Here are some more
Overheaven flags, this time for Europa, Callisto and Ganymede. Still working on a flag for Io, sadly I do not have flags for all of the Galilean moons. And I haven’t even started on the flags of the other 75 moons of Jupiter.
Yet.
First, we have the flag of Callisto. Like with the flag of Venus I shared earlier, Callisto’s flag at least in part symbolizes Callisto’s history of terraforming, though like all things on Callisto, it’s complicated.
White represents the pre-terraforming state of Callisto as an icy world (they didn’t want to go with some ugly shade of gray, alright?). Warming up Callisto led to the release of a small ocean’s worth of iron-tainted saltwater, akin to Antarctica’s real-life “Blood Falls”. The cratered glaciers of Callisto melted and bled away as the blood-water spilled out, during a period remembered as the “Hemorrhage”, which formed the iconic “blood lakes” of Callisto in the uncountable craters that cover the Jovian moon’s surface. So that's what the red is for. And green symbolizes the post-Hemorrhage biotic stage of terraforming, which of course wasn’t normal, because it turned out the blood-water was filled with mutagenic alien bacteria. This created a conundrum for the colonial project, due to the protocol that alien ecosystems be preserved however possible. A compromise was reached via splicing the alien bacteria with terrestrial plants (later animals, and eventually some of the people - a complicated story unto itself, of course). Today, temperate/semiarid Callisto is a foggy, misty moon of countless red lakes, a continuously-mutating ecosystem, and distinctive red-green flora. And that throws more symbolism onto the flag, which can also be interpreted as symbolizing an extraterrestrial biosphere meeting and merging with a terrestrial one. Even the white triangles are said to have relevant symbolism; they’re the craters, ridges, mountain ranges and ravines which characterize Callisto’s rugged and battered surface, as well as the great fang-like ice spires which today only survive in the moon’s polar regions.
Oh, we’re not even done yet. The six red and green bars also symbolize Callisto’s six founding populations. The three red bars represent the Australasians (Aussies and Kiwis), Canadians and Japanese, and the green the Brazilians, Irish and Nigerians, and these six groups meet as one, on the white background which symbolizes peace. The flag’s resemblance to the Union Jack is also not on accident, but was a somewhat tone-deaf attempt by the Brazilian-dominated government of Callisto to pander to the Australasians, who historically have never supported the moon’s government. Like everything else on Callisto: it’s complicated.
Next, we have the flag of Europa. Yes, I clearly modeled the flag of an ice world off of Greenland’s flag. But I wasn’t being lazy, I swear. I put thought into this. Let me explain.
So, Europa has been partially terraformed, though one might have to squint to notice the changes, at least from orbit. Remember when I said it was illegal to bulldoze alien ecosystems? It turned out Europa’s subsurface ocean was positively filled with complex alien lifeforms (needless to say, exporting sea food is a major sector of the Europan economy), so this limited how much the moon could be modified from the onset. Not much could really be done about the Chernobyl-esque levels of radiation. Well, magnetosphere satellites were an option, and were successful on Io, but this wasn't an option on Europa, for fear of freezing its ocean solid. Ditto with regards to warming up the moon, though the temperature has in fact been raised. Outsiders never believe the locals when told this. On the plus side, Europa already had a thin oxygen atmosphere, thanks to that friendly ionizing radiation splitting the water-ice molecules into O2, and that's been beefed up through artificial means. So now all you need to live on the icy surface of Europa are a few tweaks to the ol’ DNA (antifreeze proteins, glands which secrete potassium iodide, etc), warm lead-impregnated clothing, KI supplements in everything you eat and drink, and viola!
Not interested in that lifestyle? Well, there’s plenty of settlements built into the ice (deceptively warm and safe from the radiation) and even more are beneath it. Huge, upside-down cities hanging from the bottom of the ice sheet like sprawling chandeliers, well-lit by the glow of huge fusion reactors, which have been a major boon to the local alien ecosystems. Feast your eyes on the strange beauty of the extraterrestrial reefs forming along the outer sides of the chandelier-cities, or if you're starting to miss Earth, the average Europan under-city will typically have more than a few green spaces with simulated sunshine, so that you don't have to worry about not getting your daily dose of vitamin D.
And now I think the symbolism of the Europan flag should be clear: ice above, water below, and the peaceful unity between these two worlds on one moon.
Finally, we have Ganymede, the largest moon of Jupiter and its most populous. Unlike her sisters Europa and Callisto, Ganymede was found barren, so there wasn’t much in the way of restraint when it came to terraforming it, after around a generation of dome cities on the moon's icy surface. As on Callisto, vast amounts of sulphur hexafluoride manufactured on the Jovian Cluster's own "forge-world", Io, was imported to drastically warm up the moon via the greenhouse effect. Together with some choice nuclear detonations (atoms for peace, y'all), this had the effect over several decades of destroying the crust during the “Big Melt”. At the end of which, Ganymede was transformed into an ocean world with no landmasses, and depths far deeper than any sea on Earth. In 2185, around 700 million people live on the subtropical ocean moon in massive, modular cities which float on the surface, some reaching up to two miles into the sky, and many more go down miles under the water, sometimes going as far down as the abyssal zone. Beneath the arcologies are artificial, vertical reefs, which form the cornerstone of Ganymede’s engineered marine ecology. About half of Ganymede’s human population have opted for biomods to better thrive on a world with no
terra firma, resulting in generations of people with webbed feet, increased lung capacity, and even gills, who can live their whole lives without ever leaving the water. Efforts are ongoing to build artificial landmasses on Ganymede, built from rock, carbon and metal harvested from the M-Belt, anchored to the icy and rocky sea floor of Ganymede's core via the same sorts of tethers used for space elevators, and made green through the efforts of an entire army of landscapers and ecoplanners who've cut their teeth designing ecosystems on some of the larger orbital habitats.
I could go on about the sailboat nomads, the uplifted cetaceans or the endemic pirate menace on Ganymede, but this is indeed the "Flag Thread". The dark blue and white stripes are the ocean and its waves, the light blue is the moon’s new sky, and finally there’s the astrological symbol for Ganymede, colored white for the peace, hope and purity of purpose that the moon represents to those who call it home.
(Technically, it’s the symbol for the near-Earth asteroid 1036 Ganymed, but same difference, since they're named after the same Trojan prince. That rock got jacked and stripped for minerals a long time ago anyway.)
