Change in world is inevitable—and in some cases, essential for the evolution of animal species. Some changes occur naturally, while others emerge through scientific discovery. DNA, gravity, and the germ theory of disease are among the most transformative discoveries in history, permanently altering the course of human civilization. Discover Magazine has highlighted ten such scientific breakthroughs that have profoundly shaped the modern world. Let us delve into the stories behind these discoveries.
DNA
DNA is the molecule that carries the genetic information of living organisms. It plays a critical role in determining how traits from parents are inherited by their offspring. DNA is the primary component of chromosomes.
Although many believe that scientists James Watson and Francis Crick discovered DNA in the 1950s, the truth is that Swiss physician Friedrich Miescher first identified the molecule in 1869. He discovered it in the nuclei of white blood cells and named it “nuclein.” Prior to Watson and Crick’s identification of DNA’s structure, several other researchers had also studied it.
The “nuclein” identified by Miescher later came to be known as DNA—an abbreviation for deoxyribonucleic acid. German biochemist Albrecht Kossel is credited with naming it and went on to win the Nobel Prize for his contributions. In 1953, Watson and Crick unveiled the double-helix structure of DNA, a breakthrough that earned them the Nobel Prize in 1962.
However, despite their accolades, controversy arose years later when it was revealed that Watson and Crick had used critical data from chemist Rosalind Franklin’s research without her permission. It was her work—specifically her X-ray diffraction images—that provided key insights into the double-helix structure.
World’s Rotation
The idea that the Earth rotates on its axis and revolves around the Sun is widely accepted today. However, at the time of its initial proposal, this theory faced significant skepticism. Critics questioned how such rotation could occur without humans feeling it—”If the Earth were rotating, wouldn’t we notice?”
It was only through the relentless efforts of visionary scientists that this concept gradually gained acceptance. The notion that the Earth orbits the Sun can be traced back to ancient Greek astronomer Aristarchus. However, his ideas were not widely embraced in his time. The prevailing belief was that the Earth was the center of the universe, with the stars, planets, and Sun revolving around it.
Polish mathematician and astronomer Nicolaus Copernicus is credited with introducing the first heliocentric model of the universe. In 1543, he published his seminal work, On the Revolutions of the Heavenly Spheres, in which he explained his theories. One key concept was that the Earth rotates on its axis, resulting in the alternation of day and night.
Copernicus’ heliocentric model challenged the long-standing Ptolemaic system, which held that the Earth was stationary. Although Copernicus’ work received limited recognition during his lifetime, it eventually gained traction.
Galileo Galilei supported Copernicus’ theories and provided observational evidence using a telescope. In 1610, Galileo studied the phases of Venus and the moons of Jupiter, offering powerful proof against the geocentric model. He demonstrated that Venus underwent phases due to its orbit around the Sun.
German mathematician Johannes Kepler further refined the heliocentric model by detailing the elliptical orbits of the planets around the Sun. His mathematical laws of planetary motion, aligned with Copernican theory, remain relevant and accurate to this day.
Electricity
A widespread misconception persists that Benjamin Franklin discovered electricity through his famous kite experiment. In fact, Franklin’s 1752 experiment using a kite and a metal key did not discover electricity; rather, it demonstrated that lightning is a form of electrical discharge.
Another common myth is that Franklin was struck by lightning. In reality, while conducting the experiment during a storm, the kite become electrically charged, but Franklin was not harmed by a direct lightning strike.
The study of electricity dates back much further. Ancient Greek philosopher Thales of Miletus is credited with observing static electricity as early as 600 BCE by rubbing fur on tree resin.
British scientist and physician William Gilbert was the first to popularize the term “electric” and is often referred to as the “father of electricity.” Gilbert introduced terms such as “magnetic pole,” “electric force,” and “electric attraction.” In 1600, he published De Magnete, a six-volume work that laid the foundation for future studies in electromagnetism.
Germ Theory of Disease
The germ theory of disease is a foundational principle in modern medicine. According to this theory, many illnesses are caused by microorganisms such as bacteria and viruses. It significantly challenged earlier beliefs about the origins of disease.
French scientist Louis Pasteur was the principal figure behind the development of germ theory. He demonstrated that microorganisms cause decomposition, leading to the souring of milk and wine. Through experiments, he proved that these microbes could be destroyed by applying heat—a process now known as pasteurization.
This theory was a game-changer. By eliminating bacteria in food through pasteurization, the spread of illness could be effectively controlled. Prior to Pasteur’s work, it was commonly believed that diseases originated from within the body itself.
Pasteur’s groundbreaking research confirmed that germs from external sources invade the body and cause illness. His work transformed public understanding of disease and led to wider acceptance of germ theory, changing the course of both science and public health policy.
The Power of Gravity
It was a simple image—the sight of an apple falling from a tree—that sparked a profound thought in the mind of mathematician and physicist Isaac Newton. From that fleeting moment of curiosity, Newton, at the age of just 23, formulated the foundational concept of gravity. He pondered how a force or energy could pull objects directly toward the earth. The answer lay in gravity, a natural force that causes objects to attract one another. The greater an object’s mass, the stronger its gravitational pull. Conversely, the farther two objects are from each other, the weaker the force between them becomes.
Newton’s insights and his theory of gravitation were applied to explain phenomena ranging from the trajectory of a baseball to the Earth’s orbit around the Sun. Yet, Newton’s contributions did not stop there. In 1687, he published Philosophiæ Naturalis Principia Mathematica, commonly known as Principia. This seminal work elaborated on the law of universal gravitation and the three laws of motion. His contributions laid the groundwork for modern physics and remain a cornerstone of scientific understanding.
Antibiotics
Just as the germ theory of disease revolutionized modern medicine, it also paved the way for one of its most vital advancements—the discovery of antibiotics. These life-saving agents have played a crucial role in saving countless lives. According to the Microbiology Society, humans have been using various forms of antibiotics for millennia. However, the modern era of antibiotics began only after scientists identified the specific bacteria responsible for particular infections. This discovery allowed doctors to use targeted antibiotics to treat infections more effectively.
In 1909, German physician Paul Ehrlich observed that certain chemical dyes did not stain all bacterial cells equally. This led him to hypothesize that it was possible to selectively kill harmful bacteria without damaging surrounding cells. Ehrlich went on to develop a treatment for syphilis, which many in the scientific community recognize as the first true antibiotic. However, Ehrlich himself referred to his invention as “chemotherapy” because it involved the use of chemicals to treat disease. Owing to his pioneering work, Ehrlich is often called the “Father of Immunology.”
According to the Microbiology Society, the term “antibiotic” did not come into common usage until nearly 30 years later, when Ukrainian-born American microbiologist Selman Waksman introduced it to describe naturally occurring antimicrobial substances.
Among the most widely recognized antibiotics today is penicillin. Physicians prescribe it to millions of patients each year. Yet its discovery was serendipitous. In 1928, Scottish microbiologist Alexander Fleming returned to his laboratory after a short break and noticed that a mold called Penicillium notatum had inhibited the growth of staphylococcal bacteria on a culture plate. Fleming observed that the mold had created a bacteria-free zone around itself. Through a series of experiments, he successfully demonstrated that P. notatum had the ability to halt the growth of staphylococci. The mass production of penicillin soon followed, and during World War II, it became instrumental in saving numerous lives.
The Big Bang Theory
Among the many theories explaining the origin of the universe, the most widely accepted is the Big Bang theory. According to this theory, approximately 13.7 billion years ago, all matter in the universe was concentrated in an incredibly small point. A massive explosion from that point gave birth to the cosmos as we know it.
The concept of the Big Bang was first introduced by Belgian cosmologist and Catholic priest Georges Lemaître. In 1927, Lemaître published a paper addressing solutions to equations derived from Albert Einstein’s theory of general relativity. At the time, the paper received little attention. Many scientists remained skeptical of the idea that the universe was expanding. Nonetheless, a group of pioneering astronomers continued to challenge this skepticism through their work.
One such astronomer was Edwin Hubble. He observed that galaxies farther from us were receding at greater speeds than those nearby. This observation lent significant support to the idea of an expanding universe. Lemaître’s 1927 paper was later recognized for its significance, and in his 1931 publication, he formally introduced the term “Big Bang.”
Vaccines
Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure.” Though his advice was intended to caution against the devastating effects of urban fires, the sentiment is equally applicable to public health. The invention of vaccines has helped protect people from numerous serious diseases. Thanks to vaccines, the incidence of diseases like polio has dramatically declined, and smallpox has been eradicated.
According to the Centers for Disease Control and Prevention (CDC), a vaccine is a preventative method involving the introduction of a small amount of a disease-causing agent into the human body. This helps the immune system build resistance so that if the disease attempts to attack the body again, it can be fought off effectively.
The World Health Organization (WHO) notes that the first vaccine was developed in 1796 by Dr. Edward Jenner. Using material from cowpox sores—a disease similar to smallpox—Jenner created a vaccine. He tested it on an eight-year-old boy named James Phipps. Initially, the boy experienced discomfort, but he eventually recovered. Months later, Jenner exposed Phipps to smallpox, and the boy did not contract the disease. Jenner’s method saved countless lives, and his work marked the beginning of a new era in immunology.
The Theory of Evolution
The theory of evolution posits that genetic changes occur from one generation of organisms to the next, allowing them to adapt to their environment. Over time, changes in climate, food sources, or predators may influence physical traits such as color or beak shape, enhancing survival.
This theory was largely developed by naturalist Charles Darwin, who conducted extensive research on the animals of the Galápagos Islands—especially finches. He observed that while finches on different islands were of the same species, their physical traits varied significantly. For example, some had large, strong beaks suited for cracking nuts and seeds, while others had thin, pointed beaks better suited for catching insects. These adaptations reflected the ecological demands of each island.
Through these observations, Darwin earned the title “Father of Evolution.” His landmark work, On the Origin of Species, published in 1859, transformed the scientific landscape. While the theory has evolved since then, Darwin’s foundational ideas continue to shape the work of modern scientists.
CRISPR Technology
According to the National Human Genome Research Institute, CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats.” It is a revolutionary technology used by scientists to edit the DNA of living organisms. The development of CRISPR was the result of decades of research involving several key contributors, including Yoshizumi Ishino, Francisco Mojica, Jennifer Doudna, and Emmanuelle Charpentier.
In recognition of their pioneering work, Doudna and Charpentier were awarded the Nobel Prize in Chemistry in 2020. Researchers refer to CRISPR as a form of “molecular scissors” because it enables the precise cutting and editing of DNA. A 2018 study showed that scientists could use CRISPR to replace genes responsible for diseases such as cancer or hereditary disorders.
This powerful technology represents a new frontier in medicine and biotechnology, offering hope for treating previously incurable genetic conditions.
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