Historical Astronomers in Context

Nicolaus Copernicus  —  Born February 19, 1473 | Died May 24, 1543

Copernicus was important to astronomy because he proposed the heliocentric system that explained how planets orbit around the Sun. His central idea was that Earth, in addition to orbiting the sun every year, rotates once daily on its own axis. The slow changes in the direction of this axis account for the precession of the equinoxes.

Historical Events

During Copernicus’s lifetime (1473-1543), explorer Christopher Columbus completed his journey across the Atlantic Ocean and landed in the “New World” in 1492. Additionally, in the early 1500s, European countries established the slave trade in West Africa to obtain workers for the sugar and tobacco plantations in South America and the Caribbean. 

Historical Figures

Henry VIII (June 28, 1491 – January 28, 1547) and Leonardo da Vinci lived at the same time as Copernicus. Henry VIII was influential because he was the king of England from 1509 to 1547, and as king, he broke with the Roman Catholic Church and had Parliament declare him supreme head of the Church of England, which started the English Reformation. Leonardo da Vinci was best known for being an artist, who notably painted the Mona Lisa, and an engineer who is arguably credited as the inventor of the tank, helicopter, parachute, and flying machine. 

Reflection

I chose Copernicus at random from the selection of the five astronomers, but I’m really glad I got to research him! I’ve always heard his name thrown around in science classes, but I had no idea how influential he was to the development of our understanding of the solar system. His work directly ties into our whole past unit, so it was nice to have a name to attach the knowledge to. Additionally, I’m glad I was able to get a grasp on the time frame that these scientists lived in. It makes a lot of sense that Copernicus came before many of the other astronomers because their work was probably largely dependent on Copernicus’s. It’s also interesting that Copernicus came before Columbus’s exploration of the “New World”. If the understanding of our solar system was only developed decades before Columbus’s journey, then it’s clear why Columbus and his crew were shocked at their realization of how Earth’s geography works. 

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The Universe Isn’t Kepler-centric!

Johannes Kepler made three of the most influential discoveries to the field of astronomy, also known as Kepler’s Laws. Kepler was born on December 27, 1571 (a true Capricorn!), and died on November 15, 1630. In case you forgot:

Kepler’s 1st Law: planet orbits are elliptical (not necessarily perfect circles!) and the Sun is at one focus!

Kepler’s 2nd Law: The time it takes for a planet to travel part of the orbit is proportional to the area it sweeps out.

Kepler’s 3rd Law: There is a relationship between the period and average distance from the Sun.

Kepler’s Laws visualized! (APlusPhysics)

Kepler’s discoveries were used by Newton, who discovered the effects of gravity. Newton applied his discoveries and created a more general definition of Kepler’s 3rd Law (Newton’s Version!).

But while Kepler was alive, there was also a lot going on in the history and art scenes. In 1618, the Catholics and Protestants started beefing, which led to a war that involved many European nations and lasted for the next 30 years. That’s why they called it the “Thirty Years War” . In 1590, the Baroque art period started. The art from this time period was known for using dramatic and exaggerated colors and strokes. Also, William Shakespeare lived from 1564-1616, so he wrote many plays during the time that Kepler was alive! As you know, these plays are still performed (and analyzed in English class) to this day.

All of this shows that at any given time, there is so much going on in the world! While Kepler was busy figuring out how planets move, there were wars going on, art being created, and plays being written. And all of these events shaped future discoveries and developed art styles and cultures.

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Historical Astronomers in Context

Johannes Kepler (1571- 1630)

Johannes Kepler was an important contributor to astronomy after he created the three laws of planetary motion. The first law states that planets move in elliptical orbits around the sun, and the second law states that planets move faster in their orbits when closer to the sun. Lastly, the third law explains the relationship between orbit speed and distance from the sun. His discovery of elliptical orbits around the sun paved the way for many future astronomical discoveries.  

Historical Events

One major historical event that happened in the late 16th century, more specifically between 1592-98, was the Japanese invasion of Korea. Initially, the Japanese forces conquered the majority of the Korean peninsula but were driven back by Chinese reinforcements. This resulted in a stalemate, deeming the Japanese invasion a failure. Another historical event that happened around this time was the start of the Scientific Revolution. The Scientific Revolution changed the way Europeans thought by introducing the Scientific Method, a method of learning that involves heavy observation. The Scientific Revolution replaced philosophy with science and facts by starting a period of experimentation and questioning. 

Historical Figure

Another historical figure that was alive during the time of Kepler was William Shakespeare. Shakespeare was a worldwide renowned poet, famous for his works like Hamlet and Romeo and Juliet

Reflection

Learning about this time period and the historical figures/events during this time, opened my eyes to how long ago these observations were made. Astronomers like Kelper set the foundation for what we know today, and their experimentation has opened up tremendous avenues for astronomers who have come after them. It is incredibly interesting to see how these astronomers made such monumental discoveries with such little technology and help.

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blog 2: Gravity over time

Isaac Newton originally conceptualized gravity as a mutually attractive force between all objects with mass. Those who came before him, such as Galileo, had performed experiments and attempted to establish increasingly robust understandings of this force, but none quite unified the idea like Newton. The story goes that Newton saw an apple fall from a tree, which made him realize that this force (gravity) knows no bounds. It operates on Earth and in space. Newton brought forth many revolutionary ideas in Philosophiæ Naturalis Principia Mathematica (usually referred to as just Principia). Among them, Newton established laid out his three laws of notion (the consequences of which are briefly described here) and his universal law of gravitation. He formulated his theories describing gravitation inductively, meaning he reasoned backward from observations which he then used to construct a theory which he repeatedly tested. Newton did not actually establish the mechanism by which gravity worked in the way he said it did. In fact, in “General Scholium,” an addendum essay to Principia, he famously claimed to “formulate no hypothesis” explaining the mechanism by which gravity operated. He simply said that the force worked in a certain way, and for many years people accepted his formulation. They found no superior alternative.

A figure depicting Newton’s law of universal gravitation. By Dennis Nilsson on Wikimedia Commons.

Only once Einstein formulated the idea that spacetime was curved by objects with masses was a coherent explanation found for the mechanisms of gravity. Einstein ended an era of Newtonian physics by suggesting these massive objects curved the very “fabric” of spacetime, causing objects (which would otherwise follow velocity vector direction in a straight line) to move in towards the objects bending the fabric. One way to think of this is to imagine a trampoline with someone sitting in the middle of it. If you were to pour water onto the trampoline, the water would sink towards the person sitting in the middle of it. If there was no person on the trampoline (and we disregarded air resistance, friction and other such forces), the water would continue in a straight line on the trampoline until it came off the other side. Crucial to Einstein’s discovery were earlier formulations which combined our universal coordinates into four dimensions (the traditional length, width and height, with the added dimension of time). Our “position” in the universe would be defined by the combination of all of these factors, time included. The very fabric of the universe was thought to be spacetime, which was curved by the mass of objects. Finally, Einstein had answered the “why” of the gravity question. Within physics today, much of Einstein’s work remains standard, however there are some challenges that have emerged in recent times. Physicists in quantum mechanics have attempted to reconcile relativistic gravity with quantum concepts (in a search for “quantum gravity”) but have been unsuccessful thus far. Other problems, like some of specific the conditions of black holes (in which spacetime is infinitely curved) and the properties of dark matter and energy still pose some questions for Einstein’s formulations. We really have no way to know what the future may hold regarding our understanding of gravity’s mysteries.

A figure contrasting Newtonian physics and Einstein’s theories. By Gadarensis on Wikimedia Commons.

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Blog 1 – The Cosmic Calendar

Cosmic Calendar Image

The Cosmic Calendar summarizes the history of the universe into a way that is easy for humans to comprehend-one 12-month calendar year. The universe is about 14 billions years old, so each month of the year represents a little more than a billion years of the universe’s history. Using this model, all of human history can be condensed into the last few hours of the last day of the year. The dinosaurs would have gone extinct on December 30th. Early hominids would have evolved at 9:00pm on December 31st.

This way to visualize the history of the universe is incredibly helpful in visualizing and comprehending the vastness of the time that the universe has been around. Human beings cannot comprehend a large a number as 14 billion.

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Newton in Context

The five most important astronomical pioneers which we are studying in this course are Nicholas Copernicus (February 19, 1473 to May 24, 1543), Galileo Galilei (February 15, 1564 to January 8, 1642), Johannes Kepler (December 27, 1571 to November 15, 1630), Isaac Newton (December 25, 1642 to March 20, 1727) and Tycho Brahe (December 14, 1546 to October 24, 1601). Galileo and Kepler were contemporaries from 1571 to 1630, while Galileo and Tycho Brahe were contemporaries from 1546 to 1601. Kepler and Tycho Brahe were contemporaries from 1571 to 1601. All of these men made tremendous contributions to astronomy and the sciences as a whole. In this post I will focus on Newton and his chronological context specifically, but all of them lead interesting lives and left glorious achievements behind them.

A portrait of Isaac Newton. In the public domain.

Newton specifically was of paramount importance to not only astronomy, but all the sciences. His two most crucial developments were: calculus and the foundations of modern physics. Calculus is used rather extensively in all “hard” sciences, and especially astronomy, in which verifications and formulations of overarching theories require extensive calculus-based proofs. Secondly, Newton’s “foundational” work in physics is often expressed in his three laws (which, of course, do not exhaustively summarize Newton’s contributions to the field). In his famous three laws, Newton essentially expressed that net forces (the sums of all forces acting upon objects) and are necessary to make changes in an object’s momentum, that force strength equals the mass times of an object times the acceleration applied and finally that all forces have opposing “reaction” forces with equal magnitude but opposite direction. Other Newtonian conceptions have proven extremely durable. Many of Newton’s discoveries uprooted thousands of years of cosmological thought, and some have proven exceptionally durable.

One notable event in Newton’s lifetime (and country) was the Great Fire of London, which occurred in 1666, when a young Newton was only 23 years old. Although the Great Fire of London was not astronomical in nature, it caused damage of an absolutely astronomical nature. The fire burned significant parts of Central London, destroying national architecture and infrastructure, including the famous St. Paul’s Cathedral.

Another notable event during Newton’s lifetime was the Great Northern War between a coalition headed by the Russian Tsardom against the Swedish Empire. Russia and its coalition allies successfully toppled the previously unrivaled Kingdom of Sweden in Northern Europe. The war lasted from 1700 until 1721, which was only two years prior to Newton’s death.

One of Newton’s famous contemporaries was Charles XII of Sweden, who was a belligerent (and King of Sweden) for much of the Great Northern War. Being only 36 at the time of his death in 1718, he won several “upset” victories (he proved himself a highly capable military commander) against his coalition opposition. He eventually succumbed during the Siege of Fredriksten.

I happened to know much of the general context of Newton’s lifetime and events due to reading I’ve done over the years, but what surprised me was just how prevalent astronomy was during Newton’s lifetime. When I was looking for contemporary figures (of Newton) to mention, I hit a wall twice in a row with Christopher Wren, Robert Hooke (they both did rather substantial astronomical work which I didn’t know about). In these times, it seems that many people were polymaths!

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Nicolaus Copernicus under Historical Context

BBC Sky at Night Magazine

Nicolaus Copernicus’ (Feb. 19, 1473 – May 24, 1543) contributions to the field of astronomy are best summarized as the “Copernican Revolution”, where he rejected the long-held theory of a geocentric model of the solar system, meaning that Earth was stationary at the center while celestial objects orbited around it. Instead, he put forth the heliocentric model, where the Sun is at the center of the solar system and causes all other nearby celestial bodies to orbit around it, including Earth. He devised three laws to explain the behavior of planetary motion around the Sun: one, that these orbits were elliptical (oval) and not circles; two, while a planet’s speed will change as its distance from the Sun increases or decreases, it will always encompass equal amounts of space over the same time frame between it and the Sun; three, the period of a planet’s revolution about the Sun is directly proportional to its distance from the sun.

During Copernicus’ lifetime, the Italian artist Leonardo da Vinci completed his work on the most famous painting of all time: the Mona Lisa in 1506. The painting is generally crowned as the singular masterpiece of the Italian Renaissance. Copernicus also witnessed the Church of England splitting from the Catholic Church over a political power struggle between King Henry VIII and Pope Clement VII in 1532. Lutherism, which was born out of Martin Luther’s 95 theses and the impact of the Protestant Reformation – another ideological split within the church about a decade before – took on a major role and influence within the new Church of England as they supported King Henry’s attempt to break away from the Catholic Church.

Martin Luther (Nov. 10, 1483 – Feb. 18, 1546) was a German, Catholic priest responsible for the Protestant Reformation. He published his 95 Theses to challenge the Catholic Church on the practice of religious indulgences, where worshippers were able to pay to “lessen” the weight of their sins for when they reached the afterlife, and the ensuing fallout of the Church’s attempt to smear his claims and kill him lead to a major split in Christianity that gave birth to the Protestant branch of the religion.

Researching the lifespans of the five astronomers in question raised the observation that, barring Galilei and Kepler, these great scientists rarely overlapped with each other. It can be taken further if including more recent astronomical figures such as Charles Messier, who cataloged deep-sky objects like galaxies and nebulas in the mid 1700-1800s, and Albert Einstein in the 1900s. The concentration of brilliant astronomers who left a meaningful discovery on the field has increased in the past century or two, likely caused by education becoming much more widespread around the world. It was rather obvious that many of the historical astronomers were white, well-connected men, often of noble backgrounds, as they were the few who could have the education, resources, and opportunity to pursue their studies.

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Historical Astronomers in Context -Cameron Klein

Britanicca

The astronomer that I have selected to look into is Tycho Brahe. Tycho Brahe was born on December 14th, 1546 and died on October 24th, 1601. Tycho Brahe was known as the best naked-eye observer of all time. During his childhood in Denmark, Brahe became entranced with the thought of astronomy when he witnessed a solar eclipse take place exactly at its projected time. In order to be able to predict eclipses for himself, he built an observatory on a private island given to him by the King of Denmark. He built a semicircle that he mounted to the wall in order to be able to determine the positions of planets and stars in the sky in relation to each other as accurately as possible. He lived on this observatory island until he got in a fight with the King of Denmark, who then forced him to leave. Perhaps Brahe’s most significant discovery was when he witnessed a supernova and realized that the universe was changing with time. Brahe’s discoveries have left a lasting impact on the astronomy world since his death and will cotinue to make an impact for years to come.

There were several significant historical events that occured during Tycho Brahe’s lifetime. In 1555, a group of Africans from Ghana (what was then known as Shama) were transported to London for the slave trade by London merchant John Lok. This was the first time that slaves had been brought to England. In 1593, Queen Elizabeth I’s doctor, Roderigo Lopez, was found guilty of attempting to poison her. To pay for his crimes, he was hung publically, and his death resulted in a large spur of anti-semitism in the country. Additionally, Brahe lived during the same time as Ivan the Terrible. Ivan the Terrible lived from 1530-1584 and was a monstrous Tzar of Russia for many years. He relentlessly conquered countries around him and even killed his own son in an argument.

Learning more about these famous astronomers was extremely rewarding for me. As we continue to delve into the class content, having the background information of the people whose discoveries that the foundation of our class relies on was beneficial for me to learn about. I believe that the most beneficial portion of this assignment for me was to learn about the historical events that happened during the time of Tycho Brahe’s existence. This helped to give me context about what else was occuring during the time of these major astronmers lives. This assignment helped me to realize that the timeline of astronomers’ discoveries was much longer ago than I had previously thought. I expected the discoveries to have taken place much later than the 1500s.

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Johannes Kepler in Context

Wikipedia

Johannes Kepler was born on December 27th, 1571 and died on November 15th, 1630. He is considered to be a pioneer in astronomy because of his three laws of planetary motion. His first law states that orbits are ellipses, so their motion follows conic sections. His second law states that in an orbit, equal areas are swept out in equal times, so that a planet’s orbital speed is faster the closer in distance it is to the Sun. His third law describes the mathematical relationship between distance of the Sun and time to orbit as P2 = ka3. His discoveries changed the way astronomers think about planetary orbits and are still influential today.

Kepler lived in the same time period as many major historical events. In 1611 the King James Version of the Bible was published for the Church of England. In 1620 the Pilgrims arrived in Plymouth, Massachusetts after traveling from England on the Mayflower. In addition, Kepler lived at the same time as William Shakespeare. William Shakespeare was born on April 26, 1564 and died on April 23, 1616. Shakespeare is considered one of the most famous playwrights to ever live and his works are still studied and performed today. Some of his most famous works include Hamlet, Romeo and Juliet, and King Lear.

It was really interesting to learn about the timelines of when these people lived because it helped me put their lives into context. Before doing this it was really hard to place these astronomers and their discoveries on a timeline that was relevant to me, but connecting their lives to other historical figures and events helped with that. It was interesting to learn about what else was going on in the world when these astronomers were alive.

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Blog 1

How did we come up with the names and positions of the constellations in the night sky? This is a question I will be answering in this blog, and I hope to contribute to the diverse themes presented in the book. My focus is on the Arabic contribution to the naming of the stars and constellations. The history of Islamic astronomy is marked by the development of astronomy across three continents. As Arabic was the common language of that era, most knowledge was acquired in Arabic. Scholars from Central Asia, the Middle East, to North Africa, and most notably Al-Andalus (modern-day Iberian Peninsula), observed the sky as a means of understanding God’s creation and strengthening their faith in their respective religions. Among these scholars was the Persian polymath Abd al-Rahman al-Sufi. I will point out two constellations from his book “The Book of Fixed Stars,” written around 964 AD. The first example is al-Jady, commonly known as the Algedi constellation, which translates from Arabic as “the Goat.” Its scientific name is Alpha2 Capricorni, a southern triple star system in Capricorn. The second example is the constellation commonly known as Albali. Its Arabic name is al-Bāliʽ, translating to “the Swallower.” Scientifically, it is identified as the single star Epsilon Aquarii in Aquarius.

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