Does this name sounds familiar to you? Unless you know someone named Hamanen, he is an ancient astronomer of one alien civilization I have created for a story...
In this post we will have a brief introduction to Alien Astronomy, how can a sentient species interpret it's world and how many hints are given by nature that the universe expands far far away above the clouds beyond the sky, to the distant stars...
We have one sun and one moon, both are roughly the same size in the sky, we decided one Earth's rotation is a day, and one revolution around the Sun is a year, the Moon orbits Earth every ~30 days at an average distance of 84 thousand kilometers, Earth orbits the sun at a distance of 150 million kilometers and it is the third of a planetary system of 8 planets, this major system we call the Solar System, but how did we get there?
You may know from science and history classes that we long ago found Earth was round and measured it's size, and the distance to the Moon and tried to find the distance to the Sun but it was up to the invention of telescopes that astronomy got far away in figuring out the solar system... Then, roughly forty years after the airplane invention we got to space and two decades later went to the Moon, our civilization skyrocketed after physics and astronomy became a strong field.
And yet, is fun to look at how other civilizations before globalism figured out the heavens above...
One major thingy I wouldn't like to mention but is a great example of both clever and ignorant thoughts, is the Flat Earth society, yes, it happens that after all, their arguments aren't all that stupid to hear, once you put yourself in their eyes for cosmology .
Reasons a civilization can be lead to believe their world is flat...
1. Their world is dense.
By being dense, I mean, their major population lives in one place, like the Mesopotamian region, everyone's people and major empires sharing the same 1000x1000km region, sharing the same alike ideas and religion, this creates the illusion the world is small and sum up with items 2 and 3.
2. Settled / Landlocked / Non-Traveler Civilization.
If their world is dense, then they have no real reason to travel far away from merch or even war, they will have a fixed view of the cosmos around them.
Explorers from Europe, ancient Greece and Egypt later found out that the constellations change the further south you go, what could only be explained if you were on one different hemisphere of a round Earth.
3. Lack of celestial hints.
If your planet is the first of the system, that is a lack of celestial hints, if it doesn't have a moon to drag their attention to the sky and host eclipses, that is a lack of celestial hint, if their system hosts few or dim planets in the sky, that is a lack of celestial hint, if the planets in the sky take too long to complete an orbit it is a lack of celestial hint. The opposite of those items is a good celestial hint and allow the study of celestial mechanics and stuff.
Now, imagine you live in the middle east, every great empire does exist a few hundred miles next to you, your people haven't traveled much, and if you read the post about Double Parent Systems, you may have noticed that when you live near the poles, the sky basically rotates around you from east to west along the horizon, the sun and the moon do basically circle around above the visible world, see any resemblance to the flat Earth model? The "observational model" is only barely matching with the northern hemisphere view of the world.
Of course, when we have the other facts in hand like the stars or the different movements of the sun and moon around the world, is pretty much easier to figure out whats happening out there... And I like to think about the Hoku because they had all those hints...
The Hoku
The Hoku civilization lives in the second planet of a small binary star system with five planets, the second planet has large moon with a ring system and an atmosphere, the inner planet is a Venus analogue, the outer planet is frozen Mars which is very bright at night, outwards a warm ice giant slightly larger than Neptune with a ring system and three Mars-sized moons, and then a large Saturn sized gas giant with no moons.
The binary star system is composed by a class-G yellow dwarf 0,88Msol with little more than half the sun luminosity, and a M-class red dwarf that contributes basically nothing in lighting, they orbit each other every 21 days, and appear separated by 11º in Hokushoku's sky (shoku = world, Hokushoku = world of the Hoku).
Yuhora, their moon, appear 7x larger in the sky than our moon being closer at a distance of 94.000km, it orbits the planet every exactly 2 local days. The moon's axis is tilted 172º in a way that it appears to be rolling sideways for and observer at the poles, it's ring system appears 11,5º wide in the sky and it follows the moon's equator, appearing to be upright when observed near the poles, and aligned with the horizon at the equator, the moon's orbital tilt of 20º never allow it to be fully new, or fully lit by the sun given that perspective let always a bit of its nightshade appear when full and a slit of day-side when new.
This way, any Hoku could hold a sphere, mainly a typical northern fruit that is almost perfectly round and compare the moon's illumination with the illumination of the fruit, and to be honest, it is so common that no one gave it much attention for centuries, until an astronomer named Hamanen Kalinen figured out that since the fruit is clearly being lit by the sun (named Paza, the Greater Sister, Unenja the red-dwarf is called the Little Sister), then Yuhora the moon might be being lit by the Paza as well, and alike the fruit, Yuhora is round...
(You can do this experiment yourself when the Moon and the Sun are both in the sky).
"Look how both the fruit and Yuhora are lit sir..."
Another thought
he had about the fruit and Yuhora was when studying light and
reflections made with a recent invention of the east, glass mirrors. He
noted that light-rays come in straight lines, nothing much of new,
engineers used shadows to calculate heights of buildings because it
travels in straight lines, but, that created parallel shadows of sticks
used in wall building during the day, but when the wall were lit by
torches and lamps, the shadows did converge towards the lamp, by
sticking white-painted fruits on the sticks during the day, the fruits
shadow on the wall were parallel, and when lit by a lamp, did converge
towards the lamp.
Eladimira Koreli's first notes about the Kalinean System, with measured distances.
Left is Hokushoku and it's moon, to the right is Paza and a statement above "it may be larger", hence traced line.
At the top, Kalinen's idea about light-rays and spheres, and at the bottom, the minimum measurable distance from Paza to Hokushoku to approximate scale.
Since Yuhora and a ball placed on the same direction were lit the same way like the fruits on the wall lit by Paza, rather than when lit by a lamp, regardless of time of the day, then he noted that Paza's size must be at least as wide as Yuhora's orbit around Hokushoku or larger, unfortunately were too occupied making math for the army and city building to make any serious measurements about Yuhora's distance to begin with, he used his military campaign travels to rough measure Hokushoku's size but only that, he was also responsible for timing the speed of sound, discovery of Germanium and Gallium, and inventing the Astronomical Time (1.2 seconds timescale), his ideas persisted to be tested centuries later...
- M.O. Valent, 12/07/2019
