The New Astronomy: Crash Course History of Science #13
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The New Astronomy: Crash Course History of Science #13


Heliocentrism was central to revolution in
European astronomy. We’ll follow this idea to its conclusion
with Galileo. But before we get there, there are two critical
links between Copernicus and Galileo. This is the story of Tycho Brahe and Johannes Kepler… and a violent math duel. [INTRO MUSIC PLAYS] There are a lot of quirky characters in the history of science. But Tycho Brahe is a true champion of quirk. Traditionally referred to as “Tycho,”
not by his last name, he was a Danish aristocrat, born in 1546—three years after De rev dropped
and Copernicus also dropped. Tycho was a good astronomer. But maybe a little too serious about knowledge:
my dude got his nose cut off in 1566 during a sword duel with his cousin and fellow rich
person Manderup Parsberg. Their beef was—wait for it—over mathematics. You have to really love math to lose your
proboscis over it. After the duel, Tycho had prosthetic noses
made that he could attach to his face with wax. But whenever he got angry, he’d heat up
and start sweating, and the wax would melt… and his nose would fall off. …that’s real. In addition to an astronomer, Tycho was an
alchemist and astrologer. He became so well known as a scientist that
the Danish king kept trying to give him castles so he wouldn’t move away. And Tycho kept turning down castles—until
he got his own private research island, Hven On Hven, Tycho built two structures, Uraniborg, or the Castle of the Heavens, and Stjerneborg,
or the Castle of the Stars. Together, these castles represented the most
state-of-the-art research labs of the day. Here, Tycho built a scientific empire. He had his own printing press, paper mill,
alchemical equipment, and—most importantly—huge, expensive instruments and an army of staff
scientists working for him. In fact, Tycho worked with his younger sister,
Sophie. Tycho and his staff produced some of the most
precise naked-eye observations of the night sky ever. These were roughly twice as precise as similar
observations by ancient Egyptian, Babylonian, and Greek astronomers. Tycho’s observations were not surpassed
by those made with telescopes for a hundred years. Tycho believed in a geo-heliocentric cosmos. In this model, the sun orbits the earth, but
the other planets revolve around the sun. So Tycho was moving away from Aristotle and
Ptolemy. And his hybrid model actually solved a bunch
of the math problems astronomers were having with the Ptolemaic model… But it also placed the sun on a collision
course with the planets. So, not perfect. Even if the Tychonic model of the solar system
had flaws, his observations paid off in other ways. Tycho observed and took precise measurements
of the same sky all the time, noting that sometimes “stars” streaked around—these
were comets. In 1572, he saw a nova stella, er, a new star,
which we now call a supernova. He noted that this new star didn’t have
a tail or show any stellar parallax, meaning an apparent shift in position against a background
of distant objects. This meant that the new star had to be really,
really, incredibly far away—a true star and not a comet. Moreover, the appearance of a new star meant
that the heavens could change! God could straight up add new stars! If you really believed your whole life that
the heavens were perfect and unchanging, how hard would it be to adjust those beliefs just
because you saw one new dim little pinpoint of light at night, a dot that nobody else
cared about? That’s just what Tycho did: one year after
the supernova, in 1573, he dropped his own book: De nova stella, or On the New Star. But after all that hard work, Tycho’s life
ended sadly. The old Danish king died, and his nineteen-year-old
son took over. This not-super intellectual new king wanted
his nobles to spend their energy on war, not science. So he roused up opposition to Tycho’s science
castles, whipping up a mob to drive the patient observer into exile. Thus Tycho moved to Prague, in the Holy Roman
Empire—where he died after only two years in exile, leaving behind an enormous meticulously
detailed catalogue of observable stars and one very well-trained assistant… Johannes Kepler was born in 1571 near Stuttgart,
Germany. His grandfather was rich, but his dad hadn’t
done so well, dying as a mercenary in the Netherlands. Little Joey went to school on scholarship
at a Latin school, seminary, and then the University of Tübingen. Which is still a great school today! Go, uh, ‘Bingers!? After college, Kepler taught math. Then, in 1600, Kepler so impressed Tycho that
the older astronomer shared his secret data sets with him, and the two become close collaborators. Then politics happened: Kepler, a devout Lutheran,
was told to convert to Catholicism or leave Prague. Kepler—who used to call himself a “mangy
dog” because he was so full of self-doubt—chose exile. When Tycho died in 1601, however, Kepler was
immediately ordered to serve as the official imperial mathematician and continue Tycho’s
work. Politics! Make up your mind! As imperial numbers person, Kepler mostly
provided the emperor with advice about astrology. Remember that astronomy was seen as the less
useful, theoretical cousin of the practical art of astrology. But Kepler, thank goodness, kept making time for astronomy. In addition to the observing and cataloguing
that he’d done with Tycho, Kepler worked on optical physics. And he observed a new supernova in 1604, in
the foot of a constellation that is supposed to depict a Greek dude fighting a giant snake! (Or just holding it. We aren’t sure.) Kepler wrote his own De nova stella around
1605. But Kepler is famous thanks to the laws governing
how planets move. Kepler published Astronomia nova, or A New
Astronomy, in 1609. This mind-zapper of a tome came from a decade
of looking at Mars to figure out mathematical formulas that could predict its movements. ThoughtBubble, show us the Red Planet. Kepler calculated many versions of Mars’s
orbit using an equant point: this was an imaginary point in space that Copernicus had already
figured out how to get rid of. Using an equant, Kepler made a model of Mars’s
motion that almost fit Tycho’s crazy-meticulous data set of years of observations. Almost. Kepler didn’t just want a close model; he
wanted to understand what was happening up there. So he threw out his earlier models… and
tried an elliptical or ovoid orbit with the sun in the center. And, in writing up his Mars study, he proposed
the first two laws of planetary motion. The first law states that every planet has
an elliptical orbit, with the sun at one of the two foci of the ellipse, not its center. The second law explains that, even though
the speed at which a planet revolves around the sun will vary—because the planet will
travel faster when it’s closer to the sun—you can still figure out a constant speed for
the planet, called an area speed. This is the area described by the little pizza
slice shape made when you draw a line from the planet to the sun at time 1 and then again
at time 2, whatever those times are, and then fill in the area between the lines. If you do this again later in the planet’s
trip, with the same interval between time points, you’ll get a slice with the same
area. Sounds complicated, but it was important for
showing that planets do actually move at non-uniform speeds—and yet we can describe these motions
very precisely using the right mix of math and patient observation of the night sky! Thanks Thoughtbubble! Kepler didn’t write the third law until
1619, by the way. It explains the relationship between the distance
from planets to the Sun and their orbital periods. This law was Kepler’s attempt to explain
the harmony of the “music of the spheres!” Alright, so that might not make the best scene
in an action movie: Kepler stops using an imaginary dot to make circles move like eggs,
and instead just draws a dang egg. But this represented a clear break with Aristotle
and Ptolemy and a millennium of Christian thought. And Kepler, unlike Copernicus, didn’t hold
back his theory for fear of ridicule by his peers or condemnation by the Church. In fact, religious ideas helped Kepler move
toward a heliocentric, eccentric model: he saw the sun as a symbol of God the Father,
at the center of things, moving planets faster when they came closer. So when Kepler plugged the Mars data into
his new model, and the numbers worked out, he probably didn’t rejoice at the triumph
of secular thought over faith. He rejoiced at a harmony of ideas: his faith,
empirical data, and elegant math—all in sync! Kepler gave European astronomers a theory,
backed by superb math, that explained natural phenomena better than Aristotle, Ptolemy,
Oresme, Copernicus, and Tycho could. (Although Kepler built on work by all of them—science
is a team sport!) But the most famous astronomer from this period
gave astronomers a true research paradigm—ways to do science all day. You might know Galileo Galilei, born in 1564, as the person who dropped stuff off the side of a messed-up
tower in Pisa. If you recall episode one, though, you know
that Galileo probably didn’t conduct this experiment: the first published account of
it dates from 1657, fifteen years after Galileo died. And Galileo worked on this theory a decade
after he left Pisa. That said, he did prove the uniform rate of
falling bodies. And Galileo did lots of other amazing things
for science, earning him uncontested rockstar status. We’ll learn more about his overall contributions
next week. Right now, let’s talk star-gazing. First, Galileo got his hands on a telescope
in 1609 and refined this technology for years, which led to more and better observations
of distant planets. In 1610, he dropped Sidereus Nuncius or The Starry Messenger – what a very good title for this book – which was his telescope-enabled
description of the earth’s moon and the “stars” orbiting Jupiter—which were its moons. His descriptions were based on literally never-before-possible
observations and included accurate illustrations showing mountains on our moon. And these were good drawings, because Galileo
had been trained as a professional artist! And, according to Aristotle’s cosmology,
a planet could not orbit another planet other than earth. So Sidereus Nuncius represented an empirically
based break with the older model. Soon after, Galileo went on to make precise
observations of Venus, Saturn, and even Neptune. Neptune was ultra-dim through the lens of
his telescope, a mere thirty-times magnification compared to the naked eye. The best was yet to come. In his Dialogue Concerning the Two Chief World
Systems of 1632, Galileo explained the new astronomy of Copernicus to a wide audience. And he did this in terms of a debate within
science about what counts as good evidence. That is, Galileo saw the birth of a new scientific
paradigm as revolutionary! Galileo argued publicly with geocentrists
and believers in Tycho’s hybrid model. Galileo argued that the tides demonstrate
that the earth indeed moves, and that Copernicus’s model is right. Saying that, as the Earth moves, the oceans slosh around on its surface. He didn’t get everything precisely right. Interestingly, Galileo knew about Kepler’s
theories but didn’t seem interested in them. Unfortunately for Galileo, the Church also
saw his work as revolutionary. The Inquisition banned him from publishing
any new work. But Galileo eventually found
a Dutch publisher for his magnum opus, Two New Sciences. Published in 1638, it would become one of
the foundational texts detailing a new scientific method… Next time—we’ll dive into Galileo’s
thoughts about how to do science and meet two other key scientific methodists, Francis
Bacon—who was not also Shakespeare!—and René Descartes. Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney studio in Missoula, Montana and it’s made possible with the help of all this nice people and our animation team is Thought Cafe. Crash Course is a Complexly production. If you wanna keep imagining the world complexly with us, you can check out some of our other channels like The Financial Diet, Scishow Space, and Mental Floss. And, if you’d like to keep Crash Course free for everybody, forever, you can support the series at Patreon; a crowdfunding platform that allows you to support the content you love. Thank you to all of our patrons for making Crash Course possible with their continued support.

100 thoughts on “The New Astronomy: Crash Course History of Science #13

  1. We must be skipping much time to meet these Scientific Methodists, as their church was not founded 'til the 1700s. :p

  2. Wouldn't the conclusion of the idea of helocentrism be with Newton who derived Keppler's laws via calculus and unified physics and astronomy?

  3. Dear Hank,
    please learn how to pronounce the names of German university towns. This video was almost perfect, only the "toobinjen" threw me off.

  4. "but poor Galileo got locked away
    to whither and rot until the end of days
    and the moment comes when we might break through into the light"
    -super science friends

  5. Thinking how crazy it is all the galaxies out there with supernovas going off all the time, and we wouldn't even notice it from this distance, with the naked eye. 🤯

  6. Oh good lord I’m currently doing my PhD in Tübingen and the way Hank pronounced it is making me howl 😂😂😂

    It’s: two-bing-ngen ☺️

  7. Yay, loved it! I hope you guys do the history of electricity soon! I watched a documentary a few years ago that I was never able to find again, I think it was called just that: The History of Eloectricity. Would love to remind myself of all the steps taken!

  8. I think we should always use pizza to explain complex scientific ideas. It would make people pay attention.

    There's this great video of John Oliver trying to explain to random people how the data Snowden leaked shows the government can spy on them (nobody cared), and then explain the same thing again in the context of "how does that technology help the government steal pictures of your junk", to which the same people reacted much more strongly, now that it was a real thing they could comprehend and now just a mysterious acronym.

  9. You should have specified that Galileo did not recognize Neptune as a new planet. He just thought it was an ordinary star and recorded its position near Jupiter during one of his many observations of Jupiter's moons.

  10. Galileo's theories were, however, considered flawed, especially mathematically. Then there's the fact that he not only denounced geocentrism, theory favored by church, but ridiculed church for supporting it. In fact, I would go so far as to claim his biggest contributions were to earthly physics, not astronomy…

  11. Uh oh my nose is feeling loose… Galileo didn’t show that bodies fall at a uniform rate but at a uniform acceleration…

  12. All you need now to make this the Ultimate Learning Channel is #1 Get some Vsause who teaches Science & Technology, #2 Salman Khan, the founder of Khan Academy, one of the greatest minds for learning math from Kindergarten-Collage, Anyways I hope you Really consider doing this, Or at Least doing a Collab! Well that's all, Love you vids!! Much love <3 <3

  13. It makes me wonder, among the flat Earth crowd who are so convinced of their name sake, how many also believe Earth is still the center of the solar system? Have these people been keeping their belief secret from their more scientifically minded flat Earth peers? Why hasn't there been a Earth Center movement in the US?

  14. For some reason after hearing about Tycho's nose incidents I can't get the picture out of my head of Michael Jackson throwing his nose at haters

  15. Can we collectively agree that the idea that Copernicus or Galileo were persecuted primarily for religious reasons is debatable at best? That comes from a series of "just so" stories made popular in the early to mid-twentieth century. In actuality, the whole thing is a lot more complicated. At the risk of this being too late for anyone to notice, I'll go ahead and explain what I mean below:

    To be clear, this does NOT mean that Galileo wasn't persecuted by the Church, but in pre-Napoleonic Europe the Church was a mix of both religious and political force. In other words, sometimes activities done by the church were solely driven by politics and power and less so than personal belief (even less so, religiously held belief). This is, in part, a reason that Enlightenment philosophies, particularly those of Locke (and thus the influence upon the USA) emphasized a separation of church and state (that's not the only reason, but it is part of the reason).

    In fact, the work of Galileo had considerable support from many different groups within the Church at the time. The problem is that Galileo's ideas disproved Aristotle's principles. Aristotle's most famous and well liked (in Europe at the time) disciple was none other than the "dumb Ox" Thomas Aquinas. Thomas Aquinas was a Dominican, and though Aquinas was no longer alive at the time of Galileo, the Dominicans were a formidable religious and (more important for our purposes) political force within the church (and thus within Roman Catholic territories). There is no way they would stand by and let their beloved St Aquinas be tarnished, even if only by association, by some non-Dominican who disproved Aristotle. To be clear, others who were not Dominican did, at the time of Galileo, argue that a geo-centric model of the universe was not a tenant of any faith. Since as early as Augustine (mid-late 300s), there were strong arguments that, in his words, "only a fool would take Genesis literally." In fact the primary argument against Galileo from the Dominicans (other than their opposition to rejecting Aristotle) was to point to Joshua where he commanded the sun to be still. They argued that this was a Scriptural basis for saying that it was the sun and not the earth (for the record, the debate partner with this particular Dominican who initially used this argument literally laughed at such an absurd interpretation of the language). Eventually the Dominicans, over the objections of a respectable number of non-Dominican priests, canons, bishops, etc, convinced the Pope.

    The rest, as they say, is history. Don't believe, necessarily, the writings of one Andrew Dickson White (first President of Cornell), who in the late 19th century pushed hard for a narrative that saw Christianity as the great enemy of intellectual progress. That's where a lot of these theories began. It's not true (or at best, much more complicated), and many of the best pushes forward in physics and biology were funded, directly or indirectly, by the Church. (sincerely, not a Roman Catholic, but a nuanced fan)

  16. How did CrashCourse skip over how Tycho Brahe died? Dying from a bladder infection from a refusal to leave a banquet because it would have been rude is a… unique way to die. Like so many other parts of his life.

  17. Francis Bacon was a scientist? Wow, some how I had absolutely no idea. And I've been to his gallery!

  18. If you found the Tycho and Joahannes story interesting, and if you haven't already, I urge you to watch the episode of the originial Cosmos on this topic. Some of these stories deserve a movie or an HBO series or something, I swear.

  19. How can you be such a fan of science and people who want to help and such a d!ck to Elon Musk at the same time? Dont you realise you are on the other side of what you adore when you do this?

  20. I am currently taking a summer semester class of exactly this subject-matter and this playlist has been immensely helpful, aiding in my comprehension of events, philosophers/cosmologists, and their beliefs. I can not talk you guys enough. Can't wait for the 14th video to drop!

  21. Tübingen is pronounced similar to "to" + "begin", with the emphasis placed on the "to". So, Tü-bing-en ("bing" like the MS search engine).

  22. You missed the most important part: Tycho rejected Copernicus model because it didn't fit the data he measured. Hypothesis rejected by experimental data.. Kepler then expanded on the hypothesis and found a model that did fit.

  23. This is history of only European Astronomy and not world Astronomy. No mention of Indian and Egyptian contributions!! Worth googling "Sulbha Sutra" and "Surya Siddhanta" which are ancient Indian texts writtens over 2000 years ago giving accurate measurements of earth's circumference, distance from the moon, etc.

  24. Religions r just terrible i hope someday natural selection would redeem stupid ppl what a shame science got delayed and fought against for the sake of religions i just don’t get how they’re still around

  25. I know it doesn't have anything to do with science stuff, but how can you talk about Tycho without mentioning his pet moose with a penchant for beer? The man got a moose drunk at parties for fun!

  26. Good kings know to keep the brightest scientist alive and well at any costs. Tycho was given castles after castles so he would remain under the king, and later Mendeleev was pardoned by the Tsar just so he can keep his labs operating.

  27. Hey guys, does anybody know if those castles on Hven still exist? I only heard about a whiskey distillery and a golf club.

    And hey, Tübingen has a great University indeed! Their books on German studies are the best ones nowadays!

  28. Galileo was only banned from writing after he went against an order from the pope to stop publishing books with little 'evidence' as the geocentric model had a lot of evidence at the time and was the accepted model by many scientists.

  29. You make it sound like Brahe and Kepler were close friends, but their relationship was quite complicated and antagonistic.

  30. So does anyone know if "Two-Ko" is the German or like an old Danish pronunciation of Tycho? I'm assuming it's the German version because grammar but I always thought that earlier forms of Danish also pronounced Y like ü like it does in Old Norse. Nice vid though, has caused an existential crisis over the letter Y though

  31. huh? uranus and neptune weren't discovered until the late 1700's and early 1800's… are you SURE that galileo was drawing neptune in the 1600's? fact check plz

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