# Prove that the Earth orbits the sun **URL:** \ **Category:** Great Debates\ **Created:** [February 20, 2014, 3:49pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795 "2014-02-20T15:49:44Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [February 20, 2014, 10:43pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/41 "2014-02-20T22:43:30Z")
:rolleyes: Why do I bother? > [@XT](#): > > It’s probably already been used, but [here](http://curious.astro.cornell.edu/question.php?number=190) is a link: I have already pointed out how this is unsuitable to convince a skeptical but open-minded layperson, such as we may take the letter writer in the OP to be. (Basically, they will not be able to able to understand how any of the evidence that they can be shown, which will be such things as tables of figures, bears on the point at issue: not, that is, without taking a great deal - about the workings of complex equipment and details of elaborate mathematical analyses - on faith.) However, I have also pointed out that observations of the phases of Venus, which they could easily make for themselves, would sufficiently prove the point, and could be readily understood (given suitable diagrams) by any reasonably intelligent person. This may not be direct evidence for the movement of the Earth, but the observable phases of Venus can only be reasonably explained (in the context of present-day common sense) on the hypothesis that the Earth orbits the Sun. > [@Learjeff](#): > > With the telescope, Galileo showed these facts that disagreed with expectations: > > 1. Jupiter’s moons: this was the first clear evidence of anything orbiting something other than Earth > 2. phases of Venus, as mentioned above. More below > 3. the moon has craters (it was assumed to be perfectly spherical, as part of the perfect heavens) > 4. the milky way was mostly stars, not nebulous clouds Only the second of these is directly relevant. The other observations served to weaken the appeal of aspects of the Aristotelian theory of the universe, but they say nothing about the Earth’s motion as such. > [@Learjeff](#): > > Regarding Venus, it could have phases and still conform to Ptolemy’s model of concentric heavenly spheres. If Venus’s sphere was outside the Sun’s, it would only show full and gibbous phases. If it was inside the Sun’s, it would show only crescent and new phases. Galileo showed that it had all phases, shattering the Ptolemaic model completely, and causing astronomers to adopt hybrid theories that allowed both Earth and the Sun to be the centers of revolutions – oddly, ignoring his earlier demonstration of Jupiter’s moons. Venus _would_ show phases on Ptolemy’s model, just not the same phases as are observed (which are certainly not _all_ phases: some are unobservable from Earth as Venus would only display them during daytime.) Also, it had been clearly understood since ancient times that Venus orbits between the Earth and the Sun. The notion that “Venus’s sphere was outside the Sun’s” was never a live possibility. > [@jtur88](#): > > Can’t, because it not a reproducible experiment. But observational evidence is strong enough to feel safe using it as an assumption, and so far nothing has failed to work when attempted with the assumption that the earth orbits around the sun. Reproducible observational evidence is just as good as experimental evidence for scientific purposes. If this were not so, sciences such as astronomy, geology, paleontology, and most of evolutionary biology would not be “real” sciences (which, of course, they are). ---
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [February 20, 2014, 10:54pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/42 "2014-02-20T22:54:37Z")
> [@Great\_Antibob](#): > > The flaw in the letter is a false equivalence between faith in something ineffable and faith in something we simply choose not (for lack of resources or desire) to personally verify. > [@garygnu](#): > > Accepting a fact that can be readily observed, even if you haven’t done so yourself, isn’t faith. Actually, personal observation is a pretty unreliable way to nail down the truth of existence. > [@CurtC](#): > > I accept that France exists, although I’ve never verified it myself. My acceptance isn’t called “faith.” I have confidence that if I went to the trouble, I could visit France myself, just like I could take the trouble to make the same astronomical observations that people have been doing for hundreds of years to see for themselves that our solar system is heliocentric. My take on it: the wrong word is being used. What is addressed here is not “faith”, it’s “_ **trust** _”. I don’t “have faith in” a scientific theory, I _trust_ a scientific theory (and not just any one or all, since some of them have shown themselves more trustworthy than others). ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [February 20, 2014, 11:11pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/43 "2014-02-20T23:11:03Z")
> [@JRDelirious](#): > > My take on it: the wrong word is being used. What is addressed here is not “faith”, it’s “_ **trust** _”. I don’t “have faith in” a scientific theory, I _trust_ a scientific theory (and not just any one or all, since some of them have shown themselves more trustworthy than others). Exacly. There’s a massive amount of peripheral evidence that France exists, and the evidence we see is consistent - outrageous accents, funny bread and stinky cheese, bizzarre fashions… There’s a simple experiment to prove it exists that involves [Expedia.com](http://Expedia.com) and a credit card. Of course, if you maintain the whole city of Paris is a giant Potemkin village built expressly for your benefit along the Mississippi, I’m not sure how I can convince you- ithat becomes a variation on the true scotsman meme, everything is “simply not true” if it contradicts your random assertion. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [February 21, 2014, 4:35am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/44 "2014-02-21T04:35:11Z")
> [@JRDelirious](#): > > My take on it: the wrong word is being used. What is addressed here is not “faith”, it’s “_ **trust** _”. I don’t “have faith in” a scientific theory, I _trust_ a scientific theory (and not just any one or all, since some of them have shown themselves more trustworthy than others). But that’s the thing - “faith” does mean “trust.” But, in another definition, it means belief that doesn’t rely on evidence. You frequently hear religious people equivocating between the two. So every time they do it, we have to take the trouble to explain that it’s really as if they’re two different words, just spelled and pronounced the same. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [February 21, 2014, 5:06am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/45 "2014-02-21T05:06:14Z")
My usual point is that religious faith embodies “revealed truth”. That is a truth that is taken as axiomatic and is revealed as part of the faith (usually in a large floppy book.) Scientific results aren’t revealed truths. But the OP’s question is set by a person who is equating the “truths”. In the sense that many such scientific results are provided in books, there is a certain commonality, but the point about the steakhouse or France is exactly right - there is a level of trust you place in the book that is not absolute, and varies along a scale of credulity. I do put more trust in a book on astronomy than a travel guide. Recommendations about steakhouses are especially untrustworthy. But if I was in Perth and there was a need to find a steak, I would probably trust the guide enough to give the place a go. Once I had done so, I would consider that I had more trustworthy information than the guidebook. I don’t get that option with revealed truths, if my experience doesn’t match the book, it is me who is wrong, by definition. ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [February 21, 2014, 5:32am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/46 "2014-02-21T05:32:22Z")
Is this not the real reason Galileo got into trouble? That he lampooned the Pope for being an idiot to believe a theory was at the time the best known scientific position, while his own had no definate proof. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [February 21, 2014, 5:59am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/47 "2014-02-21T05:59:53Z")
> [@DrCube](#): > > Faith is believing something without reason. I have to take objection to this line of argument. Pet hate: it is one that really annoys me. And I know that there are a lot of Christians espousing a kind of blind faith that excludes any kind of rationality. I cannot speak for other religions, but I know that the concept of faith is a well established and well defined concept within the Bible. And nowhere does it imply that faith is at the expense of rational judgement. Faith is an expression of trust precisely because there is good evidence to suggest that the object of the faith is trustworthy. [William Lane Craig](http://www.youtube.com/watch?v=bPwW304RgDk) says it as well as anyone. Not getting at you **DrCube** or anyone else for that matter. I am just tired of witnessing good discussions that get hijacked by this persistent notion that Christianity and belief in God is somehow a death sentence to logical deduction from evidence to conclusion. And I get frustrated with the number of Christians who glibly accept this characterisation and even advance it. The Bible uses faith in more or less the same way that we use it in everyday speech about things and people that we trust. It most certainly is not a blind leap into irrationality at the expense of reason. Back on topic > [@shiftless](#): > > The OP’s question supposes only two possible ways of explaining a phenomenon: 1) Either the explanation for the phenomenon can be easily demonstrated to any layman or 2) we have to blindly accept any explanation that is presented, no matter the source. I think there is some middle ground there. > > I can’t prove to any and all that the earth orbits the sun but I have studied physics and math and I’ve looked up at the sky, so I can see that some statements about the way the sun and the Earth interact are much more informed than others and, over time, I’ve come to accept those authorities over guys like the OP’s letter writer. More importantly, if I am moved to get off my lazy ass, I can learn about others who have challenged the ideas that I ‘believe’ and I can see the arguments and the outcomes. > > Anyway, there are lots of ways of demonstrating that the Earth orbits the sun, depending on what one means by that. You can learn all about it in college. The fact that they aren’t all simple concepts that are clear to every person on the planet has no relation to their truth or usefulness as a model. Easily the best comment on the topic. There are differing degrees of proof with different levels of appeal to the work of others, authorities and appeals to models of varying complexity. It really depends what level of proof is required to convince you. Phases of Venus with an accompanying geometrical diagram explaining the observations would do it for me – and I wouldn’t feel a personal necessity to come up with the diagrams or make the observations myself. If someone gave them to me, that would probably suffice. (My patience with telescopes is pretty slim.) Which all addresses the bigger question of how we know what is true. And if I read it right, it was this discussion that prompted the original question. I think it is pretty common for people to apply different standards in different contexts and to not always be entirely consistent. What I do know is that the truth-claims of the Bible withstand a lot closer scrutiny than people generally assume. Comments like **Cheesesteak** ’s are generally unhelpful. Bible textual criticism involves a lot more rigorous scholarship than he implies. > [@Cheesesteak](#): > > The guy having faith in an afterlife does not have anything like this. He has a book written by basically anonymous people thousands of years ago, edited and re-translated who knows how many times, with no actual ability to go to the source of the knowledge. There is no independent verification of the claims, it must be taken entirely on faith. Regarding the geometry of the solar system we can say definitely that it is possible to deduce from relatively simple observations a reasonably accurate model of the motion of the earth with respect to the sun. That after all was how it was discovered historically. The reality is that most people would not feel a compulsion to check this out for themselves and will readily accept the word of an authority on the matter. The letter-writer’s hypothesis stated by **DrumGod** in post one stands IMO. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [February 21, 2014, 6:04am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/48 "2014-02-21T06:04:34Z")
> [@Drum\_God](#): > > The letter-writer’s hypothesis is that we all live by faith. He knows that the Earth orbits the sun, but since he cannot observe this phenomenon directly, he takes it on faith. “Galileo said it. I believe it. That settles it.” ---
**Author:** ![appleciders](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@appleciders](https://boards.straightdope.com/u/appleciders)\ **Post date:** [February 21, 2014, 6:53am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/49 "2014-02-21T06:53:51Z")
> [@Chronos](#): > > Honestly, I’ve never seen that the moons of Jupiter were all that big of a deal. How do we know that the Galilean moons orbit Jupiter? Because they always stay close to it in the sky. But we already have an example of that, differing only in degree, with Mercury and Venus staying close to the Sun. If you’re going to come up with some contrived mechanism to keep Mercury and Venus close to the Sun without actually orbiting it, then you could use the same mechanism to keep Io, Europa, Ganymede, and Callisto close to Jupiter without orbiting it. The difference is that you can watch Io make a big chunk of its orbit in a single night. I’ve done it. It doesn’t take long periods of careful calculation and measurement; you just point the telescope at Jupiter and watch Io move from well away from Jupiter to being eclipsed by it. It’s a gut-level impact; while this is not in scientific principle any different, it’s important emotionally because your eyes are telling you very explicitly what’s going on, that Io is orbiting Jupiter. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [February 21, 2014, 7:11am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/50 "2014-02-21T07:11:53Z")
> [@j\_sum1](#): > > The reality is that most people would not feel a compulsion to check this out for themselves and will readily accept the word of an authority on the matter. The letter-writer’s hypothesis stated by **DrumGod** in post one stands IMO. Trouble is, there is no mechanism for anyone, either the reader or anyone who claims some authority, to check out the revealed truth, so acceptance of the word of “an authority” comes in a critically different form. Accepting the word of a scientist is a accepting the idea from someone who does preport to have checked something out, and who, as a proxy for the reader (as another human being), has done the legwork, and performed an act that the reader, could in principle, have carried out themselves. Accepting the word as written in a religious text as the word of God is not the same. No matter how lazy or active the reader is, they have no mechanism to check out the existence of the afterlife, nor do the words in the book convey information from any such human proxy who has done so. The nature of “an authority” is different in a basic sense. There is a weak equivalence, in that the lazy can be equally credulous of anything they read, if they choose, or don’t care. The plethora of conspiracy theories, and new agers, anti-vaxers etc, rather bears out that many are indeed so lazy. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [February 21, 2014, 7:38am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/51 "2014-02-21T07:38:23Z")
Sorry **Francis** if I was unclear on that point. The writer of the letter claims that everyone accepts things on faith. Given that the word faith is bandied around with an assortment of meanings, I have attempted to clarify. It seems also that it is possible to deduce the earth’s orbit from observation in quite a straightforward fashion which is contrary to what the writer was saying. However, his central point as posited by DrumGod was that everyone accepts stuff on faith and I would say that that particular point is unchallenged. As for a line of reasoning to defend the Bible - I am not going to hijack this thread especially this close to home time. Suffice to say that there is strong archaeological support, very strong manuscript support and theses within the Bible that can be tested experientially. Which is to say that the Bible contains some truth. Of course the Bible’s claim is to be _The Truth_ which raises the stakes somewhat. There are several lines of reasoning that one can take that would tend to support a supernatural origin of the Bible. That is not a point to be surrendered lightly, but seems to be an obvious and expected characteristic if it is produced by a supernatural God. Once that point is conceded then it is possible to admit the supernatural claims of the Bible’s message: miracles and the like. Having now established that it contains truth and a plausible (or at least internally consistent) claim to supernaturality, the next step is a study of the Bible’s claims about creation, the nature of humans and the character of God and a systematic comparison of these with what can be observed. If the results of this comparison are favourable, it is but a small step to stating equivocally that the Bible is The Truth: a step comparable with the conclusive statements that scientists make all of the time regarding their own hypotheses. It is not my intention to hijack this discussion and I fear that I already have. This properly belongs in GD and it is vital that the debate proceeds properly with due respect for the evidence and the reasoning process. My essential point in the context of this thread is that under the banner of _faith_ rational discussion is often abandoned and there are Christians who are happy to have it that way. Pisses me off. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [February 21, 2014, 7:51am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/52 "2014-02-21T07:51:24Z")
> [@md2000](#): > > The thing is, you could argue a ptolomeic system - some planets orbit the sun, which then orbits the earth. That, however, relied on magical powers (or perhaps, unknown unspecified forces) that allowed an extremely large mass to circle a smaller one. > > Newton’s theory, which can be proven at multiple scales depending on your wallet, demonstrates a simpler model - gravity works the same on all masses, and results in planets circling the sun, moons orbiting planets, and apples falling - all obeying the same law. > > Things like star parallax or doppler shift of spectral lines in distant stars are simply gravy that reinforce the vast pramid of established knowledge. But if you feel any particular piece of that pyramid of science knowledge is flawed, you can devise an experiment to check it. If you feel the theory of gravity is incorrect - in which way? “Everything in gravity works except sun orbits earth”? What happens as solar wind particles and meteorites fall onto the earth? Do they magically become “earth” and violate the laws of gravity? or has earth statred to move oh so slightly in recent eons due to the influx of non-earth material? …and so on. As [this](https://blogs.discovermagazine.com/badastronomy/2010/09/14/geocentrism-seriously/) article says, you can certainly model everything in the universe (including things like the coriolis effect) from a stationary geocentric perspective, but it’s a horrid, horrid, janky, unholy mess and the math would be such a pain in the ass to do nobody would actually dare try it. Of course, the bigger caveat is that I can pick any arbitrary frame in the middle of nowhere. and model the universe around THAT point instead. Thus, everything revolves around my left nostril. It depends what’s easiest for whatever you’re calculating. It’s not that a geocentric system is **wrong** , since the math works out you will certainly come up with self-consistent rules for how forces act on each other. The question becomes “how can I show the earth orbits the sun” and moves towards “how can I show that modelling the sun orbiting the earth is a bad idea if you ever want to get anything done?” You can claim Occam’s Razor and say the simpler math is therefore “correct”, but I don’t think that’s a valid invocation of Occam’s Razor. The point of reference for a celestial body’s orbit is a matter of convenience, not truth. Both are equally, identically correct. Occam’s Razor only really applies in differentiable scenarios. In this case, both scenarios can be losslessly be transformed into one another mathematically, albeit with a ton of work. The same is not true when, e.g., insisting that leprechauns keep stealing your socks. Picking the sun is no more “right” than saying “x=y” is “more correct” than “x+2=y+2”, IMO. In fact, computer graphics abuses this property as a matter of course. Every frame, the world is modelled as a hierarchy – first each object is transformed relative to some arbitrary center point within itself, and then it’s transformed relative to some “camera”\*. “The camera moving forward” is mathematically modelled as everything else being transformed backwards, rotation is modelled as everything else rotating you, and so on. You DO use scenegraphs to introduce intermediate transformations (we may model the earth rotating around its center, and then around the sun, and then the sun around some galactic centroid like we do in real life), but in the end, the aggregate of these transformations semantically means “move this vector in this way around the unmoving, unrotating point I designate (0,0)”. In the end, everything in the range [-1.0,1.0] for both x and y shows up on screen. It works well, and is clearly correct if you’ve ever played a 3D game or watched a 3D movie, it’s just not intuitive to work in such a coordinate system, hence why we multiply a bunch of matrices to get it rather than model the weird camera-centric nonsense by hand. \*There’s usually a third step too, called the perspective transformation, but it’s not horribly relevant to this discussion. It warps everything so that the closer something is to the camera, the less it deviates from the center in the x and y directions. That’s mostly to ensure that the same transformations occur regardless of screen width and height. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [February 21, 2014, 7:58am UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/53 "2014-02-21T07:58:26Z")
> [@Jragon](#): > > Every frame, the world is modelled as a hierarchy – I want to be clear that this is a frame in the graphics sense, not the physics sense. ---
**Author:** ![JKellyMap](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jkellymap/32/15880_2.png) [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)\ **Post date:** [February 21, 2014, 12:36pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/54 "2014-02-21T12:36:55Z")
> [@AK84](#): > > Is this not the real reason Galileo got into trouble? That he lampooned the Pope for being an idiot to believe a theory was at the time the best known scientific position, while his own had no definate proof. It wasn’t the “best known scientific position,” because even before Galileo it was relying on multiple gross violations of Occam’s Razor. It was the “best known way to force a preconceived axiom on the data, pointlessly ignoring a much simpler explanation.” ---
**Author:** ![JKellyMap](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jkellymap/32/15880_2.png) [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)\ **Post date:** [February 21, 2014, 12:55pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/55 "2014-02-21T12:55:56Z")
ETA: I just read jragon’s long post. I think it’s well written and interesting, but I disagree about Occam’s Razor. Sure, the mathematical description of a system might not care if the “Sun revolves around the Earth” or vice-versa, but there is a higher-level understanding the human brain perceives (or, as you might prefer, “imposes”) on the universe around it. Your computer graphics analogy is a fascinating one, but to me it just reinforces the point, because it reminds us that, even “below” the math functions you mentioned, there is compiled code, and machine code, and ultimately just on-off switches (sorry I’m bad at describing this). Occam’s Razor WOULD apply to computer motion graphics, at the moment you introduced the idea “Which interpretation of the math best fits how humans perceive movement?” – that is, “given the PURPOSE of this human-designed creation, what is the simplest explanation for why the equations are what they are? What is the most likely thing this creation is trying to mimic?” So, getting back to stars and planets, the higher-level concept of “simpler explanation” as it pertains to our human brains’ need to (and generally excellent ability to) generalize and affix labels to these generalities DOES make Occam’s Razor relevant, IMHO. True, the brain’s generalizing capacity sometimes gets us into trouble, but in this case I see no reason to pretend that “Earth revolves around the Sun” is anything but a TRUER statement than its opposite, in 999 out of a thousand contexts. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [February 21, 2014, 1:21pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/56 "2014-02-21T13:21:54Z")
> [@Jragon](#): > > As [this](https://blogs.discovermagazine.com/badastronomy/2010/09/14/geocentrism-seriously/) article says, you can certainly model everything in the universe (including things like the coriolis effect) from a stationary geocentric perspective, but it’s a horrid, horrid, janky, unholy mess and the math would be such a pain in the ass to do nobody would actually dare try it. Of course, the bigger caveat is that I can pick any arbitrary frame in the middle of nowhere. and model the universe around THAT point instead. Thus, everything revolves around my left nostril. > > It depends what’s easiest for whatever you’re calculating. > > It’s not that a geocentric system is **wrong** , since the math works out you will certainly come up with self-consistent rules for how forces act on each other. > > The question becomes “how can I show the earth orbits the sun” and moves towards “how can I show that modelling the sun orbiting the earth is a bad idea if you ever want to get anything done?” You can claim Occam’s Razor and say the simpler math is therefore “correct”, but I don’t think that’s a valid invocation of Occam’s Razor. The point of reference for a celestial body’s orbit is a matter of convenience, not truth. Both are equally, identically correct. Occam’s Razor only really applies in differentiable scenarios. In this case, both scenarios can be losslessly be transformed into one another mathematically, albeit with a ton of work. The same is not true when, e.g., insisting that leprechauns keep stealing your socks. Picking the sun is no more “right” than saying “x=y” is “more correct” than “x+2=y+2”, IMO. > > In fact, computer graphics abuses this property as a matter of course. Every frame, the world is modelled as a hierarchy – first each object is transformed relative to some arbitrary center point within itself, and then it’s transformed relative to some “camera”\*. “The camera moving forward” is mathematically modelled as everything else being transformed backwards, rotation is modelled as everything else rotating you, and so on. You DO use scenegraphs to introduce intermediate transformations (we may model the earth rotating around its center, and then around the sun, and then the sun around some galactic centroid like we do in real life), but in the end, the aggregate of these transformations semantically means “move this vector in this way around the unmoving, unrotating point I designate (0,0)”. In the end, everything in the range [-1.0,1.0] for both x and y shows up on screen. It works well, and is clearly correct if you’ve ever played a 3D game or watched a 3D movie, it’s just not intuitive to work in such a coordinate system, hence why we multiply a bunch of matrices to get it rather than model the weird camera-centric nonsense by hand. > > \*There’s usually a third step too, called the perspective transformation, but it’s not horribly relevant to this discussion. It warps everything so that the closer something is to the camera, the less it deviates from the center in the x and y directions. That’s mostly to ensure that the same transformations occur regardless of screen width and height. The point is that yes, you can establish any relative frame of reference as “fixed”. The whole point of the experiments done from Galileo to Newton and onward, combined with the math done by Newton and Kepler etc. - these experiments _explain_ why the suggested “earth goes around the sun” happens - gravity, a simple elegant explanation for everyday phenomena and astronomical activity too. That;s the key - there’s a simple model that (a) fits the explanation and (b) is based on simple experiments that you yourself can do, especially if you have two different sized cannonballs and access to the leaning tower of Pisa. Science is about creating models that fit data and allow experiments that can verify that behaviour. Religion, OTOH, is about blind faith. Someone, somewhere, sometime, said something. There is no way to verify it. _There are no experiments_. If you blow yourself up, we cannot verify you are in paradise or that you have the requisite 72 heavenly virgins supplied. If you throw yourself off a cliff, cherubim may or may not stop you from going splat… (Experience says they won’t). ---
**Author:** ![UncleFred](https://avatars.discourse-cdn.com/v4/letter/u/f0a364/32.png) [@UncleFred](https://boards.straightdope.com/u/UncleFred)\ **Post date:** [February 21, 2014, 1:26pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/57 "2014-02-21T13:26:08Z")
> [@Doughbag](#): > > I have faith in the believe, that the light in the fridge turns off when I close the door. > > … and the only way to be 100% sure that the light in the fridge is actually turning off, is by checking that it’s off… > > Ever sat in a fridge and really, really, really checked? > > Faith, right! So, God must be real as well and exciest – it’s the same, right? Drill a peep-hole in the side and watch what happens or… Leave a videocamera/smartphone inside or… go wild - put an ammeter in series with the bulb or… unless you want to drag Heisenberg or those guys into it and argue that the very nature of observing changes the result. ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [February 21, 2014, 2:55pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/58 "2014-02-21T14:55:04Z")
\*\*njtt \*\*has it correct. Here is a 1 minute (plus 29 second) video which explains why the phases of Venus are decisive evidence for a heliocentric model. In the geocentric model, Venus is always between the Earth and the Sun, moving on its epicycle. Consequently, the phases of Venus do not change substantially since Venus always has its sunlit face away from the Earth. Nor does the apparent size of Venus change much. However in the heliocentric model, Venus is sometimes between the Earth and the Sun and sometimes on the farside. The phases can be seen and the size changes. When Venus is between the Earth and the Sun, we would not see much of it because most of the bright side is pointed back to the sun. Venus would also seem larger because it’s closer. When it’s on the far side, we would see the fully illuminated face and it would appear smaller. This matched up with observational data. > [@njtt](#): > > Well, I say it only takes simple diagrams, but after ten minutes of Googling I am unable to find a version of the diagrams that do not either contain glaring errors (like not showing the Earth at the center of the geocentric model!) or simply fail to make all the relevant issues clear. Maybe like [this one](http://wisp.physics.wisc.edu/astro104/lecture5/F04_15.jpg)? > [@bup](#): > > Nevertheless, I think the guy made a good point. Many, many scientific facts we take on faith. I’ve become resigned to it. This is simply wrong and a gross misunderstanding of the scientific principle which takes nothing on faith. It is not necessary for each and every one of us to prove all scientific facts ourselves. That is meaningless and wasteful. However, many of the advances in science occur when a trusted fact winds up conflicting with a theory and then people must rethink or re-observe. > [@DrCube](#): > > I think we ought to stop calling trust “faith”. Faith is believing something without reason. Trust is having good reasons to believe something without it actually being demonstrated to you. Yes. This is the false equivalency which the letter-writer is attempting to me. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [February 21, 2014, 3:21pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/59 "2014-02-21T15:21:42Z")
The above statement by **TokyoBayer** assumes Newton’s law of gravity is true in all places and at all times in the classical universe. As such, he is completely correct although I think it’s fair to only say that it is very strong evidence. If the OP allows for a large enough telescope, then we can observe [the parallax](http://en.wikipedia.org/wiki/Parallax) of nearby stars. This would give us a second, relatively independent piece of very strong evidence. The question remains as to what the burden of proof is. Do two independent pieces of strong evidence qualify, or do we need three or more? Faith in something that can _never_ be demonstrated is dogma. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 21, 2014, 3:40pm UTC](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795/60 "2014-02-21T15:40:09Z")
> [@j\_sum1](#): > > Bible textual criticism involves a lot more rigorous scholarship than he implies. What does textual criticism tell you about the reality of the afterlife, or the divinity of Jesus? [Previous page](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795.md?page=2) [Next page](https://boards.straightdope.com/t/prove-that-the-earth-orbits-the-sun/681795.md?page=4)