How the Bizarre Path of Mars Reshaped Astronomy [Kepler's Laws Part 1]

[@WelchLabsVideo]

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[@mikip3242]

Thank so much for this. I'm an astrophysicist and I can tell you that this kind of outreach is a must need. Very well done and very well explained. Kepler was an outstanding figure and getting to know the reasoning behind his archivement is beautiful.

[@Alexagrigorieff]

Would be nice to learn how Tycho Brahe is pronounced

[@Alexagrigorieff]

Also it's "died in vain", not "died in vein"

[@Alexagrigorieff]

It's "ancients" (anshients), not "ancshients"

[@bjorntorlarsson]

Why am I not allowed to leave any comments here? Having read Astronomia Nova, I've tried to say something about Kepler's pains with adjusting for the atmospheric refraction of stars' inclination. But none of my comments stick. I feel for unsubscribing. Do you btw copy your videos to Rumble that doesn't have random big government censorship of anything that might've "become politically sensitive" right now, who can guess what next, Kepler?

[@andersjjensen]

Kepler's quote about his own work is right up there with Sir Issac Newtons famous "This theory takes for granted a force that works instantly across infinite distances. Only a madman would belive such a thing" criticism of his own model of gravity that stood for 200 years before Einstein expanded it.

[@paradox9551]

All models are wrong, some are useful.

[@punchster289]

@@SahilGhosh no hes right

[@EvilDudeLOL]

​@@paradox9551 I don't give a damn what anybody else thinks, you are absolutely correct. (I believe I heard a similar quote from a famous scientist)

[@vikraal6974]

There are two more underrated quotes from Newton. In one quote he says if Gravity works on masses why can't gravity bend light? He was open to the view that light "a massless" entity could be affected by gravity.

[@andersjjensen]

@@paradox9551 That is a fundamental axiom of the scientific method. You make observations, then you build a model, then you make predictions based on that model and go test them. The model that violates the least observations is accepted until something better comes along. Today we are at the point that most models are perfectly adequate for all engineering work, outside the scientific endeavour of building new scientific instruments to further advance physics. That makes most models either useful, very useful or completely indispensable to our everyday lives.

[@enque01]

When you said "you'll have to wait until next episode for that" i was like "nooooooooo! I can't wait!"

[@sa-rq2xj]

Same! I literally said "Nooooo" out loud, even though I know the math, I have not heard this history in so much detail before. I can't wait for next time

[@wjrasmussen666]

No, I won't watch.

[@GlorifiedTruth]

Same here!

[@TheRmbomo]

I was counting on hearing the word barycenter as soon as the 'equant' idea came up. I had a similar reaction when the episode ended.

[@bjorntorlarsson]

Kepler's Astronomia Nova is freely available as a PDF file online. In its one and only translation to English in 1939. 330 years after its original publication. I suppose because only by the 1930s enough Englishmen had become uneducated enough to no longer be able to read the original. It is quite readable even today. And Kepler uses some sense of humor in it as he describes his laborious process with its setbacks and sudden insights. It is written at the time of Shakespeare! People wrote in an accesible way back then.

[@Spark_Books]

Nobody has ever explained Kepler's discovery process in this much detail ever before. All textbooks and videos just gloss over it and skip to the final result. Thank you for this wonderful work :)

[@Maxflay3r]

So basically, Kepler performed a manual gradient descent to find the right parameters for his model, lol.

[@WelchLabsVideo]

Yeah basically!

[@miepic3291]

1. ignores greek philosphers 2. ignores incorrect church based models 3. manually does gradient descent for his own model 4. still admits the model is wrong 5. steals his late boss' documents to remodel the entirety of astronomy 6. ends up being right Kepler is such a chad

[@bjorntorlarsson]

​@@miepic3291 And he complained about Tycho Brahe having used an unsuitable coordinate system (or however it was) forcing Kepler to recalculate every obseravtion adjusting for the atmosphereic refraction, depending on the inclination of Mars and the stars the angle of which its position was measured to. Before even making the data "raw" for his purposes. He complained much about the endless calculations. But his moment of truth was when the same number turned up more than once. Turned out to be the difference between Mars perihelion and aphelion! As I remember reading him, it was the repeating number that got him intrigued, before he realized what it could mean. Writing down figures in tedious calculations day and night. Getting a bit funny in the head and imagining a pattern in the mess. And it turns out to be something real! Later someone wrote him asking him to do the same for Saturn: "- F_ H_ No!! Go F_ Yourself!" /K

[@peterfireflylund]

@@miepic3291he also wrote a science fiction story + his mother was accused of witchcraft.

[@nuance9000]

​@@miepic3291Copernicus has entered the chat 😂😢

[@timoooo7320]

I find it astonishing that Kepler came up with the laws of planetary motions BEFORE the invention/discovery of calculus 🙌🙌🙌

[@brendawilliams8062]

My guess is people where actually involved in calculus but defining it as a form was not sought for

[@josepereira4372]

Johannes Kepler is my favorite machine learning algorithm.

[@richardbloemenkamp8532]

Does ML include Steepest-Descent, Newton-Raphson and Fixed-Point-iteration too now? That makes ML is a pretty big umbrella-term. We used to call those iterative numerical methods as opposed to analytical methods in mathematics.

[@quinius173]

@@richardbloemenkamp8532 Yes, machine learning has become a very broad term now.

[@mostlyokay]

@@richardbloemenkamp8532 I think he is referring to Kepler's brain

[@razbender1379]

​@@richardbloemenkamp8532 given that he lived before calculus, no

[@shrayesraman5192]

​@@richardbloemenkamp8532 I mean regression is considered a ml concept so sure this is done by a machine would probably qualify as it learns the weights

[@EloSportsTalk]

Kepler BRUTE FORCING his Mars calculations is kinda badass

[@siquod]

Newton wouldn't have needed 70 iterations, he converges quadratically!

[@LouieCastillo-l2x]

youtube tiktok twitter didnt exist back then

[@vast634]

Thats actually how I would image to have solved that. Finding an algorithmic way to the same conclusion is a later step.

[@QuantumHistorian]

You should look up Le Verrier's manual calculation of the precession of the perihelion of mercury. He solved the N-body problem of Mercury's orbit around the sun _by hand,_ using perturbation theory to solve the otherwise unsolvable problem. He did this to such an accuracy that he found an error of half an arc minute per century. He didn't believe Newton was wrong, so he spent a decade painstakingly redoing his maths, only to get the same conclusion. Astronomers then spent decades looking for (and convincingly themselves) that they'd found a new inner-most planet whose gravity would explain the discrepancy. Of course, we now know there is no such thing, and it was in fact the first direct experimental observation of Einstein's General Relativity.

[@exoplanet11]

What do you mean 'kinda'? Even doing this w/ a calculator would be such an onerous task most researchers would give up.

[@Thepineapplemonk]

This is so cool! The idea of doing all this by hand without any digital instrumentation or computation is incredible.

[@05degrees]

@@busimagen Well maybe not all the time in this case! It’s not that hard to figure out (moreso if it’s okay to figure it out to 90% and leave the rest for later) when you already have it and are a proficient mathematician. I hope. Also I hope in that situation the rule wouldn’t just fall from the skies but somebody could’ve been there and dropped a word or two. Or just logarithm tables which I think in our own history always came with instructions.

[@wayando]

Those guys were genuine geniuses ... And very patient too.

[@meltdown6165]

Brahe had his own instrument makers at his Uraniborg observatory, I bet that idea would have catched on quickely and be distributed around the scholars of Europe in no time. Edit: just looked up the history of the slide rule, it was invented about 10 years before Keplers death.

[@T0varisch]

I don't think you can do the second law without logs or living for centuries

[@ShieldAre]

Small mistake at 11:40: The years for Ibn al-Shatir should be AD, not BC. Excellent video, a very interesting explanation of the sort of measurements and reasoning that (I assume, discussed in the next video) ultimately led Kepler to arrive at the important missing conclusion from Copernicus' heliocentric model: The orbits of the planets are slightly elliptical, not perfectly circular. But I hadn't ever even heard about equant, and it surprises me, because of how close it gets to the idea of elliptical orbits.

[@frankmalenfant2828]

I named my cat Kepler. He thinks my life revolves around him.

[@hillaryclinton1314]

So.. feliocentric? I will let myself out...

[@Dhrumeel]

@@hillaryclinton1314 Bravo

[@dcamron46]

Yea but Kepler didn’t think life revolves him…he was not a geocentrist…?

[@frankmalenfant2828]

His theory postulates that attraction is equal to the quantity of food squared. He constantly lives in a quantum superposition of both fed and starving.

[@martalaatsch8358]

And not Schrödinger?

[@ЕгорБайченко-у1ш]

The question is why Moon was neglected in favor of planets. Distance to the Moon can be measured accurately both in relative and absolute terms by triangulation and apparent angular size and it completes twenty times as many revolutions than Mars thus accumulating observation data much more rapidly

[@keyofdoornarutorscat]

This is a good question. The main reason is that there is no “retrograde” motion of the Moon observed from the Earth (that was measurable with 1600s technology). This is in addition to the Moon’s low eccentricity which made it fit well with the idea of circular orbits (as opposed to non-circular ellipses)

[@Galenus1234]

Just a guess... To us it is quite straightforward that the same laws apply to all celestial bodies, because we know that for fact. Yet, to the naked eye of a 15th century astronomer the huge circular face of the moon looked nothing like those little wandering specks in the night sky, called "planets". So I can understand that noone even thought about going for the moon's motion first an then applying the moon's laws to the planets.

[@hareecionelson5875]

the moon orbits the earth and does not undergo retrograde motion the planets orbit the sun and so thye have weird paths through the night sky that people want to predict.

[@exoplanet11]

Also....you can't get Tycho's planetary precision with the Moon, since it is hard to spot its exact center, and observations at different observatories are impacted by lunar parallax.

[@ЕгорБайченко-у1ш]

@@exoplanet11 Impacted is the key. What impacts can taken into consideration ie gives us absolute value of distance in terms of feet.

[@FireRaptor100]

Whenever I searched for an explanation of the Kepler's laws I always found an explanation using the Newton's laws. I've always wanted to know how Kepler actually discovered his laws before differential calculus and Newton laws were invented. Thank you very much.

[@TazariaGaming]

I love the story from how we went from our ancient understanding of the planets to our current model of the Solar system. It spans thousands of years and so many brilliant minds. There is something beautiful about retracing those steps and watching our understanding of the universe evolve over time. Thank you for covering it! Very excited for the next video

[@m7mdyahia]

Ancient observation Potelmy Galileo Copernicus Newton Einstein Along with centuries of observation

[@jefflormans5441]

Superb production values. The use of clipped photos and quotes on 'aged' paper was stunning. Simple, easy, but unique and stunning. It amazes me how brilliant people like Kepler and Newton actually were. You tend to read about their achievements without realizing what they really involved. Thanks for doing this.

[@dominicestebanrice7460]

This is jaw-dropping good content; a masterpiece in the form. I've never seen such a complete yet concise exposition. And the integrated graphics are top-tier.

[@K0P]

Outstanding work! I love the vibe of these old-timey book illustrations. Kepler's crazy 3d frame looking thing MC Escher drawing belongs on a psychedelic rock album cover

[@WelchLabsVideo]

I should do a poster!

[@K0P]

@@WelchLabsVideo yes pls!

[@moneyheist_-]

​@@WelchLabsVideohave you looked into the the geocentric model proposed by Robert sungenis

[@jonr6680]

7:40 That right there is the money shot. The sublime animation graphics & explanation are the USP of this channel. Told me stuff I never knew (but which random dudes in C16 had figured out), and has the grace to actually break the complex geometry down to a level I can grasp. Should be mandatory in every school.

[@SBA_poiko]

Loved it! Really appreciate that all the animations are with a black background

[@kevcal7]

I've been waiting for this video for 2 decades. Thanks!

[@KalebPeters99]

Fantastic video, excited for part two!!

[@jmrm01]

I've read short histories of Astronomy several times. They all leave out, "Then Keplar stole a dead man's data..." But they did manage to mention that Tycho Brahe lost part of his nose in a sword duel, and wore a prosthetic replacement.

[@kadmii]

extremely excited for the next part. This is so much more complete and fascinating than most retellings that summarize and gloss over in order to get to the conclusions more directly

[@martinsanchez-hw4fi]

I would LOVE to learn the research process you go through to make these videos. Or become an assistant to collaborate. Total admiration for your amazing work

[@kenkiarie]

Fantastic story teller and oration. History motivated learning further enhances understanding. Thank you for the enlightenment!

[@peterwerrenrath1112]

Really clear graphics and story of the logic.

[@toadtws]

Oh my word, what a fantastic treatment of this subject. The animations are perfect at explaining these complex ideas. You’ve definitely earned a follower here. Bravo!! 🎉

[@tareksaid81]

It is so good to see you doing this awesome work Stephen. You have been a massive inspiration for my channel. Years ago I watched your "Imaginary Numbers are Real" series and it was a mind blowing experience. I realised after watching it that the best and most enjoyable way to understand complex topics is to study the history of their evolution. So I started reading about the history of different ideas and decided to make videos about them. Thank you for being such an inspiration and for continuing the great work. I am really looking forward to your next video!

[@LuisGLC31]

Hi Stephen! I've recently discovered your channel and I can honestly say that it blew my mind. The way you are capable of explaining complicated things in an easy-to-grasp manner, the overall quality of the visualizations, the books you show, and the stop-motion sections are all AMAZING. It has quickly become one of my favorite science channels, I've binge-watched most of your videos! It's not often that I comment on KZbin videos, but this time I just had to do it. Keep up the great work, mate! Oh, and as a side note, I really would appreciate it if you could take some time to put up links in the description to the music you use on your videos. I recognize some (mostly Satie Gymnopedies/Gnossienes), but I'd love to see a WelchLabs background music playlist :)

[@jowadulkader9006]

Unbelievably amazing story telling! Hats off sir!

[@ianmichael5768]

The Mechanical Universe indeed. Copernicus Kepler Jim Blinn You have made a beautiful film here. Thank you

[@nni9310]

Great video. Minor spelling error at 1:38: the expression is to not die in VAIN, not vein (which refers to were blood flows and minerals are extracted.

[@verymuchtom]

5:06 Hi to your cat! :)

[@edwardhuff4727]

Where is the cat? I looked carefully. 😥

[@therealpaulallen]

​@edwardhuff4727 you can hear it in the background

[@RobBon-hm8kr]

This level of detail is amazing, keep up the good work, subbed

[@feynstein1004]

I really enjoy this stuff because it provides much needed context behind historical advancements and discoveries. Unfortunately science is often taught like magic. No wonder people are skeptical. If someone tried to teach me the physics of 3024 AD without mentioning all of the advances from now until then, I'd be pretty skeptical too. Wait, I found a better analogy. It's like reading a research paper but everything except the conclusion is missing.

[@Silver8te]

having done a highschool course on astronomy that was basically just sides and worksheets, going into depth about kepler’s laws is extremely interesting and i’m already excited for the next ep

[@WelchLabsVideo]

Woohoo!

[@jaggerbushOG]

👏👏👏👏 this channel has been around for a while!

[@Thetarget1]

Amazing video! You are getting some details which aren´t even in Cosmos' explanation, which I always found the best of youtube. And now I´m so invested for part four! I teach physics, and I will probably be using this video in the future, at least for the more advanced students. It is also really fascinating how Kepler spent a year doing a computation, that a physics bachelor student with a basic knowledge of Python could do in an afternoon today.

[@BruceKoerner]

Wrong kind of vein. It should be "Don't let me die in vain."

[@Simpson17866]

Mayhap they were using the olde spelling? ;)

[@marcusdore7210]

Vayne

[@DanieleAGewurz]

@@Simpson17866 Tycho was a Dane who died in Bohemia: probably he didn't leave his last thought in English (olde or not).

[@Simpson17866]

@@DanieleAGewurz You didn't say "Um, Actually," so you get no points ;)

[@blueboats]

"... not to have died in vein" - clearly they did not have spell check for text graphics in 1601

[@bjorntorlarsson]

Tycho Brahe died on Ven, the small Danish island where he had his home and observatory.

[@koharaisevo3666]

@@bjorntorlarsson He die in Prague.

[@bjorntorlarsson]

@@koharaisevo3666 I know. The Swede's looted his grave during the 30 years war!

[@arleas]

It's "Die in vain" not "Vein" unless he's talking about his circulatory system.

[@davidgillespie9256]

Thank you, I wondered if I was the only pedantic person that saw this error. Oh no, my thought bubbles need spell and grammar checks.

[@mickelodiansurname9578]

@Welch Labs just to keep you up to date man your short about the Ptolemaic model is what drew me here... so the shorts are working. Subscribed

[@WelchLabsVideo]

Amazing thanks for the info - that really is helpful.

[@eswing2153]

That’s quite the cliffhanger. Thanks for making such great visuals.

[@brenorocha6687]

I usually dislike when we are told just at the end that the video is incomplete and left with a cliffhanger. But your presentation was so well done that instead I immediately subscribed. Great video!

[@ireoluwaTH]

Putting Kepler's picture on an elliptical frame is tight... 😉 Great videos as always!

[@ozimerman111]

Excellent. Thank you for doing this. Incredible amount of work.

[@LamirLakantry]

Techo was an exentric guy. Falce nose. Kept a pet moose which got drunk at parties, and died from not going to the bathroom for too long. What's interesting is that he had good reason from rejecting the heliocentric model. You see, if we went around the sun, then there would be parallax with the stars. There is though. But the distance was simply too vast to measure it with him equipment.

[@sujitchakraborty966]

I know I am nitpicking(sorry)... But at 1:35 he misspelt 'vain' as 'vein'

[@carmelwolf129]

really love your content. history of science is always so fascinating when told well, and you deliver!

[@MisterSnail1234]

11:11 bro had the chance to discover gravity but missed it instead💀

[@emiliocespedes3685]

These Kepler videos have me obsessed. They managed to do a lot with what we now would consider nothing, even if they sometimes made shit up.

[@jbflores01]

your video(s) is ,by far, the best explained and the videos convey the concept clearly! You do a great job on your videos!

[@MattGiuca]

Incredible research and explanation. Great work on the visuals, without which we'd be lost in the math.

[@christianhansen3590]

These history of science videos are awesome!

[@ShrekFishWT]

Cool ending

[@vivekpanchal3338]

In textbook, we often read , This or That scientist is great, usually we don't pay that much attention to it, because after that suddenly we get a well prepared meal of generalized laws by those, And there comes videos likes your, Which spreads lights on how struggle full this was for them to accomplish, Respect for Kepler,and for you to make such videos 👏🏻👏🏻👏🏻

[@wholesomejm]

This was an incredible video! Combinations of video and animation were stellar

[@jackspratnot1972]

Wow, im so glad i discovered your channel... This is some great, work thank you!

[@marcelma]

Wow, wow, wow! You don't only make science videos, these are pieces of art! AND you show that science always starts from how people think at the time, not from how people think after the discovery in question has already been integrated into everyone's thinking. - Extremely encouraging! Science basically turns out - again and again - to be the search for a pattern that makes all observable pieces really fit. Everyone can join from the however flawed thinking of their period with the perspective of breaking through to something better IF they are willing to to not give up until the picture of the puzzle comes into full view. No success guaranteed within one generation, but possible.

[@unvergebeneid]

0:59 Tycho Braaaah! 😄

[@aajmgopher]

…hay

[@unvergebeneid]

@@aajmgopher nah, brah. There was no hay.

[@XIIchiron78]

The way Tycho Brahe died is also pretty strange itself

[@PresidentPlayback]

Great video! 1.5x will squeeze this comfortably into a break and leave you wishing you were on lunch for part 2

[@tune490]

What! Left on a cliffhanger! I had read a little bit of this history before, but I didn't know the details. I can't wait for the next video!

[@Pherecydes]

The most important and incredible part of the Kepler story is that he had the wherewithal to scrutinize his original model, and after continuing to collect data, decided that his original model was mistaken and that a new model fit better. Today, the Platonic solid model would become accepted as "fact", hailed as "the most accurate and precise model of the solar system we've ever created", and scientific journals would all refuse to publish anyone else's alternative theory.

[@AbsolutZer0-1C3]

Man I subbed as soon as I saw the time lapse you did with Stellarium at the start of the video, very nice

[@WelchLabsVideo]

Thanks! Yeah that was a bit tricky!!

[@ghostedyoutuber263]

nice editing and visuals!, really helpful when showing noobs about frame of reference transitions.

[@Yitzh6k]

Frustrating that this only has 10k views a day in. All your videos are excellent.

[@Elchouse]

What a truly awesome video. Are the books you show (like in this one the Astronomia Nova) bought from somewhere or do you print and bind them?

[@WelchLabsVideo]

Bind them myself - wish I could buy them somewhere!

[@piviriccardo8397]

this video is fantastic! - love from an italian physics student

[@Martinko_Pcik]

Amazing what could be figured out even without the telescope

[@spirosskouras7587]

Honestly I feel like I found a channel similar to veratasium or VSauce. Rare but awesome and informative in an interesting way. Keep up the good work

[@PlayNowWorkLater]

Super interesting going through the logical development of his ideas

[@marccawood]

As a philosopher I love how this shows men of “science” fuddling about with arbitrary models till one fits then calling it a “Law” or “Reality”. At each point the accepted model is the scientific reality… until it’s superceded, not refined but completely overthrown!

[@carpemkarzi]

Excellent video

[@TazPessle]

Just found your channel from a short. Amazing high quality.

[@exoplanet11]

Here's one professional astronomer congratulating you on an excellent video. Well done. Looking forward to the next video and hoping to see the quote: "Ah, what a foolish bird I have been!"

[@kurttate9446]

Johann Kepler the Rodney Dangerfield of Astronomy. My favorite of all the early scientists.

[@DanjasLP]

Kepler going in and starting that second part of his book by claiming that everything he just explained is false, may be the greatest plot twist in the history of science communication.

[@tombouie]

Well Done, you're quite the astronomy-historian; It's quite unbelievable that people stuck on earth with little/no technology could figured-out how the planets moved millions of miles away. In the end, all motion is relative & sun-centered planet orbits just makes the math easiest

[@endlesswick]

This is very interesting. When I was in college I watched the Carl Sagan Cosmos episode about Kepler and I was really inspired. I made a POVray image of Kepler's first cosmological model.

[@SashiMurai]

For ESL speakers who may mishear at the beginning, he says "Wander" not "Wonder." Wonder (Wund-er) : To desire or be curious to know something. Wander (Wand-er) : to move in a leisurely, casual, or aimless way.

[@chaoticlue]

Awesome. I wish this could be converted to a series of sorts; a sub-channel maybe where you'd tell how things were discovered. It sure does have a long list, but an extremely interesting one at that.

[@swainscheps]

0:17 I had an ex from SE Texas who pronounced both wander/and wonder as ‘wunder’ too (If any were confused, planet is Greek for ‘wanderer’ not ‘wonderer’) Can’t help you on ancient as “aink-shent” though. Don’t think that’s a Texas thing… Cheers. Keep up the great work!

[@jurgkreis3427]

Wonderful video, I love it! Can’t wait for part two 😊

[@CDai-rw7sm]

Ahhhh all the custom visualization❤❤❤ Please also make a video about what laplace did with his perturbation theory and discovery of Neptune

[@hiongun]

Amazing channel. Amazing discovery process.

[@FreemindTv11]

I am totally no smart enough to completely get this, but it is endlessly fascinating

[@snowscape]

Great work

[@das250250]

This is a great video for a few more that are now possible. To retrace observations of mars ,to show how to collect the data. How to measure the data that's required and why . 2D and 3D models showing the angles , the devices these individuals used to make accurate measurements of that time. To show of were they using the same methods . Essentially ,to get into the shoes of these very brilliant scientists. To show the details of their models and math. You could do a complete series showing all of this.

[@animeniacthephysicist9557]

The return of the best youtube channel

[@veritasvita5672]

The geocentric model explains this with ease, all you have to do is to look it up

[@AngshumanBhardwaj]

Now that's a cliffhanger!

[@kennyhoughton]

This is easily the most interesting video I have ever watched on KZbin 100 billion out of 100 billion stars. Very good very very good. thank you so much.

[@maxwellduncan3555]

I'm also from Harris County!

[@rodrigomartindelcampo9534]

This feels like the prequel to the book “The Hunt for Vulcan” by Thomas Levenson, it just happens to be in video form! I had always had a sour feeling about being told that yeah Kepler measured and then he came up with his three laws, we can’t get really deep into that now. I’m so happy you are getting deep into that.

[@daniellomeli]

I can't wait for the second part

[@diegoguzman4307]

Thank you for this beautiful explanation ❤❤❤

[@Krom-fk3me]

could Kepler have found the angles between the sun and mars without cleverly using the points where the sun and mars were in opposition?

[@nathangale7702]

Thanks, I think this will be helpful for my physics students next semester.

[@johneagle4384]

Both are amazing: The video and Kepler. Thank you.