Light – smallest yet the mightiest


Science knows no country because it is the light that illuminated the world- Louis Pasteur

The International Day of Light is celebrated on May 16th every year, the anniversary of the first successful operation of the laser in 1960 by famous physicist and engineer, Theodore Maiman. The laser, as we all know is a perfect example of how a scientific discovery can give revolutionary benefits in communications, healthcare and many other fields. Simplest of things can make the greatest impacts.

From early attempts to understand the path of stars and planets to the appreciation of the importance of light in processes like photosynthesis, human has made efforts to understand the nature and the characteristics of light and that has revolutionized nearly every field of science.

A significant stage of the evolution of the Universe occurred around 300,000 years after the Big Bang when the temperature was suitable and cool enough (around 4000 degrees) for neutral atoms to form. Before that time, there were too many charged particles to allow light to travel more than a short distance.  After atoms were formed, light could travel large distances. In fact, we can receive today ‘light’ (in the form of microwaves) that has been traveling for over 13 billion years.

Formation of the Sun and the solar system was of more importance to us – including our planet – about 4.5 billion years ago. Earth has been showered with light from the Sun ever since. It is our most important and abundant source of energy. Sunlight warms us, causes crazy weather patterns, makes plants to manufacture oxygen and our food from carbon dioxide and water, and it allows us to find our way around in the daytime!

Over two billion years ago, the use of sunlight in photosynthesis, to make oxygen and carbohydrates from carbon dioxide and water, is a process first established by cyanobacteria. They made the large quantities of oxygen in the atmosphere which made oxygen-breathing life to evolve. Today plants use chlorophyll to achieve the exact same result, keeping the atmosphere breathable, and providing food energy for us and all other life forms.

Of course, mankind has found or transformed other sources of light over the course of history. Fire is obviously the earliest of these: from the campfires of our cave ancestors to the oil lamps still used where there is no electricity. But electricity is the source of artificial or transformed light today, starting with the invention of the incandescent light by Joseph Swan and Thomas Edison and evolving via fluorescent lighting to modern LED lights.

Human has also learned to control light. The use of mirrors and lenses to deviate light, or to magnify images, dates from pre-history. Microscopes and telescopes, using mirrors or lenses are two closely related inventions from just a few hundred years ago. They allow us to study objects smaller than our naked eyes can see (microbes), and objects at large distances (planets, stars), whether ships at sea, or astronomical bodies at enormous distances.

We can also send light from one place to another using optical fibers or ‘light guides’ which has revolutionized modern day communication. These allow us to use light to transmit large amounts of information and to explore regions where we cannot go, such as in medical probes or endoscopes and other medical purposes.

From minute to astronomical standards light has been our saviour.

Timeline of the history of light

The sun – 4 Billion BCE
The fire 400,000 BCE
Torch 400,000 BCE
Primitive lamp 13,000 BCE
The candle – 400 BCE
Kerosene lamp – 1853
Edison bulb – 1879
Neon lamp – 1898
Gas-filled lamp -1913
Fiber optics – 1955
The laser – 1960
LED – 1999

16th May 2018 was the inaugural International Day of Light (IDL) – an annual, global initiative that provides an appreciation of light. IDL aims to raise awareness of the critical role light-based technologies play in our lives, elevating science, technology, art, and culture to help achieve the goals of UNESCO – education, equality, and peace.

Goals of the International Day of Light are:

  • Improve the layman’s understanding of how light and light-related technologies touch the daily lives of everybody and are central to the development of the global society.
  • Build worldwide educational capacity through activities targeted on science for young people, addressing issues like gender balance, and focusing especially on developing countries like India and emerging economies.

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