.

  4. Light is a wave

    Light has amplitude, wavelength, frequency, and wave speed.

  5. From the Sun to the Earth

    It takes eight minutes and seventeen seconds for light to reach the earth from the Sun’s surface.

Why We Love International Day of Light

  1. Light is crucial to life

    Light is one of the main reasons why life is flourishing on earth. With light, plants grow and produce food for other organisms. Light provides energy that living organisms use to perform all activities. It is also crucial in the production of oxygen and vitamin D necessary by all living organisms.

  2. Light is the key to sustainability

    Light is a crucial source of sustainable energy that humans can leverage to prevent climate change catastrophe. The light produced by the sun is clean, renewable, and has no negative impact on the environment.

  3. Light improves healthcare

    Light-based technologies are employed in healthcare for analysis, imaging, sterilization, genomes sequencing, destroying cancerous cells, and more. These technologies have made it easier to detect and cure diseases, manage global pandemics, and improve healthcare for all.

International Day of Light dates

2024May 16Thursday
2025May 16Friday
2026May 16Saturday
2027May 16Sunday
2028May 16Tuesday

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