Circles within Circles
The universe versus the heavens
Bryan Zepp Jamieson
March 20th 2025 Happy Equinox!
I just finished watching an anime series on Netflix called Orb. It’s 25 episodes, and is based on a highly fictionalized 14th and 15th century Europe, where a church, identified as “C” is fighting to preserve the biblical belief that Earth is the center of creation, and is the bedrock, immobile, and all other heavenly bodies rotate around it. A disparate group of sky watchers, some clergy and some not, dispute this view, arguing that the Earth actually goes around the sun. The church reacts with a vicious inquisition and with death by burning mandated for heliocentric heretics. It is basically a fictionalized account of the general tone of the 14th through 17th centuries.
I was going to do a review of the series upon its completion, but the fact of the matter is it isn’t very good. The characters are wooden and two dimensional, and while it shows charts showing the patent absurdity of the church’s beloved geocentric model, it doesn’t really explain why the far simpler and logical heliocentric model didn’t prevail. After all, it already did in such places as Japan, China, India, and the Middle East. (It was also known in parts of the Americas, but Europe didn’t know about the Americas at that point.) One of the rationales for the Crusades was that the ‘heathen Muslims’ believed the sun was the center of the universe.
It had its moments of absurdity, as in when one cleric found his faith in geocentrism shattered by finally observing Venus “in full phase.” Since Venus and Earth are on the same orbital plane, the only time Venus would be in full phase in relation to the Earth is when it is directly behind the sun from us. And finally, the ending of the series was nonsensical, abrupt, and confusing. Bit of a shame, really—it did start out promising, and at least some of the people involved did the homework. The casual background images of the sky, especially at night are amazing, accurate, and in a few sequences when the POV is over several minutes with stationary objects to the side, you can actually see rotational movement of the stars as they are occluded by the foreground object. That was impressive. As noted, someone put some real work into this.
I had recently encountered stats showing that a full 26% of American adults—over a quarter of the voting population—believe the sun goes around the Earth. A smaller but still statistically significant portion of the population believe the Earth is flat. I can’t even blame religion for this: America has a deep anti-intellectual, anti-science and unimaginative streak, one exemplified by the present administration. This is encouraged by industries that find scientific analysis of their products and emissions to be inconvenient and even expensive. Easier to dismiss science than it is to argue against it. I encounter victims of this on line, and sometimes I’ll actually engage with them. (As soon as religion or conspiracy theories show up, I just block them as a waste of carbon.) I like to challenge them to work out the math for a flight, using the Hohmann transfer trajectory, to get to Mars and back. I can do one good enough for nevermind, and I’ll bet there’s an app for my phone that could do it up to NASA or ESA requirements, too.
One of the more impressive elements of the series was the display of the movements of the planets. Astronomers of the era bent over backwards to display the elements of apparent planetary motion. The results usually look like they were done on a Spirograph. This is because the five inner planets as seen from Earth move backwards at regular intervals for varying amounts of time. It’s called retrograde motion, and it’s easily explained by the heliocentric model.
Think of it as a circular race course, with each planet in its own lane—Mercury on the innermost, Saturn on the outermost. Earth is in the center one. Mercury goes around every 88 days, Venus every 225 days, Earth every 365 days, Mars every 687 days, Jupiter every 4,333 days, and Saturn every 10,756 days. It makes for a very boring race, I agree.
In the middle track, Earth races ahead of the slower outer planets, passing them and making them appear to move backward compared to the fixed objects in the background—in this case, the stars. The two inner planets appear to move backward against the stars because when their orbits on are on the far side of the sun, they are. If we’re at 3 o’clock moving toward 2 o’clock (sorry but they move counterclockwise seen from above) then the two might be moving from 11 o’clock to 7 o’clock.
Heliocentrism explains that phenomenon without having to have a body stop dead in its tracks and then loop back on itself with grand disregard for inertia or common sense. Unfortunately, the religious fundamentalist mind tends to embrace the more convoluted and irrational explanation as evidence that God’s powers exist and are above the silly laws of the world.
Nonetheless, heliocentrism prevailed. Without math and scientific theory to support it, it was a competing opinion. But with math, it all adds up.
Let’s take a look at how that happened.
Per Wikipedia: “The first non-geocentric model of the universe was proposed by the Pythagorean philosopher Philolaus (d. 390 BC), who taught that at the center of the universe was a ‘central fire’, around which the Earth, Sun, Moon and planets revolved in uniform circular motion. This system postulated the existence of a counter-earth collinear with the Earth .”
The heliocentric model, while much simpler than any Earth-centric model, lacked anything beyond Occam’s Razor to justify it. Without math to describe it, it was just another opinion. Copernicus started that route, stating that the orbits were circular, with a motionless sun at the center, and unvarying. All three statements were incorrect, and had no more empirical justification than any other theory, but it was a step in the right direction.
Kepler, between 1609 and 1619, devised his three laws that clarified the behavior of the solar system.
Kepler’s three laws state that:
- The orbit of a planet is an ellipse with the Sun at one of the two foci.
- A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
- The square of a planet’s orbital period is proportional to the cube of the length of the semi-major axis of its orbit.
It wasn’t until Newton released his Principia in 1687 that he deduced the ratios of gravitational attraction.
He determined that the force of that attraction (F) was equivalent to the mass of the first object times the mass of the second object, divided by the distance between the centers of the two masses, squared.
Newton was flummoxed by his own discovery, writing “That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it.”
Absurd or not, it was the death knell of theological objections to the heliocentric theory of the solar system.
The final nail in the coffin came over a century later, when Henry Cavendish devised the universal gravitational constant, which described the strength of the gravitational attraction (6.674 × 10−11m3⋅kg−1⋅s−2) which showed exactly why the planets moved the way they do.
With that, the last piece fell into place and heliocentrism was established theory, on par with evolution, gravity, and atomic theory. We have landed craft on Mars and Venus, and approached all the other planets, using the advances listed above to do so. You fling a craft at Mars, and you aim it while it’s still within a few thousand miles of Earth and it COASTS to its target, some 130 million miles away. Moving target. That’s one hell of a game of darts!
With fascists and religious fanatics clawing down every scientific and philosophical advance since the 14th century, it’s important that you stand for science and knowledge. But you need to know WHY you are standing for it, and have the tools you need to defend it, and the knowledge to explain it. You aren’t like those morons who take it on faith because god loves irrationality, or it’s a commie plot.
A lot of science is well beyond the ken of any normal person. Quantum physics, with indeterminacy, eigenstates and probability collapses, is confounding, especially since we live in an artificially stable world above a foundation of chaos and random chance. We don’t really know if the universe is expanding, contracting, or not doing anything at all. Or if it has edges. The cosmological constant provides us with the unsettling news that the density of the universe just happens, by chance, to exactly match the amount of dark energy (which seems to be decreasing) and without the match, we wouldn’t exist at all.
Fortunately, you don’t have to take any of that on faith. It reflects nothing but the current state of our knowledge, and we really are still seven blind men trying to describe an elephant. Upheavals in our apprehension of the universe are frequent. The wonder and strangeness of the universe will always far exceed our imaginations.
But in our quotidian lives, some things are infallible and constant. Among them: the Earth is an orb, and revolves around the Sun. The Sun revolves around the Milky Way core. In fact, it’s safe to say that in our universe, everything revolves around something else. With one possible but as yet unknown exception.
Don’t hesitate to slap down the flat Earthers. But do take the effort to understand WHY you are right and they are wrong. You owe that, not just to them, but to yourself.
