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---------------------------- 2285 - Science - on the shoulders of pioneers?
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- Andrea Cesalpino was born in 1519. He was a physician, philosopher and botanist at the University of Pisa until the pope, in need of a good doctor, called him to Rome. As a medical researcher Cesalpino studied the blood and had some sense about its circulation.
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- Cesalpino was most impressive as a botanist, generally credited with writing the first botany textbook. He described many plants accurately and classified them more systematically than previous researchers, who mostly regarded plants as a source for medicines.
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- Less than a month before Cesalpino was born, Leonardo da Vinci died on May 2, 1519. Leonardo is much more famous in the popular mind as an artist than a scientist, but he was also a serious anatomist, geologist, engineer and mathematician.
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- Leonardo’s role in the history of science was limited because so many of his ingenious ideas resided in notebooks that nobody read until long after his death. But he was a prolific and imaginative observer of the world. He developed elaborate geological views on river valleys and mountains. He thought the peaks of the Alps had once been islands in a higher ocean.
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- As an engineer, Leonardo recognized that complex machines combined a few simple mechanical principles, and he insisted on the impossibility of perpetual motion. He formulated basic ideas about work, power and force that became cornerstones of modern physics when developed more precisely by Galileo and others more than a century later. Leonardo would have invented the airplane if he had sufficient funding.
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- Petrus Peregrinus wrote a treatise on magnetism in 1269. Magnetism had been known since ancient times as a property exhibited by certain iron-containing rocks known as lodestones. But nobody understood very much about it until Petrus Peregrinus came along in the 13th century.
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- He left behind very few clues about his personal life; nobody knows when he was born or died. But he must have been a talented mathematician and technician
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- Petrus explained the concept of magnetic poles. He even realized that if you broke a magnet into pieces, each piece became a new magnet with its own two poles — north and south. But Petrus did not realize that compasses worked because the Earth itself is a giant magnet. Nor did he anticipate the laws of thermodynamics, designing what he thought was a magnetism-powered perpetual motion machine. You can’t fault a guy for trying.
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- On September 20, 1519, Ferdinand Magellan set sail from southern Spain with five ships on a transoceanic trek that would require three years to circumnavigate the globe. But Magellan made it only halfway, killed in a skirmish in the Philippines.
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- Juan Sebastián Elcano was commander of the Victoria, and the only ship of the original five to make it back to Spain.
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- Alexander von Humboldt was born in Berlin on September 14, 1769. Von Humboldt was not only a geographer, geologist, botanist and engineer, he was also a world-class explorer and one the most important writers of popular science of his century.
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- With the botanist Aimé Bonpland, von Humboldt spent five years scouring South America and Mexico for new plants while also recording 23 volumes’ worth of observations on geology and minerals, meteorology and climate, and other geophysical data.
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- Von Humbolt was both a deep and broad thinker, composing a five-volume work called Cosmos that essentially conveyed the totality of modern science to the general public.
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- Thomas Young was an Englishman famous for an experiment showing the wave nature of light, Young was also a physician and linguist. In 1819 he wrote a paper on the math related to the probability of errors in scientific measurements. He commented on the use of probability theory to express the reliability of experimental results in a numerical form.
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- Young warned that a trust in math without concern for other measurement considerations could lead to erroneous conclusions. Same is true if you trust politicians who use the math to further their agendas.
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- Johannes Kepler is one of the greatest physicist-astronomers of the 17th century, attempted to reconcile the ancient idea of the harmony of the spheres with the modern astronomy that he had helped to establish. The original idea, attributed to the Greek philosopher-mathematician Pythagoras, was that spheres carrying the heavenly bodies around the Earth generated a musical harmony.
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- Kepler believed the construction of the universe put the Sun rather than Earth at its center and he tried to observe these harmonious mathematical ratios. He had long sought to explain the architecture of the solar system as corresponding to nested geometrical solids, thereby prescribing the distances separating the elliptical planetary orbits.
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- In his “Harmony of the World” published in 1619, Kepler admitted that solids alone could not accurately account for the details of planetary orbits, additional principles were needed. Most of his book is no longer relevant to astronomy, but its lasting contribution was Kepler’s third law of planetary motion, which showed the mathematical relationship between a planet’s distance from the Sun and the time the planet takes to complete one orbit.
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- Albert Einstein’s general theory of relativity, completed in 1915, predicted that light from a distant star passing near the Sun would be bent by the Sun’s gravity, altering the apparent position of the star in the sky.
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- Newtonian physics could explain some such bending, but only half as much as Einstein had calculated. Observing such light seemed like a good way to test Einstein’s theory, except for the slight problem that you can’t see stars at all when the Sun is in the sky. This problem would be solved with the next solar eclipse making the stars near the edge of the Sun briefly visible and the measurements could be made.
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- British astrophysicist Arthur Eddington led an expedition to observe the eclipse from an island off the coast of West Africa in May 1919. Eddington found that deviations for some stars from their previously recorded location matched general relativity’s forecast close enough to declare Einstein the winner.
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- Demitrii Mendeleev was not the first chemist to notice that several groups of elements had similar properties. But in 1869 he identified a guiding principle for classifying the elements. If you list them in order of increasing atomic weight, elements with similar properties recur at regular periodic intervals in his table.
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- Using this insight he created the first periodic table of the elements, one of the grandest accomplishments in the history of chemistry. The periodic table is a wall chart. It allows anybody to grasp at a glance the foundations of an entire scientific discipline. It remains the most versatile consolidation of profound scientific information ever constructed.
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- Jumping a few centuries later, the Apollo 11 contributed to the science of lunar geology by bringing back moon rocks, the Apollo astronauts deployed experiments to measure moonquakes, studied the lunar soils and the solar wind, and left behind a mirror as a target for Earth-based lasers to measure the distance to the moon with high precision.
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- The Apollo mission represented a celebration of past scientific achievements. It contributed to our understanding of the laws of motion and gravity and chemistry and propulsion and mention electromagnetic communication
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- February 26, 2019
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