In our ongoing series on Light and light-based objects, scientist Dr. V. B. Kartha says that life not only emerged from light but is also perceived and understood through light.
LIGHT is a form of energy that helps us see the world around us. Most living organisms need light to see. Man has always been fascinated by light – what it is made of, how it was formed, when, etc.
It is now accepted that the Universe originated from a “Big Bang” some 13.8 billion years ago. The Big Bang happened when a single point in the cosmos, which is referred to as the ‘primordial egg’, either exploded or expanded, releasing huge amounts of energy at extremely high temperature and pressure.
The energy that was spewed out by the Big Bang was in the form of ‘light photons’ or particles of light. Because of the high energy that each particle carried, they travelled in all directions at tremendous speed.
As the expanding explosion cooled down, energy in the form of photons started getting converted into subatomic particles namely electrons, protons and neutrons. These particles gave birth to simple atoms like hydrogen, helium and lithium.
Meanwhile, the cooling of particles continued and bigger atoms came into existence. Energy was converted to matter. When matter was born, gravity started playing its role, and matter started coming together to form stars and planets. The Universe as we know today started taking shape.
Around 10 to 17 million years ago, simple molecules like nitrogen oxide (NO), carbon monoxide (CO), water (H2O), etc got formed. This was followed by formation of bigger molecules like amino acids, sugars, and later still bigger molecules like proteins, carbohydrates and DNA, and the process of the evolution of life began. The various steps in evolution, from empty space to particles to simple atoms and molecules, molecular assemblies, cells and large, multicellular organisms have their origin in light. In short, life comes from light.
Today we know that light is electromagnetic radiation consisting of aves of electric and magnetic fields. Light has an incredible speed of 300,000,000 metres per second in vacuum. This is the absolute boundary for motion. Nothing in the Universe can move faster than light. Though light is said to travel in the form of waves, the big bang theory tells us that light is particulate in nature (made up of particles). Newton also talked about the ‘particles of light’ (corpuscular theory), but at the time, certain properties of light could not be explained by this theory and hence, the wave theory of light continued to hold good. Today, light is seen in the form of waves as well as particles.
We understand the world around us through our eyes with the help of light. When our eyes are not sufficient, we use instruments that use light as the probe. The life that emerged from light is perceived and understood through light.