Johannes Kepler,Johannes Kepler: God’s Mathematician,history of Johannes Kepler,about Johannes Kepler

                                                          
                                       

                                                             Johannes Kepler

                                            Johannes Kepler: God’s Mathematician

In the early 17th Century, a religious mandecided he was going to uncover the architecture of the universe itself. Using observations of the Heavens and a deepunderstanding of geometry, this man conjectured a world of harmonious design, where the secretsof God’s creation could be deciphered by anyone willing to use mathematics to lookfor them. In the course of his quest, this man managedto change our understanding of astronomy forever. His name was Johannes Kepler, and he wouldgo down as one of the greatest scientists to ever live. Born into a divided Europe, Kepler grew upduring a time of unfathomable change.

 Witchcraft trials, religious war, and a scientificrevolution were all pulling the continent apart. Yet Kepler managed to not just navigate throughthese changes, but to do so while transforming science. He discovered laws of astronomy, changed ourunderstanding of optics, pioneered crystallography, developed telescopes, and even wrote what’slikely the first work of science-fiction. Persecuted for his faith, misunderstood inhis lifetime, this is the life of Johannes Kepler, the man who discovered the secretsof the universe. Children of the RevolutionsWhen Johannes Kepler was born in 1571, it was into a Europe already reeling from twomajor revolutions. Half a century earlier, a man called MartinLuther had nailed his Ninety Five Theses to a church door, kicking off a century and ahalf of religious upheaval known as The Reformation.

Twenty six years after that, in 1543, theastronomer Nicolaus Copernicus had proved the sun didn’t orbit the Earth, but theother way around, triggering an even bigger upheaval known as Scientific Revolution. By the time Johannes Kepler first opened hiseyes, these twin revelations were causing Europe to strain at the seams. Not that Kepler’s parents could’ve imaginedhe’d live long enough to see those seams rip wide open. The boy was weak, sickly. A prime candidate in those hard times foran early death. And die he nearly did. Before he was even five, Kepler came downwith smallpox, a disease that left his eyesight damaged and his hands unable to properly function. Luckily, though, it didn’t kill him. Instead, Kepler lived through his illnessto see the sight that would change his life. The Great Comet of 1577 was so bright it madethe whole of Europe stop and gawp. Up in the Kingdom of Denmark, the astronomerTycho Brahe - who we’re gonna meet again in a moment - watched the comet pass and knewit would transform his life’s work. For young Kepler, though, the Great Cometwas even more important.

It was this event that would one day makehim into an astronomer. But only after some false starts. As a good Lutheran growing up in the HolyRoman Empire - a collection of several hundred states roughly analogous to modern Germany- Kepler wasn’t meant to be a mathematician. When he enrolled at the University of Tübingenin 1589, it was on the strict understanding that he would study theology, become a pastorand help spread Luther’s gospel. The fact this didn’t happen is due entirelyto Michael Maestlin. Maestlin is one of those figures basicallyno-one today can name, but who wound up changing history. Kepler’s mathematics tutor, Maestlin wasa private devotee of Copernicus - “private” because these were the days when saying thesun didn’t orbit the Earth could end with the religious authorities using you as anunwilling test subject for their shiny new thumbscrews. But when Maestlin discovered Kepler lovedastronomy, he broke cover long enough to lend him Copernicus’s De revolutionibus orbiumcoelestium libri vi. What Kepler read there blew his mind.

 In Copernicus’s heliocentric universe, Keplersaw not heresy, but the first glimpses of God’s harmonious design. For Kepler, this was his Road to Damascusmoment, the revelation that changed everything. From then on , he devoted his life to studyingthe stars. It was the start of a journey that would takehim not just across the Holy Roman Empire, but into more danger than this sickly teencould have ever believed possible. The Road to PragueIn 1594, Johannes Kepler received an unexpected letter. Now 23, Kepler was on the verge of graduatinguniversity. Despite his devotion to astronomy, he stillplanned to become a pastor, because that’s just what you did in the late 16th century. The letter changed all that. Sent from the Austrian city of Graz, it invitedKepler to come and work as a math teacher. And, just like that, Kepler was able to throwhis boring destiny away, and become the mathematician he’d always dreamed of being. Well, almost. Despite what the letter had promised, almostnobody in Graz attended Kepler’s classes. He was forced to take a second job as a calendarmaker just to survive.

 But what Kepler’s life in Graz lacked inopportunities, success, or happiness, it more than made up for with spare time. Spare time in which Kepler could ponder someof science’s most-pressing mysteries. Before Copernicus had come along and dynamitedthousands of years of human thinking, it was accepted that the planets were fixed to theHeavens, and that the Heavens rotated around the Earth. But now Copernicus had shown Earth was movingaround the sun, all sorts of weird questions had arisen. Clearly, Earth wasn’t fixed to anything. It was just kinda floating along. So what made it float? What made the other planets move? It was while daydreaming in one of his near-emptyclasses in 1595 that Kepler felt a lightbulb go ping! above his head. If the planets had a regular orbit aroundthe sun, then surely this was because the sun itself was affecting them with some kindof force. Today, we’d call that force “gravity”,but Kepler was living about 50 years before Isaac Newton was even a lustful twinkle inhis father’s eye. So he called it magnetism.

Still, it was the first time anyone in Europehad even come close to understanding what made our solar system tick. But Kepler went even further than just pontificatingabout the sun. Curious about the space between the planets,he hypothesized that each gap must correspond to one of the Platonic solids: the tetrahedron,cube, octahedron, icosahedron, and dodecahedron. When his calculations seemed to bare thisout, he declared he’d uncovered God’s architecture. So, this might sound a little cuckoo to modernears. Magic shapes? God’s architecture? Whaaaa...? Well, we need to remember the era Kepler wasliving in. This was an era before pure mathematics. An era in which you could say the sun orbitedthe Earth and not only not have people snigger at you, but then have them imprison your neighborfor disagreeing. What Kepler’s work did was suggest the universecould be understood through math. That there was a scientific way of thinkingabout the Heavens beyond simply saying “God did it.” It’s that simple thought that would turbochargethe Scientific Revolution. Kepler published his ideas in 1597, the verysame year he married his first wife.

Not long after, he began writing to TychoBrahe. Remember Brahe? The Danish guy who saw the Great Comet andrealized it would transform his career? Well Kepler became his pen pal, just as Brahewas in the process of moving his work to Prague. It was a relationship that would soon saveKepler’s life. In 1599, the religious tensions simmeringacross Central Europe between Catholics and Lutherans boiled over in Graz. The city’s Catholics rioted, attacking Protestants. For the Lutheran Kepler, this was a “hoo,boy. Better get outta here,” moment. The trouble was, he had nowhere to go. His religious buddies back at Tübingen Universityhad read his book and decided he was a Copernicus-loving heretic who wasn’t allowed to hang out withthem anymore. Just as it was starting to look like Keplermight find himself being tarred and feathered by angry Catholics, Brahe threw him a lifeline. “Hey, I’ve got a crazy idea,” he basicallysaid, “why don’t you come work for me in Prague?” And that’s how, in the dying days of thesixteenth century, Johannes Kepler found himself joining the legendary court of Rudolf II.

The Court of the Golem If you were alive and into spooky stuff in 1600,there was nowhere better to be than Rudolf II’s Prague. The Holy Roman Emperor was obsessed with everythingoccult. The legendary alchemist John Dee worked forhim, as did Rabbi Loew, the man said to have created the Golem. Not that Rudolf distinguished between crackpotmysticism and actual science. He supported alchemists and astrologers, buthe also astronomers and mathematicians. And one of those astronomers just happenedto be Tycho Brahe. Brahe had arrived in Prague the year before,to take the title Imperial Mathematician. His mission was to undertake a new set ofplanetary observations, and then create a table from the results that could predictwhere anything in the night sky would be on any future date. Such tables had existed before, but they’dbeen plagued by poor data. Brahe was determined to make the most accuratetable in history.

 Unfortunately, history is exactly what TychoBrahe was about to become. On October 24, 1601, Brahe died. Rather than halt his work, Rudolf II simplyhanded it to Brahe’s new assistant. Which is how Kepler suddenly found himselfnot just saddled with the title Imperial Mathematician and a difficult job to finish, but also withaccess to the scientific equivalent of magic pixie dust. In his lifetime, Brahe had been a guy whodidn’t like to share. Among the things he didn’t like sharingwere his astronomical observations, the most-accurate in human history. So when Kepler inherited Brahe’s work, healso got his hands on these observations. This data would be the key that helped unlockKepler’s greatest discoveries. For the next decade, Kepler slaved away inPrague, making new discoveries like a man possessed. In 1604, for example, his attempt to figureout the best way to observe an eclipse sent him down a rabbit hole that ended in discoveringhow light travels through the human eye. Remember in science class, when you firstfound out that the human eye actually projects stuff onto your retinas upside down and yourbrain flips the image the right way up again? Well, Kepler was the first to discover that.

He then used this work to design highly improvedeyeglasses. The same year he was working on optics, Kepleralso became the first to observe what he called a “new star” in the sky. Actually, we know now it was the last recordedsupernova in the Milky Way. Many years later, Kepler’s observation wouldhelp prove the Earth isn’t the center of the universe. A few years later, in 1608, he wrote Somnium- or The Dream in English - possibly the first work of science fiction. But it was the book Kepler published in 1609that really changed the world. Astronomia Nova grew out of Kepler’s observationsof Mars’s orbit. After tracing it across the sky for years,he finally clicked that the complex, twisting trail we see from Earth is because Earth isalso moving through space. By deploying what in the 1600s must’ve seemedlike an insane thought experiment, Kepler managed to show what Earth’s own orbit wouldlook like from Mars. From there, it was just a small step to provethat Mars’s orbit must be elliptical. It was the first time anyone had figured outwhat a planet’s orbit actually looked like.

 And it was from here that Kepler drew hisFirst Law: that the planets have elliptical orbits, with the sun as one of the foci. It’s also from here that he drew the Secondof his Three Laws, which is pretty difficult to explain, but basically gives you a wayto measure the speed any planet is traveling around the sun. As for the Third Law… Well, we’ll get back to that. When Kepler published these findings in hisAstronomia Nova in 1609, he impressively included all his raw data - today something that’sa given where science is concerned. At the time, though, it was almost like adare for his critics. A way for Kepler to say: “oh, you thinkI’m wrong, do you? Well you study the data then, and show mewhere I’m wrong!” The Astronomia Nova was a monumental achievement,one that cemented Kepler’s claim to greatness. Unfortunately, 1609 was also the moment Kepler’sworld finally began to split apart. The Religious ProblemBack in 1555, the Holy Roman Empire had managed to stop the continent exploding with somethingcalled the Peace of Augsburg.

After Martin Luther did his thing, the Empirehad transformed into a gigantic pressure cooker, with Catholics and Lutherans threatening tounleash Holy War on one another. The Peace had released some of that pressureby removing the requirement for states in the Empire to be Catholic. Instead, each territory’s ruler could choosefor themselves whether to be Catholic or Lutheran and no-one else would interfere. But the Peace was just a temporary fix, aquick release of some steam. Inside individual states, pressure was stillrising as the growing popularity of Protestantism collided with the often-Catholic elite. In Bohemia, the Catholic Rudolf II had triedto solve this by signing the Letter of Majesty. An attempt at compromise, it allowed Bohemia’sprotestant nobles to build their own churches and worship how they wished. Unfortunately, it was this very act of compromisethat would ensure the pressure cooker of Europe finally exploded into the Thirty Years’War.

Not that Kepler noticed any of this. As the new decade dawned, he was still beaveringaway in Prague, still making discoveries. In 1610, for example, Galileo used the firsttelescope to discover Jupiter’s moons Io, Callisto, Europa, and Ganymede - now knowas the Galilean Moons. Their existence was such a controversial discoverythat most people simply refused to believe it, claiming the telescope must be causingoptical illusions. So Kepler sat down and wrote another bookon optics, which not only proved Galileo couldn’t be seeing things, but also described how tobuild a vastly more powerful telescope. If it’s starting to sound like Kepler coulddo just about anything he put his mind to, you haven’t heard the half of it. The following winter, 1611, he was inspiredto do a short study of snowflakes. Not only did he become the first person inhistory to observe that all snowflakes are unique, the resulting pamphlet has been calledthe earliest work on crystallography.

 Anyone else out there feeling like an underachieverright now? But even as Kepler kept churning out discoveryafter discovery, storm clouds were gathering on the horizon. The same year that Kepler was writing aboutsnowflakes, Rudolf’s younger brother Matthias forced the Emperor to abdicate at swordpoint. From the moment he took the throne, the hardcoreCatholic Matthias made it clear that he wasn’t going to honor any letters giving legal rightsto Protestant scum. Suddenly, the Lutheran Kepler was living ina city that officially hated Lutherans. It was Graz 2.0. And, once again, Kepler had no way out. As 1612 got underway, Kepler began searchingfrantically for an exit from Prague. He wrote again to his old university, butthey were all like “Nah, sorry dude. We couldn’t possibly hire a guy who thinksthe Earth orbits around the Sun. People would think we were crazy.” If that wasn’t bad enough, that same yearKepler’s wife died of spotted fever. Just as Kepler was getting desperate, thecity of Linz came to his rescue. They would create the position of districtmathematician just for him, provided he used his time in the city to finish Brahe’s tables. With no other options, Kepler accepted. He got out just in time. Five years later, in 1617, Prague crackeddown hard on its Protestants. The churches opened under Rudolf II were closed,non-Catholics subjected to harassment. For a year, the Protestants tried to put upwith these indignities. Then, in 1618, they finally snapped. On May 23, a group of Protestants stormedinto Prague castle, grabbed three Catholics and hurled them out a high window.

The Defenestration of Prague is famous todaynot for its death toll - all three Catholics survived after landing in a pile of manure- but for what it started. The defenestration was the opening salvo inthe Thirty Years’ War, three decades of religious violence that would destroy centralEurope and leave over 8 million dead. And Johannes Kepler was about to get caughtright in the middle of it. War and WitchcraftIf we were to try and explain the Thirty Years’ War, it would take about, well, thirty yearsand leave us all with very sore brains. To put it in its crudest terms, just knowthat it was a religious war that quickly grew beyond religion, and would ultimately involvenot just the many states of the Holy Roman Empire, but also France, Spain, Sweden, theNetherlands, Poland, the Ottoman Empire, the Habsburg Lands, England, Scotland, Russia,and pretty much just any nation that happened to be passing by and felt like joining thisRoyal Rumble. Oh, and because the war was so big, so long,and so vicious, it also created the ideal conditions for outbreaks of plague, whichin turn created the ideal conditions for witchcraft panics, which in turn led to some of the largestmass-executions for witchcraft in human history. So, yeah. The Thirty Years’ War. Not a fun time to be alive in Central Europe.

Sadly, Central Europe was exactly where Keplerwas. By 1619, Linz - like Graz and Prague beforeit - was paralyzed by anti-Protestant riots. As a guest of the city, Kepler was allowedto stay. He and his new family - he’d married locallass Susan Reuttinger soon after arriving in 1613 and they now had three children - wereofficially protected. But unofficially? Unofficially, the family had to deal withprejudice every single day. In such circumstances, it’s almost a wonderKepler got any work done. Yet somehow he managed. That same year Kepler published his ThirdLaw, which states that squaring the length of any planet’s orbit - in other words,the length of its year - and dividing that by its distance from the sun cubed will returna constant number. It was a powerful mathematic insight. But it was also overshadowed by events inKepler’s life. Remember the book Somnium Kepler publishedback in 1608? The one we said might be the first work ofscience fiction. Well, we didn’t mention it at the time,but Somnium includes a little side story, one about a son who is a scientist, and amother who is a witch. In 1620, life began imitating Kepler’s artin the darkest way.

That year, Kepler’s own mother was imprisonedfor witchcraft. Witchcraft accusations during the Thirty Years’War weren’t to be taken lightly. This was the same era as the Wurzburg WitchTrials, in which hundreds of people were burned at the stake. Kepler knew he had to save his mother, sohe dropped what he was doing and returned at once to organize her defense. The resulting trial would eat up over a yearof his life. To hear the story now is actually all sortsof impressive. Kepler approached the case like he did hisscientific work, using a deep analysis of the raw documents to forensically examinethe prosecution’s claims. It was a battle between science and superstition. A case in which one side used rational arguments,while the other talked about demons and women turning themselves into cats. Incredibly, science won. After 14 months manacled in a cell, the threatof torture looming over her, Kepler’s mother was set free, thanks entirely to her son’sefforts. For Kepler - heck, for rationality - thiswas a huge victory. But it was one that came at a price. For over a year, Kepler’s scientific workhad been put on hold. The trial had also left him in dire need ofmoney, money the city of Linz wasn’t willing to pay. Not long after the trial ended, Kepler’sLinz home was requisitioned and turned into a troop garrison. In 1625, the Catholics running the city confiscatedhis entire library and forced his children to start attending Mass. Finally, in 1626, Kepler and his family leftLinz for good.

By now they were broke and on the verge ofdestitution. Ever the optimist, Kepler tried heading backto Prague and asking the treasury for unpaid wages Rudolf II had owed him, but they simplylaughed him out the city. It was a bleak time, not just for Kepler,but for the whole of Europe. But the astronomer wasn’t done yet. He still had one last moment of greatnessto come. Into EternityIt had been 1599 when Rudolf II first called Tycho Brahe to his court to prepare new astronomicaltables. This was years before Kepler described hisThree Laws. Years before his discovery of Mars’s orbit,before the Defenestration of Prague, before the Thirty Years’ War. In that time, Brahe and Rudolf had both died. The continent had split apart. But Kepler hadn’t forgotten what he wasmeant to be doing. Hadn’t forgotten the promise he made, solong ago. In 1627, Kepler finally published Brahe’sfinished tables.

 Known today as the Rudolphine Tables, theywere the most accurate tables for predicting the movement of the planets in human history. They were based not just on Brahe’s jealously-guardeddata, but also on Kepler’s own observations. In fact, his Three Laws were baked into theTables, underlying every calculation Kepler had performed. If his Laws were real, the predictions inthe Tables would be borne out. And, luckily, there was a major one comingup that everyone could check them against. In 1631, Mercury was scheduled to transitacross the sun. Sadly for our story, Kepler wouldn’t liveto see himself vindicated. On November 15, 1630, Johannes Kepler passedaway in the city of Regensburg. Around him, the Thirty Years’ War continuedto rage, a pointless howl of destruction consuming Europe. Even in death, Kepler wouldn’t escape it. At some point, a rampaging army destroyedthe cemetery he was buried in. The location of his body is now lost to history. But even as Europe tore itself apart, thefirst rays of hope were beginning to glimmer. In 1631, Mercury completed its transit acrossthe sun, exactly as Kepler’s Tables had predicted it would. With Kepler’s work clearly on the mark,it started raising questions, one of which would eventually come to greatly trouble ayoung British man.

 About fifty years later, long after the ThirtyYears’ War had finally ended, Isaac Newton found himself pondering Kepler’s Tables. If it were possible to predict the movementsof planets so accurately, there must be some force guiding them. Newton disagreed with Kepler’s theory abouta magnetic sun. So he set about discovering just what thismysterious force could be. From these musings would come the discoveryof gravity. But while his influence on Newton may be Kepler’sbiggest claim to fame, there are other ways his work lasted. Just take a look at Kepler’s Conjecture,a 1611 theory on the stacking of cannonballs that wasn’t proved until 1998, nearly 400years later. But perhaps the most important aspect of Kepler’swork is the thinking that underlay it all. Kepler was one of the first to look at thenight sky and see not some unknowable mechanism at work, but a divine plan that was both beautifuland capable of being understood by humans. While Kepler may have been more explicitlyreligious than most scientists today - he actually referred to himself as a prophetat one point - that idea of a universal language, of an existence we can understand throughmathematics, is still relevant. Kepler may have died before he could see hislife’s work be proved right. But his name will continue to echo acrosshistory for centuries to come.