A Brief History of Astronomy

This section includes a wide selection of famous astronomers and their stories; what they contributed to astronomy, how they led their lives, and whether or not they owned moose (yes, an astronomer did own a moose!) So feel free to delve in and read anything you would like; there's something here for everyone!

Section One: Ancient Astronomy (500 BCE – 500 CE)

Ancient Astronomy is a diverse topic with a multitude of people calling out to be recognized for their contributions. One of the most creditable achievements of astronomy as a field is that it gained momentum before the common era, and never lost it, from these ancient civilizations, to the influence of Islam in the Dark Ages, to the Renaissance soon following it. These ancient astronomers all set such a strong foundation for the science that it is the only reason that we are as far as we are. If these achievements and discoveries never occurred, modern astronomy would be like attempting to solve a complex differential equation without knowledge of basic arithmetic: it’s bound to end in disaster.

In this period, there is much to discover and much to learn. The building of this foundation took a long time and involved several people, each with their own creditable qualities and impressive achievements. While it is impossible to cover every single astronomer from this time period, I wish to cover as much as I can, as succinctly as I can. So, without further ado, feel free to dive in!


Meet the high school winners of U of T's Aristotle Contest ...Credit: University of Toronto

Aristotle’s greatest achievement—one that some people in today’s day and age would do well with following—was the proposition that the Earth is not flat, as people had envisaged, but round. His evidence for this was multifaceted to say the least. Firstly, the shadow that the Earth cast on the moon was round, pointing to it being a spherical body. Secondly, Aristotle shrewdly analyzed rudimentary star-charts made on voyages and noticed that the North Star (Polaris) was positioned lower in the sky in lower latitudes. And lastly, if the Earth was flat, he said, why do you see the sails of a ship before you see the hull as it comes above the horizon? Armed with these three pieces of evidence, he published On the Heavens in 340 BC. Not bad for someone whose primary claim to fame is a biological classification system.



Credit: Wikimedia

Aristarchus isn’t known very well because his theory, while right, was rejected in favor of Aristotle’s and Ptolemy’s (we’ll get to him later). This theory, of course, is heliocentrism. Although credit for the theory of heliocentrism generally goes to Copernicus, Aristarchus was the first to propose the idea. In fact, according to some sources, Copernicus attributed the idea to Aristarchus. The idea consists of the radically simple fact that the sun is the center of the known universe, however, it was as unpopular in Aristarchus’s time as it was in Copernicus’s. Geocentricism was the theory that reigned in both cases (the Earth is the center of the known universe). As a result, poor Aristarchus slid into the dark corners of history that are often never found. His contribution to modern astronomy, however, should never be forgotten


 The History Reader - A History Blog from St. Martins PressCredit: History Reader

Eratosthenes has a fascinating claim to fame; he estimated the circumference of the globe. Yes. Without any satellites, without calculators, without computers, without large amounts of data, without—well, anything that we use today—Eratosthenes was able to put the circumference of the Earth at about 41,600 kilometers (0.4% off from the real number) using two shadows. If that isn’t an impressive feat, I don’t know what is! His experiment was revolutionary in its simplicity, yet its usefulness; it formed an estimate that shaped calculations for years to come. This was his process.

Eratosthenes observed two cities—Alexandria and Syene—that lay on the same line of longitude. Syene was on the Tropic of Cancer and therefore had the sun directly overhead on the summer solstice. Alexandria, however, was not; as a result, the sun cast a shadow on the summer solstice. Eratosthenes then took two observations; first, the distance between the two was about 5000 stadia[1]; second, the angles made with the shadows was about 7°, or 1/50th of a circle. Taking these two pieces of information, he estimated the Earth’s circumference to be 5000 x 50 or 250,000 stadia.

What impresses me the most about Eratosthenes was that he is proof that technology should never be a permanent obstacle, only a temporary hurdle; when the human mind is applied to a problem, it will always find a way. It’s a lesson that all of us in a modern era should be hard-pressed to follow.


[1] One stadia is approximately 185 meters


Hipparchus Biography - Childhood, Life Achievements & Timeline 
Credit: Biography

Hipparchus was famous for creating the first star chart. While this may seem inconsequential, the star chart was essential to achieving a better understanding of the night sky. A complete map of the sky has several uses that range from easier navigation to better understanding of constellations; it made the sky something tangible and enabled astronomers worldwide to have the same context. Because the northern and southern hemispheres both experience different skies, it was often confusing for astronomers to understand what their colleagues were referring to; the introduction of the star chart enabled that consistency. And, of course, the plethora of “sky map” apps that can be found today are all based on a star chart. Who knew?


 Newsela | The Astronomers: Claudius PtolemyCredit: Rice University

Ptolemy, interestingly, is famous for being wrong. While respect is given to him for his thought process, he created the model of the universe that is considered completely inaccurate: the geocentric model. What is admirable, however, is the amount of detail he put into this model. He created the concept of epicycles (smaller orbits within orbits) to explain the motion of planets in relation to the sun; additionally, he was able to predict relatively accurately where planets would end up. Considering the complexity of the model, it was soon discarded at the onset of the Scientific Revolution, in favor of the simpler heliocentric model. However, Ptolemy will always be remembered as one of the first astronomers to make a detailed model of the solar system that seemed to match observations.

Section Two: The Middle Ages (500 CE – 1300 CE)

The Middle Ages are also known as the Dark Ages, a bit of a misnomer when non-Eurocentric history is considered; while Europe did, in fact, descend into squalor and darkness, it was the Golden Age of the Indian Subcontinent and the Islamic Empire.

During this Golden Age of India, several important scientific and mathematical milestones were achieved. The concept of 0 was established for the first time; complex astronomical observation stations, Jantar Mantars, were established throughout the country. The most incredible part about these stations, however, was that they were analog computers; they could be used to make calculations that were otherwise impossible.

In the Middle East, meanwhile, Islamic scholars had formed a base at Baghdad; its famed House of Wisdom attracted learned individuals from around the world. As the newly formed Islamic Empire was at the crossroads of the trade routes between Europe and Asia, it profited tremendously from these interactions and grew rich and prosperous. This was a conducive environment for the sciences and the arts; from epics in literature such as the Shahnameh to landmark works in mathematics such as the Al-Jabr (incidentally, the modern term “algebra” originated from here).

Several important tenets of modern science were established here, and the characters that established these tenets are no less colorful and fascinating than the Greeks of the Ancient Era. So, without further ado, let us dive into the rich stories of astronomical achievements in the Middle Ages.


Aryabhata Biography - Childhood, Life Achievements & TimelineCredit: The Famous People

Aryabhata is primarily famous for coming up with the concept of the number “0”. This is something that is fundamental in mathematics, something used by elementary schoolers doing simple arithmetic and college students cracking differential equations alike; one might think that this discovery would be enough for a lifetime. Aryabhata, however, thought differently.

One of the most impressive facts about Aryabhata is that he had a college education. He attended a university called Nalanda in the city of Patliputra. But that wasn’t the most impressive of his achievements: he went on to become the head of the university, establishing an observatory at a nearby Sun temple.

It was through this observatory that he made a landmark observation: the moon does not have light of its own—rather, it shines with the reflection of sunlight. This would form the foundation of understanding planets and studying planetary motions in the future; and, of course, is the reason that photographers can capture the moon without burning their lenses.


 Brahmagupta - Bing Image A famous Indian mathematician ...Credit: Famous Mathematicians

Brahmagupta was, according to science historian George Sarton, “one of the greatest scientists of his race and the greatest of his time.” While Brahmagupta has several important achievements in mathematics—in fact, he derived the formula of finding the area of cyclic quadrilaterals—he has several important achievements in astronomy as well. Brahmagupta was able to accurately calculate the parallax and apparent motion in the planets as well as the motion of the stars in the night sky; he also accurately described the phenomenon of eclipses and he was able to calculate the instantaneous mass of a planet. In other words, his repertoire of achievements is quite broad, and on par with any respectable Renaissance scientist.


Lalla is famous for being the forerunner of successful modeling of astronomical systems with mathematics; he was able to accurately map and predict the phases of the moon as well as calculate planetary and astral conjunctions. He was additionally famous for writing treatises on instruments used in astronomy; everything that he used to observe the heavens, along with their directions, were clearly outlined in his lucid work. He was able to draw on the works of his forerunners to discover more fantastical concepts; his work was the foundation for applied mathematics as well as astrophysics.


 Al-Khwarizmi - Astronomer and MathematicianCredit: ThoughtCo

An interesting figure, al-Khwarizmi is the first major astronomer in the Golden Age of the Islamic Empire. He is famous for the landmark work “Zij al-Sindh”, that contained detailed diagrams and tables that detailed the motions of the Earth as well as the moon and five other planets. This work was especially significant because it was the first Arabic work to utilize Ptolemaic concepts into Islamic sciences. It also marked the beginning of using non-traditional methods to study the sky; Khwarizmi was the first to introduce these methods in his book.

Ibn Al-Haytham

 Credit: Ahram 

Ibn Al-Haytham was at the head of a revolution aimed at criticizing Ptolemaic astronomical stipulations. This new wave disagreed with some of Ptolemy’s claims based on their own observations and was not shy in voicing it. They believed that the Earth’s axial wobble, also known as precession, was more severe than Ptolemy had predicted; about 1 degree of change in 74 years instead of 1 degree every 100 years.

Additionally, they disagreed with several aspects of Ptolemy’s geocentric model, and set about making their own changes to it; Al-Haytham dictated the issues in his book and several researchers took to his challenge to make more perfect models of the solar system. Eventually, it was the work of these Islamic astronomers that Copernicus used to make his not-so-landmark observation that the sun, not the Earth, was the center of the solar system.

Section Three: The Renaissance (1500 CE – 1850 CE)

The word “renaissance” literally translates to “rebirth”. This is a fitting epithet for this era in astronomical history. Specifically, of course, the rebirth refers to a re-introduction of the sciences and the arts in Europe; it is considered the start to the Early Modern period. This is the period of history when the foundation of astronomy is built upon and expanded to a larger degree; it is the period that includes recognizable names, from Galileo Galilei to Isaac Newton. It is the period in which astronomy developed to such a degree that it became a subject of global prominence; people around the world began to dedicate more and more time to astronomical pursuits.

This is also the period with the most eccentric characters and fascinating stories in astronomy. Almost every single astronomer featured in this section deserves a full-length biography; indeed, some of them do. I, however, will do my best to do justice to these fascinating scientists. From the various oddities of Brahe to the almost antisocial reclusiveness of Newton, there is a lot here that is to be found; stories and information are peppered throughout this period like nuggets of gold in a riverbed. But, enough setup; let’s delve into this influential period in the development of astronomy.


Heroes of Space: Tycho BraheCredit: Space Answers

I would like to start this section with Brahe, perhaps the most colorful of all the Renaissance-era astronomers. While yes, he is famous for a couple of things (incidentally, he gave the right evidence for being wrong) he was also famous for wandering around Europe with—and I kid you not—a dwarf jester (who he believed was clairvoyant) and a drunken moose.

Brahe’s primary achievement is the most detailed description of the stellar parallax to date. He believed in the geocentric model, often getting into heated debates with Galileo about it because he felt that if heliocentrism was true, stellar parallax had to be observed. But what, indeed, is stellar parallax? In short, it is the apparent motion of stars; if one observes a star during June and then again during December, it will have “moved” from its original position. Brahe, of course, simply did not have powerful enough instruments to recognize that parallax was, indeed, a thing; he reasoned correctly, however, that if the Earth orbited the Sun, stars will have moved at different times of the year.

Brahe’s end, however, is an interesting story. Once, at a banquet in Prague, he drank too much wine and desperately had to relieve himself. Unfortunately for Brahe, etiquette forbid him from departing the party early. He died 11 days later of bladder complications. An unfortunate thing for someone who predicted an essential aspect of modern astronomy hundreds of years before it was proven.


For Copernicus, A 'Perfect Heaven' Put Sun At The Center : NPR Credit: NPR

Copernicus might be one of the most important scientists in this section. While his story is considerably less fascinating than Brahe’s, he nevertheless had an important impact on the development of astronomy from this point on. Copernicus, of course, is known for re-introducing the heliocentric model into modern academia. There was a flaw in his design, however; his model had the planets moving in perfectly circular orbits and did not match observations. He was also afraid of offending the Church at the time and chose not to preach the theory as much as Galileo did. But we’ll get to that later.


 Kepler's Genius: Letting Nature Have The Last Word | NCPR NewsCredit: NPR

When talking about Copernicus, it isn’t possible to ignore Kepler. Johannes Kepler was, incidentally, an assistant to Brahe in Prague. How he managed to develop the most accurate heliocentric model of his time while working under someone who was vocally geocentric is beyond me, but modern astronomy owes a lot to him for his calculations. But what, you might ask, was so special about his model?

Kepler was the first to understand that the orbits of the planets were actually ellipses—in layman’s terms, squashed circles—and that their acceleration was variable; as they neared the sun, they sped up, and as they went farther from the sun, they slowed down. This simple change to Copernicus’s model not only fit observations at the time but also resulted in Kepler’s Three Laws of Planetary Motion about 100 years before Newton’s Three Laws of Motion. They are as follows:

  • All planets move around the sun in elliptical orbits, with the sun as one of the foci[1]
  • Planets sweep out equal areas in equal time periods
  • P2 = A3 (P is the orbital period of the planet; A is the orbital distance of the planet)

If none of that makes sense, don’t fret, because here’s an explanation. So, Kepler’s First Law is essentially saying that all planets have elliptical orbits. Not a new idea. It, however, specifically postulates that the elliptical orbits that the planets follow have the sun as one of the foci. Look at my footnote for more information about foci, but I promise you, it isn’t a challenging concept.

Kepler’s Second Law might be a little harder to decipher, but the concept is equally easy. What it means is that if you watch a planet for three months in any period of its orbit, it’ll have “swept out” the same amount of area—in other words, if you form an imaginary sector with the two positions of the planet (one at the start of the three months and one at the end) as two vertices and the sun as the third vertex, then the area of that sector will be equal in equal time periods.

Kepler’s Third Law is, perhaps, the most mathematical of the three. It states that the orbital period of a planet squared is directly proportional to the orbital distance cubed. Kepler was able to understand that the two would have a definite relationship in an elliptical orbit and was also able to quantify it. It makes logical sense if you think about it; the longer the distance that the planet must travel, the longer the time it will take to travel that distance.

So, there you have Kepler. Perhaps one of the most important figures in the Renaissance-era group of astronomers, modern astronomy owes a lot to this German astronomer and mathematician. In almost every astronomy classroom in the United States, Kepler’s Laws will be as ubiquitous as cheesy puns. And, in fact, these laws are still used to predict planetary locations and motions!

[1] A foci one of the two parts that ellipses are stretched out around. One way to think about it is that circles have just one focus (it’s center), and if you stretch the circle, you can envision another “center” beside it


Galileo Galilei and His InventionsCredit: ThoughtCo

Galileo is, perhaps, other than Newton, the most famous—or rather, prominent—figure from this era of astronomy. In the years that he was a practicing science, he had four landmark observations that directly affected the perception of astronomy at the time, affected the way that astronomy would develop over time, and disproved several tenets that the Roman Catholic Church had held at the time, leading to his ostracization—an unfortunate situation considering that he was a devout Catholic himself.

But what, you might ask, were these discoveries that enraged the Catholic Church to a degree that they would ostracize one of their own members? Galileo has four major discoveries, each of which disproved an aspect of the theological theory of astronomy that used to be preached by the Roman Catholic Church, and they are as follows:

  • Venus has phases like the moon
  • Jupiter has its own moons
  • The moon has craters
  • The sun has sunspots

The first and second discoveries, the phases of Venus and the moons of Jupiter respectively, both served to disprove the theory of geocentricism. For the first discovery, Galileo’s reasoning was as follows: if Venus had phases, it had to be consistently forming the same angles cyclically with the sun to have a shadow across it, meaning that Venus couldn’t be orbiting the Earth! The discovery of Jupiter’s moons[1] was much more direct evidence that geocentricism couldn’t be right; if there were moons orbiting Jupiter, they couldn’t be orbiting the Earth!

The third and fourth discoveries were more direct slights to the theological postulation that all heavenly bodies were perfect. If the moon had craters and the sun had sunspots[2], the heavenly bodies weren’t perfect, were they?

 Even more fascinating than the discoveries themselves was how he made the discoveries in the first place; he took the idea of a common glassmaker called Hans Lippershey about a sequence of lenses and chose to turn it to the stars. You and I, of course, know this as the telescope.[3] It enabled him to make these discoveries with more ease than would have been possible with naked-eye observation. These discoveries, additionally, had an unintended consequence that would haunt Galileo for the rest of his life.

Indeed, Galileo is most famous for the events surrounding the end of his life—about how he had a publicized spat with the Roman Catholic Church, was forced to recant his theory of heliocentricism. Yet, during his hearing, Galileo still had the nerve to whisper under his breath, “And yet [the Earth] moves.” He was then committed to house arrest, then went blind (presumably because of his unfortunate habit earlier in his life of staring at the sun through a telescope for hours) and then died of complications. Quite an unsavory end to such an illustrious scientist!


[1] The first four of Jupiter’s moons—Enceladus, Callisto, Io, and Ganymede—are called Galilean moons in honor of their discoverer

[2] Darker areas of the Sun where the magnetic fields interact

[3] This is one of the biggest misconceptions in history; Galileo did not invent the telescope. He chose to point it at the stars and improved it, but the former honor resides with Hans Lippershey.


Philosophers Squared – Isaac Newton | Probaway - Life HacksCredit: Probaway

Isaac Newton is perhaps the most famous astronomer from this era. He is known ubiquitously for the achievement of discovering the effect of gravity—and, perhaps less ubiquitously, for modeling it mathematically—and for the anecdote of the falling apple. I’m sure you’ve heard it before: how Newton was standing under an apple tree, and an apple fell on his head, causing him to somehow gain limitless insight into the inner workings of gravitation? Of course, there are some elements of exaggeration in this story, but it is highly possible that Newton’s observation of a falling apple resulted in his thoughts edging toward gravity—what caused it, and how to mathematically model it.

Newton’s greatest achievement, however, is not one that might be widely known. What excites the scientific community the most is Newton’s astoundingly comprehensive work, the Principia Mathematica, which spanned over four topics in science and mathematics to form the most detailed description of physics until that date. In the first chapter alone, Newton proceeded to—and I’m not exaggerating here—invent the mathematics that we now call calculus. Yes, he invented an entire field of math.

Armed with this newfound knowledge, Newton was able to solve problems that no one had been able to solve before—for example, how to find the slope of a curved line. Or how to find the area under a curve.[1] It was this foundation of mathematics that enabled future astronomers and astrophysicists like Einstein (we’ll get to him later) to model their equations to more accurately represent a proper curvature of space and time.

That is impressive enough to go down in the science Hall of Fame, but that’s not all that Newton was able to discover. Indeed, Newton has a few more significant achievements under his belt. Firstly, Newton was able to create a detailed model of gravity with his calculus discoveries, resulting in a general gravity equation that most high school students know as the universal law of gravitation:

This is perhaps one of Newton’s most incredible contributions to the scientific world. It states that the force of gravity between two objects is directly proportional to their masses and inversely proportional to their distance squared. This forms the essence of astronomy and astrophysics and it highly useful in calculations from calculating orbital trajectories to calculating the gravitational lensing of stars. Newton had other equations to dictate the motion of objects, which worked for everything except, surprisingly, the motion of Mercury. This, of course, is something that Einstein would remediate in the future with his equations of relativity.

Newton’s second additional achievement is something that every elementary schooler is familiar with; his three laws of motion. They are as follows:

  • An object in motion (or at rest) will stay in motion (or at rest) unless acted upon by an unequal and opposite force.
  • F = MA
  • Every action has an equal and opposite reaction.

All three of these laws are essential to astronomy and physics. They form the holy trinity of what everything that this described with physics must follow. They can be used from situations as simple as problems in your homework to complex math to describe a rocket’s journey into orbit. Yes, even rocket science uses something as basic as Newton’s Three Laws.

The First Law is also known as the law of inertia. It is relatively self-explanatory; an object that is moving will keep moving unless another force affects it; an object at rest will stay at rest unless another force affects it. This is a principle that can be used to describe satellites in orbit around the Earth; they are in motion at such a speed that even though they are still falling toward the Earth, their forward motion prevents them from falling through the atmosphere. In this case, both forces cancel each other out, enabling the ISS to have perpetual motion around the Earth. Too much force one way or another, however, and the most impressive engineering feat of the late 20th and early 21st centuries either crash into the ocean or goes hurtling off into space. That is the power of inertia.

The second law is also equally revolutionary as the first law. The simple equation F=MA has several uses as well. It is essentially stating that the force that an object exerts is equal to its mass multiplied by its acceleration. This makes logical sense when you think about it. A glacier moves very slowly but still exerts considerable force because of its mass; a bullet has very little mass but has a lot of force because of its acceleration. This kind of math comes in use when one is trying to get an object to exit the atmosphere of the Earth; in order to accelerate to a speed of 11km/s[2], what equilibrium must be reached between the mass of the rocket and its thrust? This is a simplified rendition of the actual calculation, but I hope you get the idea.

The third law is what enables rockets to take off in the first place; the way that rockets generate thrust is by combining fuel and burning it to expel hot gases that propel it upward. This would not happen if Newton’s Third Law was not accurate. Newton’s Third Law is also the reason why it hurts so much when you stub your toe, and also why us humans are able to float on water; the water is able to push back on you as much as you push on the water.

The last of Newton’s achievements is the detailed research that he conducted on light and its properties; specifically, the development of the visible light spectrum. Using preliminary methods of spectroscopy such as a pure glass prism, he was able to separate the light of the sun into its component colors (violet, indigo, blue, green, yellow, orange, and red). He dedicated a major part of his life to understanding color and what caused it as well as the interaction of light with other objects.

Newton was a highly accomplished scientist who was one of the biggest names in astronomy, physics, and mathematics. A reclusive lifestyle, however, contributed to the loneliness that would surround him until his death in 1727; he will, however, always be remembered as one of the founders of classical physics and one of the most instrumental figures in creating the foundation of what is familiar to us today.


[1] The slope of a curved line is known as it’s derivative and an integral is an area under a curve.

[2] The escape velocity of the Earth

Section Four: The Modern Era (1850 CE – Present Day)

This Modern Era is sprinkled with gems of astronomers who have contributed considerably to our current view of the universe—in fact, it would not be an overstatement to say that they have created our current view of the Universe. The astronomers and physicists in this era range from familiar names like Einstein and Hawking to lesser known names with equally impressive achievements such as Hubble and Schwarzschild.

The late 19th and the 20th centuries were hotbeds of scientific development and discovery, and much of modern science originated during these tumultuous times. The onset of two of the most destructive wars in the history of humankind did not deter science, though; many scientists worked hard to support their countries’ war efforts. And out of the ashes of violence and destruction followed by an equally barrier-creating Cold War came a period of relative stability and cooperation.

This was a time of exponential development. People went from struggling to create steel to creating new elements in a matter of 50 years; the fields of cosmology and astrophysics were catapulted into fame while the field of quantum mechanics was created; computing developed from entire rooms filled with enormous computers to mobile devices with more computing power than all those computers combined. And as the most turbulent 100 years of human history culminated in a new millennium, we have broken the limit of the sky and proceed to hurtle inconceivably quickly into that shining land of scientific discovery.


 Happy birthday, Albert Einstein | Human World | EarthSkyCredit: EarthSky

It seems fitting to start this section with the most celebrated scientist of the modern era, if not the most celebrated scientist in the history of our species. I will start out this section by saying that I will not be able to do justice to the immense scope of Einstein’s life and career. I will try to cover all the major events and achievements of his life, but for a deeper dive into his genius and his persona, I implore you to pick up any biography. But anyway, here goes!

Einstein was born to Jewish parents in 1879 in Ulm, in what would become Germany. While no one thought he was especially bright as a child, he showed a deep curiosity of science, from being fascinated by a compass to suggesting answers to problems that were posed by his uncle (an engineer). Einstein also grew up surrounded by books and was an avid reader; his family would often invite a poor university student over, and young Albert had extensive conversations with this pupil.

Although the myth that Einstein failed math as a student is indeed delicious, it is untrue. Einstein was top of his class when it came to mathematics. However, the story that he dropped out of school is true, albeit for different reasons; he merely did not like the militarization of education and moved to Italy with his family.

After completing his primary education, Einstein applied to university and made it into the Zurich Polytechnic. It was here that he met his future wife, a certain Mileva Maric; historians in the future would forever debate about how much his ideas were affected by her, how much of an impact she had on his thoughts, and how a married life would affect the pursuit of scientific knowledge. When things got sticky between them in the future, Einstein famously promised Mileva the prize money from the Nobel Prize as part of the divorce agreement. Four years later, Einstein won the prize and gave Maric the money.

After graduating from college, Einstein got a job as an examiner in the Zurich Patent Office. Essentially, he would review the applications of various patents that would come to him, and then approve or disapprove them. While this might seem to be a menial and demeaning job for someone who was about to revolutionize physics, it was actually a great opportunity for the young Einstein to fully flesh out his ideas while earning a decent bit of money. And then came the most eventful year of Einstein’s life: 1905.

The year 1905 is called Einstein’s annus mirabilis, or “miracle year”, because he released 4 papers, all of which deserve a Nobel Prize in Physics and that cemented him in the academic world.[1] The first paper outlined in detail the photoelectric effect, or the interaction of photons with electrons; essentially, he postulated that when photons hit metal, some electrons were knocked off, and that the amount depended on the intensity of life. Einstein didn’t know it at the time, but he had accidentally contributed to the creation of the field of quantum mechanics.

The second paper described the Brownian Motion of atoms. This might not seem to be a big deal, but it actually established much in physics; Einstein was not only able to prove definitively that atoms existed (a contested matter in that time of history), Einstein was able to describe the velocity, shape, size, and weight of the atoms.

The third paper was a paper that you might be more familiar with: Special Relativity. Now, the epithet “special” does not mean that this paper was more complex or better than general relativity; in fact, it is the opposite. Special relativity is the motion and interaction of space and time in a flat plane with negligible effects of gravity. It takes two postulates as its foundations: first, that the laws of physics were invariant, and second that the speed of light in a vacuum was the same for everyone. I’m not going to explain the entire theory here but keep an eye out for it in some future blog posts!

The fourth and final paper that Einstein published in this miracle year outlined the relationship between energy and mass to create what people have called the most famous equation in the world:

E = mc2

This seemingly simple equation has much darker implications. It states that the energy of an object is equal to its mass multiplied by the speed of light squared. Now, the speed of light in and of itself is an enormous number; it is impossible to conceive how big it squared would be! Einstein realized much later that this meant that even the smallest objects, such as a grain of sand, could release enough energy to light up an entire city for a year. This realization led to something that Einstein would regret all his life—but we’ll get to that later.

After this miracle year, Einstein did not achieve immediate fame. Perhaps because he was so young, or because he was a Jew, or because they didn’t understand his theories, a few of the scientific community did not agree with his ideas and tried their best to prove them wrong. Of course, their efforts were in vain, because Einstein’s theory has been validated several times with modern technology; at the time, however, it created an atmosphere of insecurity that was compounded by the onset of the First World War and the challenge he faced: creating a General Theory of Relativity.

Finally, in 1915, Einstein finally cracked the problem of General Relativity in a landmark paper that was able to accurately describe gravitation in terms of the curvature of space-time. Along with this paper came the famous Einstein field equations, 10 revolutionary equations that mathematically described the shape of the universe and the motion of objects on the fabric of space-time. It was the biggest achievement to date of any scientist; no one in the past had even come close to creating an accurate model of the universe that not only fit all observations but was also mathematically elegant and could describe precise motion of objects in space.[2] Even after this enormous scientific breakthrough, however, Einstein still had his detractors. In this case, however, Einstein finally had an opportunity to disprove them.

Einstein’s theory mathematically described the bending of light through space-time as photons curved when influenced by a gravitational field. This idea was ridiculed by many scientists as they believed that light would always travel straight. In order to prove it, Einstein’s close friend Arthur Eddington led a team of scientists to a solar eclipse in 1919; if Einstein’s theory was right, the light of stars would be bent by the sun during the eclipse and would appear in different positions. And, of course, Einstein was right; when the stars around the sun were observed, it was apparent that they were in different positions than they should have been; the sun had indeed bent the light around it.

This is what truly made Einstein famous to the rest of the world. While no one understood the theory, everyone understood that it was a ground-breaking idea that had revolutionized physics and our world outlook forever. Einstein was showered with felicitation everywhere that he went; his talks were often filled with journalists who wouldn’t understand a word he was saying (and wrote the same down later). Einstein’s appeal extended from just his scientific genius; he was also a nice person with a quirky sense of humor and a disheveled experience that endeared him to the public.

Incidentally, the rest of Einstein’s life was not as glorious as the first half. He spent much of the next thirty years trying to disprove something that he had, in fact, helped create: the theory of quantum mechanics. When Einstein returned to the quantum field, he had discovered, to his horror, that contemporary physicists now believed that nothing could be determined for sure, and that everything was “fuzzy”. Heisenberg, a physicist at the time, postulated his famous uncertainty principle: “the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa.” Essentially, it is impossible to determine the exact location and velocity of a particle at the same time.

Einstein absolutely hated this idea. His view of the universe was systematic order and clear understanding; it corresponded with his view of God, that God would want everything to be as simple and clear as possible. All this uncertainty that surrounded quantum mechanics enraged him to a point that he famously commented that “God does not play dice.” He would, inconclusively, work on finding an alternative unified field theory for the rest of his life.

What Einstein regretted the most in his life, however, was a letter that he signed that was sent to the then President Franklin D. Roosevelt. It stated that based on Einstein’s famous energy-mass equation, a small amount of matter could release an enormous amount of energy, and that this energy could be harnessed as a bomb of immense power and of a scale that had not been seen in the world before. Einstein found it necessary to let Roosevelt know because he was worried that the Germans would develop the bomb before the Americans; he regretted it later, however, when two atomic bombs were used on the Japanese cities of Hiroshima and Nagasaki in 1945. Einstein was a firm pacifist, and it shocked him deeply that his ideas had been used to murder millions of innocent civilians.

After the war, however, Einstein’s health began to deteriorate. He wasn’t taking very good care of himself and was coming upon bouts of forgetfulness. He began to suffer from aneurysms and was prone to illness; eventually, on the 17th of April 1955, he suffered such intense internal bleeding from the rupturing of an aneurysm that he passed away the next morning at the age of 76. He had been working until his death.

Einstein’s legacy continues, however. He inspired an entire generation of physicists to embrace thought experiments and the extraordinary and to rebel against what was the norm at the time; his ideas formed the most complete picture of the universe that we have had to this date. His entire list of achievements towers over all of us, and he will go down in history as the man who revolutionized physics and astronomy forever.


[1] He won a prize for only one of the papers, however.

[2] Interestingly, there was an additional portion in Einstein’s equation that he called the “cosmological constant”. It was a last-minute addition to reconcile the force of gravity; Einstein’s universe would otherwise have collapsed upon itself. Einstein hated this and for years afterwards called it his “greatest mistake”. When Edwin Hubble discovered the universe was expanding in 1929, Einstein promptly removed it from his equation. Now, however, it appears that we may still need the cosmological constant, as the universe is expanding faster that we had expected.


 Today in science: Edwin Hubble and the expanding universe ...Credit: EarthSky

When talking about Einstein, there are two more scientists that are in one way or another, inexorably linked to him. Edwin Hubble has the tremendous honor of having the first major space telescope named after him. Most people have heard about the telescope, but not many people have heard about the man it was named after, or what about his accomplishment warranted an honor as high as a naming.

Born in Minnesota in 1889, Hubble was a gifted athlete as a child. However, he also had a passion for astronomy that lingered from boyhood to his whole life. He attended the University of Chicago, and then attended Queen’s College at Oxford for another three years. A standard upbringing and education, it may seem surprising that Hubble’s discovery shook the roots of science to the core. And yet, it did.

What, you may ask, was so revolutionary about Hubble’s discovery? Essentially, Hubble’s observation of the recessional velocities of galaxies far from the Earth led him to the radical conclusion that the universe was not fixed or infinite as was the opinion at the time, but, in fact, it was expanding. This caused repercussions throughout the academic world as people hurried to check Hubble’s measurements and confirm his postulation; one person it significantly affected was Einstein.

Einstein’s field equations had the cosmological constant, if you remember, and he had put it in the equation to ‘counteract’ gravity. Upon realizing that the universe was expanding, Einstein promptly removed the constant from his equation, deeming it unnecessary considering that the expansion of the universe was already ‘counteracting’ gravity! However, modern measurements of recessional velocities have revealed that the universe might be expanding faster than we thought. We might still need Einstein’s cosmological constant after all…

Unfortunately for Hubble, despite his efforts to get astrophysics a recognized field by the Nobel committee, he passed away before they included it in the Nobel Prize for Physics. It’s even sadder that the Nobel Committee included it just a few years after his death. If it were not for his untimely demise, he would have earned a Nobel Prize in Physics. His achievement and legacy, however, live on in a greater honor: having a telescope named after him.


Karl Schwarzschild | German astronomer | Britannica.comCredit: Brittanica

 Karl Schwarzschild was a German astronomer and astrophysicist who is famous for a couple of reasons; he was the first person to successfully solve all ten of Einstein’s field equations, and in the process, he predicted black holes, their size, their shape, and their properties. Oh, and did I mention that he did all of this while positioned at the brutal Russian Front of the First World War?

Schwarzschild was born in Frankfurt on Main to Jewish parents. When he was young, he showed inclinations of the successes that he would achieve later in life; before he was 16, he had two published papers on orbital mechanics of binary orbits. After another 20 years, he was already at the most prestigious position for an astronomer in Germany, while also a member of the Prussian Academy of Sciences.

Schwarzschild’s end came unexpectedly and prematurely because of the First World War. Even though he was 40, he still chose to sign up for the military owing to his nationalism and patriotic pride; he served in artillery divisions on the Western and Eastern fronts, calculating shell trajectories and even being promoted to the rank of lieutenant. Unfortunately, the strains of the war eventually took a toll on his health, and he died in 1916 at the age of 42 of autoimmune skin disease.

Schwarzschild’s legacy lives on in what we now call the “Schwarzschild Radius”, a fancy name for the event horizon of a black hole—or the point of no return. Schwarzschild was able to use Einstein’s equations and make a derivative that accurately mathematically modeled a black hole and developed the foundation for black hole physics that scientists like Hawking would develop later. He was, without a doubt, an essential astronomer to the development of modern black hole theory, and our insight of these mysterious objects—from mere hypothesis to the actual picture taken in 2019—is dependent on him.


 Credit: Harvard University

Chandrasekhar is one of the most prolific astrophysicists of the modern era. His work definitively changed the formal definition of stellar evolution, affecting several steps in the process. His research into white dwarf structures as well as life cycles resulted in the term “Chandrasekhar Limit” – or the largest a white dwarf can be – being coined after him. And he was awarded the 1983 Nobel Prize in Physics for his groundbreaking work in the field.

Chandrasekhar was born in Lahore, in what was then British-occupied India. His intellectual curiosity was generated from two sources in his childhood; his mother’s pursuit of intellectual development, and his paternal uncle, the Indian scientist and Nobel Laureate C.V. Raman, encouraging him to pursue an interest in science. As he flourished in high school and his undergraduate studies, the Government of India provided him with an opportunity to travel to Cambridge to pursue his graduate studies at Trinity College.

He achieved his doctorate degree for a thesis about rotating self-gravitating polytropes, or the solution to the pressure-density relationship in astronomical objects. His work on polytropes earned him a Fellowship of Trinity College; incidentally, he had believed he would not achieve the honor, and had gone so far as to renting an apartment at Oxford in preparation!

Chandrasekhar then moved to the United States, pushed away from the United Kingdom by the racism he experienced even in the highest circles of science. His work in the United States was far-reaching and diverse, from the study of stellar classification and structures to Brownian motion and its effects on orbital dynamics. His fame, however, came from a concept known as the “Chandrasekhar Limit”, or the number 1.44; in layman’s terms, it states that white dwarfs can only be up to 1.44 times the size of the Sun, no larger. This revolutionary discovery ensured his preservation in the annals of astrophysics for years to come.

Chandrasekhar passed away at the age of 84 in 1995. Throughout his life, he had made discoveries that rocked the world of astrophysics, forming the foundation of much of the stellar theory that we experience today. He also guided more than 50 students to a doctorate degree, inspiring the next generation to follow in his footsteps. He was, without doubt, one of the greatest scientists of our time.