The origin of our species dates back to about 300 thousand years, a relatively short period compared to the 4.5 billion years of our Earth’s geologic history. Through the millennia, mankind has evolved to become the dominant species on the planet. Apart from our complex brains that are the most advanced among animals, we are gifted with curiosity to discover the wonders of the world we live in which is arguably one of mankind’s greater purposes.
Our advancement can be attributed to our desire to learn and our inherent, perpetual curiosity. Learning follows observation, which then leads to inferences about a phenomenon. Observations are made through our senses, predominantly through our eyes.
But the human eye can only perceive so much. What we see through it wasn’t by any means going to quench man’s unquenchable thirst for knowledge. To expand our field of view of the universe and its mysteries, we invented something simple yet almost magically marvelous – the lens.
Looking back in time: the history of lenses
The earliest historical evidence of a lens dates back as far as the 7th Century BC. Called the Nimrud lens, the slightly oval rock crystal was unearthed from an Assyrian palace and is thought to have been used as a magnifying glass or a burning glass to help start fires. The Ancient Greek and Roman mathematicians began experimenting with lenses and began building the foundations of classical optics. The pivotal breakthrough in the history of lenses took place at around 1200 AD when Chinese and Italian inventors created the first spectacles to be used to correct vision.
Shedding light on lenses: How lenses work
The beauty of lenses lies in their surprising simplicity. Every lens – whether it be the ones in your eyes that are focusing the images of these words you are reading right now to the retina of your eye, to the many lenses in a compound microscope – is more or less a transparent material with two surfaces that help focus light rays from an object to form an image. Lenses are of two types: convex and concave. Lenses that have thicker centers than edges are convex while concave lenses have thicker edges than centers.
Lenses function on the principles of refraction. The curved surfaces of a lens allow different incident light rays to bend at different angles. The images formed as a result can be real or virtual depending on whether the image can be visualized on a screen or not.
In fields that demand precision such as astronomy and microscopy, single lenses are incapable of producing images that can be worked with due to the imperfections called aberrations. Therefore, multiple lenses are used to assemble devices such as microscopes, telescopes, and cameras.
Making the invisible, visible: Telescopes and Microscopes
The greatest contribution provided by the invention of lenses was when people discovered that they could be used to observe both enormous objects situated afar, and minute objects situated nearby. The former could be accomplished by the use of telescopes while the latter through microscopes.
The first microscope was invented by Zacharias Janssen, a Dutch eyeglass maker in 1590. Ever since then, microscopes have been developed, with significant improvements to their magnification and resolutions and a reduction in their limitations. This invention enables thousands of novel discoveries every year from identifying new microorganisms, developing novel life-saving drugs, investigating forensic evidence, and identification of diseases and is even used in paleontology. The implications and impacts of this invention have changed the course of human history in unimaginable ways.
The microscope revolutionized the scientific field by paving the way for the introduction of revolutionary theories in science such as the Cell Theory which laid the foundations for the study of life. From school science laboratories to state-of-the-art research facilities worldwide, the microscope is an indispensable instrument in almost all modern-day laboratories.
Microscopes have been developed to reveal the structures of cells and tissues at unprecedented levels of detail, exposing the many secrets that lie hidden and answering questions that may have bothered us for centuries.
The other game-changing instrument is the telescope. The telescope was the brainchild of Hans Lippershey, another Dutch eyeglass maker and a contemporary of Janssen, and was invented in 1608. However, the telescope’s current uses were popularized by Galileo Galilei. He directed his own improved telescope to the heavens and was able to observe the craters of the moon, four of Jupiter’s many moons, and even sunspots. Similar to microscopes, telescopes underwent drastic changes to become what they are today, allowing us to observe the night sky like never before.
Capturing light, preserving time: Cameras
Saving fleeting moments of our lives and the world around us and preserving its beauty became a reality since the invention of the camera. The earliest camera was called a camera obscura and has its history tracing back to the Middle Ages and was mostly used to study eclipses. The earliest forms used a pinhole-sized opening on the wall of a dark chamber that allows light to enter thereby projecting an image.
The first modern-day camera was invented by a French inventor named Nicéphore Niépce in 1827. His technology allowed an image to be captured onto pewter plates coated with asphalt. This invention was further developed by Louis Daguerre in 1839 and replaced pewter plates with silver-plated copper sheets coated in iodine which significantly reduced the exposure time.
Through the years that followed, cameras underwent significant alterations and ultimately made the giant leap to digital camera technology in the 1980s.
To see is to believe
Lenses, undoubtedly, have been instrumental in creating countless scientific success stories, Simultaneously, they have been sharpening our focus in observing what lies beneath nature’s intricate veneer and broadening our scope to usher in novel ideas helping us see beyond the horizons of our current knowledge.
In a more literal sense, lenses have and continue to aid millions of people to see the world clearly by helping to correct various visual defects. This was perhaps their purpose in the days of old and has become its most popular use today.
Lenses go back a long way, and they continue to serve humanity in many ways than one, opening our eyes to see a bigger world and making us believe that there will always be more to see.
By Rtr. Yowan Dias
References:
- A brief history of the lens – OpenLearn – Open University
- history of photography | History, Inventions, Artists, & Events | Britannica
- optics | History, Applications, & Facts | Britannica
- lens | Meaning, Principles, Manufacture, & Facts | Britannica
- History of Microscopes
- Who Invented the Telescope? | Space
- The Invention of the Camera (automate.org)
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Beautifully written Yowan! 🤩❤ Keep up the good work!