Light is the most powerful form of energy and is our life force. The greatest source of light originates from the sun. The world is a dark and dead place without sunlight. The biological clocks of all living things on earth revolve around the day and night cycle brought about by the sun.
Unlike other forms of energy such as heat and sound, light does not require a medium for transmission. The sun’s light travels through the vacuum of space and the earth’s atmosphere before reaching the earth. Light travels at the fastest speed, around 671 million miles per hour!
Light benefits the earth in three fundamental ways – life, heat and colors. Without light, plants cannot photosynthesize and grow. Then all animals and fish that depend on plants for survival will die. Light is also the original source of fossil fuels which are derived from dead plants buried underground for millions of years. Light is readily converted to heat energy. You can demonstrate this by focusing sunlight with a magnifying glass on a piece of paper. It will cause the paper to burn. Without sunlight that heats up the land and ocean creating a temperature gradient, there will not be wind or current flows. Finally, sunlight consists of different colors as seen in a rainbow caused by reflection and refraction due to water droplets in the air.
Humans have learned to make artificial light. The ancient way is making a fire. Modern artificial light involves passing electricity through a metallic filament (incandescent), a gas (fluorescent) or an electronic device (LED).
We have also learned to make energy on a large scale from sunlight. Wind energy is indirectly derived from sunlight that creates airflow through a temperature gradient from one area to another. Solar energy is direct conversion of sunlight to electricity through photovoltaic cells. The most powerful form of artificial light is laser that is increasingly used for industrial and medical purposes.
Have you wondered why the information on the Internet flows so fast around the world? They use light to carry the information through optical fibers laid under the sea or underground.