Light plays a crucial role in people’s lives. For plants it is the origin of life itself, through photosynthesis. It is also essential in fields of study that are as diverse as medicine, communication, and energy.
The International Day of Light has been held on May 16th since 1960, celebrating the role light has played in science, art and culture, education, and sustainable development. The date was chosen to commemorate the unveiling of history’s first laser beam, the brainchild of physicist and engineer, Theodore Maiman.
We are observing this date with a compilation of four great moments in science that advanced the study and our understanding of light.
The Faraday effect
British physicist and chemist, Michael Faraday, made fundamental contributions to the electromagnetic theory of light. In 1845, he discovered that a magnetic field influences a beam of polarized light, a phenomenon now known as the Faraday effect or magneto-optic effect. It was the first demonstrative experimental evidence that light and magnetism are related.
The following year, Faraday published the article ‘Thoughts on Ray Vibrations,’ which proved to be prophetic as it speculated that light is a type of vibration of electric and magnetic lines of force.
The Maxwell equations
Scottish scientist, James Clerk Maxwell, developed the classical theory of electromagnetic radiation, which serves as the theoretical basis defining the relationship between light and magnetism, which was first experimentally proven by Faraday.
Maxwell’s equations showed that if electricity and magnetism are two sides of the same coin, light is the coin in movement. These equations consolidated knowledge obtained from the results of the already mentioned Faraday experiments, but also incorporated those of Coulomb, Gauss, Ampere, and others. The equations were a key discovery for modern physics and a source of inspiration for the great 20th-century physicists.
In 1953, the Indian physicist Narinder Singh Kapany designed and built a glass cable capable of transporting light, which was later called fiber optics, an invention that would prove indispensable for the Internet and telecommunications.
This genius in the field of physics has lived to see how his work has revolutionized the world. Today, 95 percent of Internet traffic travels through thick undersea cables consisting of optical fibers. This material has also made great advances in other disciplines possible — for example in medicine, with cutting-edge biomedical instrumentation, or energy, with efficient solar energy systems.
The future: artificial photosynthesis
For decades human beings have dreamed of being able to replicate the best kept secret of plants: their ability to trap solar energy. Achieving artificial photosynthesis is a futuristic dream that could be a key to sustainable energy. It is far removed from the conventional solar energy of today, which has significant storage problems. Batteries do not have infinite capacity, and in places like Norway or Sweden where the summer has ten times more light than the winter, it is impossible to store six-months worth of energy to be used during the other half of the year.
So far, several experiments have yielded promising results. For example, in 2011 a team at Harvard University created artificial leaves out of thin sheets of silicon that used artificial photosynthesis, harnessing solar energy to break water molecules, which in turn produced oxygen and hydrogen. Hydrogen is used today as a fuel for electric cars, so this could be a window to the future for sustainable transportation.
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