# What observations did Copernicus make that argued for a heliocentric view of the universe? **URL:** \ **Category:** Factual Questions\ **Created:** [October 10, 2022, 12:41pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010 "2022-10-10T12:41:34Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 11, 2022, 11:18pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/21 "2022-10-11T23:18:39Z")
> [@Chronos](#): > > (he [Galileo] wasn’t the first to make a telescope, but he does seem to have been the first to use it to make and record observations of the heavens). More accurately, he was the first to publish. There were other people with telescopes at the time and some also looked at celestial objects. For example, a guy named Simon Marius discovered the Galilean satellites at pretty much the same time as Galileo, but Galileo gets all the credit. Marius’ names for them ended up being accepted, though. ---
**Author:** ![JohnGalt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johngalt/32/184_2.png) [@JohnGalt](https://boards.straightdope.com/u/JohnGalt)\ **Post date:** [October 11, 2022, 11:30pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/22 "2022-10-11T23:30:34Z")
I’ve heard said that Galileo’s view of Jupiter and its moons wasn’t any better than what your binocular gives you, and was possibly worse. It does take a steady hand to get a good view. When my daughter was in middle school we used my telescope to watch Jupiter’s moons for a few weeks to see if she could predict which dot was which, and try to predict the next day’s positions (it was a science fair project). It was hard to do figure it which moon was which, so Galileo must have lots of fun. Another thing you should try when camping is to find the Andromeda galaxy, easiest in the summer. After finding it with binoculars, try to see if you can see it without aid. Seeing another galaxy with your naked eyes, and recognizing it as a galaxy _that you can see_ is mind-blowing. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 11, 2022, 11:44pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/23 "2022-10-11T23:44:08Z")
> [@JohnGalt](#): > > I’ve heard said that Galileo’s view of Jupiter and its moons wasn’t any better than what your binocular gives you, and was possibly worse. Much worse. Your binocs will give a nice wide field of view. Galileo’s telescope had a concave eyepiece, which makes for a narrow field of view. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 11, 2022, 11:48pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/24 "2022-10-11T23:48:37Z")
That, and his optics were much lower quality than what any modern device would use. Not bad for someone hand-grinding lenses and making up his own techniques as he went along, but technology has improved since his time. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [October 11, 2022, 11:58pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/25 "2022-10-11T23:58:04Z")
Galileo could barely tell that there was something funny about the shape of Saturn - but modern binoculars can see the Rings pretty clearly, right? ---
**Author:** ![gnarator](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gnarator/32/8266_2.png) [@gnarator](https://boards.straightdope.com/u/gnarator)\ **Post date:** [October 12, 2022, 12:45am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/26 "2022-10-12T00:45:57Z")
Really good ones, maybe, but in your standard 10x50 binoculars it looks oblong. You need about 30x to really see the rings. Galileo’s telescope was about 20x. ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [October 12, 2022, 3:00am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/27 "2022-10-12T03:00:03Z")
I’ve been told that he first thought it was a planet with ears. I’ve looked through a supposedly accurate reproduction of Galileo’s telescope. It was terrible. Very fuzzy, very narrow FOV. Hard to make out anything. (I only used it during the day, not at night.) ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [October 12, 2022, 3:44am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/28 "2022-10-12T03:44:16Z")
Here’s the summary in the Wikipedia article: > [@](#): > > He wrote to the [Duke of Tuscany](https://en.m.wikipedia.org/wiki/Cosimo_II_de%27_Medici,_Grand_Duke_of_Tuscany) that “The planet Saturn is not alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the [zodiac](https://en.m.wikipedia.org/wiki/Zodiac), and the middle one (Saturn itself) is about three times the size of the lateral ones.”[[5]](https://en.m.wikipedia.org/wiki/Rings_of_Saturn#cite_note-Whitehouse2009-5) He also described the rings as Saturn’s “ears”. In 1612 the Earth passed through the plane of the rings and they became invisible. Mystified, Galileo remarked “I do not know what to say in a case so surprising, so unlooked for and so novel.”[[4]](https://en.m.wikipedia.org/wiki/Rings_of_Saturn#cite_note-history_of_the_rings-4) He mused, “Has Saturn swallowed his children?” — referring to the myth of the [Titan](https://en.m.wikipedia.org/wiki/Titan_(mythology)) [Saturn](https://en.m.wikipedia.org/wiki/Cronus) devouring his offspring to forestall the prophecy of them overthrowing him.[[5]](https://en.m.wikipedia.org/wiki/Rings_of_Saturn#cite_note-Whitehouse2009-5)[[6]](https://en.m.wikipedia.org/wiki/Rings_of_Saturn#cite_note-Deiss2016-6) He was further confused when the rings again became visible in 1613.[[4]](https://en.m.wikipedia.org/wiki/Rings_of_Saturn#cite_note-history_of_the_rings-4) ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [October 12, 2022, 4:53am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/29 "2022-10-12T04:53:14Z")
> [@JohnGalt](#): > > Another thing you should try when camping is to find the Andromeda galaxy, easiest in the summer. After finding it with binoculars, try to see if you can see it without aid. Seeing another galaxy with your naked eyes, and recognizing it as a galaxy _that you can see_ is mind-blowing. Some years ago when I was living in Carson City at 5,000 feet with dark skies, one August night after studying a Messier chart I walked out with my 7x50s and star-hopped from Andromeda (the constellation) to M-31. Once I had done that it was a snap to repeat the process with my pair of Mk I eyeballs and I had the same sense of wonder. _I am seeing the most distant naked eye object there is._ ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [October 12, 2022, 4:59am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/30 "2022-10-12T04:59:05Z")
> [@crowmanyclouds](#): > > All Copernicus needed to think about in one pic, The thing Kepler came up with, with elliptical orbits and equal area orbital speed - was because while everyone agreed - eventually - that Copernicus had explained and simplified a lot, there were substantial numbers of “cosmos deniers” who pointed out “if the planets are moving in circles around the sun at constant speed, and so are we, they are not quite where we should be seeing them in the heavens”. Kepler determined that was because they neither moved in exact circles, nor at constant speed. Then Newton showed that gravitational forces could explain the motion Kepler came up with. It was always a work in progress. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [October 12, 2022, 5:47am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/31 "2022-10-12T05:47:58Z")
> [@md-2000](#): > > the planets are moving in circles around the sun I like that the common Person on the Street would give this as the correct answer despite the more correct answer being ‘ ~~The planets~~ Objects in the Solar system are moving in ~~circles~~ orbits around their barycenter with the Sun’. But at that point we’re in Asimov’s _The Relativity of Wrong_\* land. \*Geocentrism is making a comeback thanks to Flat Earthers and other stupid folks. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [October 12, 2022, 8:02am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/32 "2022-10-12T08:02:42Z")
> [@crowmanyclouds](#): > > ‘Objects in the Solar system are moving in orbits around their barycenter with the Sun’. I just heard/learned my, obvious, word of the day _barycentric_. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 12, 2022, 8:23am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/33 "2022-10-12T08:23:14Z")
> [@DesertDog](#): > > M-31. Once I had done that it was a snap to repeat the process with my pair of Mk I eyeballs and I had the same sense of wonder. _I am seeing the most distant naked eye object there is._ I hate to squelch anyone’s sense of wonder, but we are nitpickers here on the SDMB. I believe the furthest naked-eye object is M-33, the Triangulum Galaxy. It’s not very bright (apparent magnitude 5.72) because it’s smaller, but it is somewhat further than Andromeda (2.73 vs 2.5 million lightyears). You’d need a dark site to see it, but it sounds like that’s what you had in Carson City. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [October 12, 2022, 8:56am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/34 "2022-10-12T08:56:39Z")
Dammit! You’re a real hoot at parties, aren’t 'cha. At least it’s a short hop from -31. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [October 12, 2022, 11:25pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/35 "2022-10-12T23:25:07Z")
> [@dtilque](#): > > The geocentric/heliocentric debate was about the Solar System and ignored everything else. So I don’t think failing to account for Sgr A\* is a valid criticism. There was an admission they had no info on stars… But a very good explanation for the wanderers would explain (eg allow measuring the distance to them. ) stars too, and explain the galactic galaxy (I mean, the milky galaxy … the galactic way … “the milky way” galaxy means milky, you know ? all galaxies are therefore milky … but ok “the milky way” is our galaxy ) they hadn’t neglected that they wanted an explanation for stars. just they had no info so far. But Ok, they accepted the wanderers could be separate to stars and the milky way. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [October 13, 2022, 12:30am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/36 "2022-10-13T00:30:16Z")
> [@md-2000](#): > > > [@crowmanyclouds](#): > > > > All Copernicus needed to think about in one pic, That is not the real pic, though; here is the one from @MikeS 's link: [![](https://1.bp.blogspot.com/-_MUPCNejH0I/UhWIml-2L5I/AAAAAAAAAaU/MTS0EzyPxGY/s1600/Ptolemaic+and+Copernican.jpg) ](https://1.bp.blogspot.com/-_MUPCNejH0I/UhWIml-2L5I/AAAAAAAAAaU/MTS0EzyPxGY/s1600/Ptolemaic+and+Copernican.jpg) > [@](#): > > The thing Kepler came up with, with elliptical orbits and equal area orbital speed - was because while everyone agreed - eventually - that Copernicus had explained and simplified a lot, there were substantial numbers of “cosmos deniers” who pointed out “if the planets are moving in circles around the sun at constant speed, and so are we, they are not quite where we should be seeing them in the heavens”. Kepler determined that was because they neither moved in exact circles, nor at constant speed. Then Newton showed that gravitational forces could explain the motion Kepler came up with. It was always a work in progress. An ellipse is basically a circle + an epicycle, though, so the Copernican picture does not make the epicycles go away—the planets are seen not to be moving in circles at constant speed. Some people (i.e., Tycho Brahe) were able to make observations good enough to compute the planetary orbits (i.e., where we should be seeing them in the heavens) more accurately. I recall there was even a discussion on this board concerning Kepler’s geometric procedure for calculating the orbit of Mars (eccentricity 0.093) ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 13, 2022, 12:47am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/37 "2022-10-13T00:47:06Z")
> [@DPRK](#): > > Some people (i.e., Tycho Brahe) were able to make observations good enough to compute the planetary orbits (i.e., where we should be seeing them in the heavens) more accurately. And note that Brahe made up his own system, which was a compromise of Ptolemy and Copernicus. That is, the Sun and Moon went around the Earth and all the planets went around the Sun. It still had circular orbits, although he didn’t actually work out the math on his system, so it had no epicycles or deferents. [![](https://www.physics.unlv.edu/~jeffery/astro/tycho/tychonic_system.png) ](https://www.physics.unlv.edu/~jeffery/astro/tycho/tychonic_system.png) ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [October 13, 2022, 4:49am UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/38 "2022-10-13T04:49:47Z")
> [@dtilque](#): > > > [@Pleonast](#): > > > > I’m not sure if comets or meteors were classified as planets or not, but I believe not, as they are not permanent. > > At the time in question, it wasn’t even certain that comets were astronomical bodies. Some thought they were atmospheric phenomena. It wasn’t until Edmund Halley predicted the return of a comet which actually happened that they were confirmed to be astronomical. Tycho Brahe demonstrated that comets were at least as far away as the moon in 1577, by combining his observations with those of others and proving that comets showed no parallax. All Halley added was the demonstration that comets could be _periodic_ as well. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [October 13, 2022, 2:24pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/39 "2022-10-13T14:24:39Z")
> [@Andy\_L](#): > > Galileo could barely tell that there was something funny about the shape of Saturn - but modern binoculars can see the Rings pretty clearly, right? My modest 5" Celestron could see Saturn’s shadow on the rings, which was pretty cool. Galileo also missed noticing that Neptune was moving-discovering that planet 250 years before others did would have blown some more minds. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [October 13, 2022, 2:38pm UTC](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010/40 "2022-10-13T14:38:12Z")
Here’s a book about Medieval science that focuses almost exclusively on astronomical devices: [https://www.amazon.com/Light-Ages-Surprising-Medieval-Science/dp/0393868400/ref=tmm\_pap\_swatch\_0?\_encoding=UTF8&qid=1665671749&sr=1-1](https://www.amazon.com/Light-Ages-Surprising-Medieval-Science/dp/0393868400/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1665671749&sr=1-1) It’s too early for the OP era, but I figure you would find it interesting. [Previous page](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010.md?page=1) [Next page](https://boards.straightdope.com/t/what-observations-did-copernicus-make-that-argued-for-a-heliocentric-view-of-the-universe/973010.md?page=3)