I'm writing a science fiction series (with elements of Lovecraftian horror) which is set on an alien world whose resident species has just begun making serious headway on manned space travel throughout their solar system. Shortly after the discovery of a treasure trove of nigh-godlike ancient technology, outside forces involved with the making of that technology send the sun into a two-century countdown which will inevitably end in a supernova. The next two hundred and twenty-nine years are basically a marathon run partaken by countless nations and organizations, most of them desperately working to exploit the tech to protect their world from the substantial changes its parent star is going through. An age of technological wonders, overshadowed by a grim sense of urgency. One of these projects, the one that's headed by the story's protagonists, is essentially a space-ark meant to house millions. Rather, it's the result of what happens when someone follows up on the idea that, instead of building a massive ship and somehow getting it into orbit, they could use the moon itself as a ship, riveting an FTL reactor to its now-gutted interior and building colonies expressly designed to withstand such a journey. Basically, someone said "Let's turn our moon into the Death Star, only instead of a death ray, let's give it a massive warp drive and the ability to sustain a hundred million people for god-knows-how-long until we reach the next system!" I'm aware that this fiction, and that in fiction, pretty much everything is possible - but I want this to feel believable. And a project spanning two centuries, the result of which is meant to be fired off at superluminal speeds while housing a nation's worth of people, should feel like a monumental effort rather than a Deus Ex Machina for a species facing extinction-by-supernova. The point is, what should I be sure to take into account to avoid giving my readers a sense of "this is just plain stupid"?
It sounds really interesting to me. It reminds me of the villains' star of death in an anime series i watched as a child named Space Carrier Blue Noah or something. Their sun was about to die, so their leader converted the moon to a satellite that carried millions of their people across the galaxy to earth. As for the believable part. If the star is going supernova in 200 years, then the planet they currently live in wouldn't be habitable for those 200 years. The process for a supernova starts roughly 10.000 years before the BOOM and by that time the star would be a red giant. So if you want it to be scientifically accurate, you could say the advanced aliens have a technology that can put the sun on overdrive making it go supernova in X time and they will use it 200 years from the time they said they would. In my opinion what you have thought so far is very interesting and you can make it great without sticking to every little scientific detail.
A story concept means nothing. What matters is how you write it: the characterization, the flow, the imagery, all of it. There's absolutely no benefit in asking what other people think of the concept! They'll either say,"Sounds great," or, "it sounds like a ripoff of..." If the idea stirs you, write it. Then ask people what they think of the final story. After they tell you what they don't like about it, revise it, usually several times, until you're happy with it or until you throw up your hands and say the hell with it. Stupid or brilliant is all in how well you sell the idea with your writing. Please read What is Plot Creation and Development?
Habitation: Don't hollow out the moon. It will lose all of it's structural integrity AND you'll lose all of that mass so the moons low gravity would become NO gravity. Build domes on the surface and caverns that run into the ground. Energy: Moon dust contains significant amounts of Helium-3 (3He) that can be used to create vast amounts of clean nuclear energy. So, make nuclear reactors. Water: The moon contains a decent amount of water but not enough for millions to use for potable, grey and black purposes. I would suggest you do some research on the International Space Station to see how they deal with this. Food: Farms inside the domes would probably be the best option. UV lighting comes to mind. Hope that helps. I'd love to see what you come up with if you use any of this.
The stellar evolution of an F-type star like the sun means that our world won't be habitable in just over 1 billion years (and it is destined to evolve into the red giant stage in 5-6 billion years, so lots of time to spare). In 500-600 million years the different combinations of carbon and oxygen vital to photosynthesis will decline, and we'll lose forests and trees. Life will become simpler and simpler as it adapts to harsher conditions. Helium gathers at the core of the sun over time, so it becomes more luminous (~10% brighter every billion years), which will have a huge impact (and it probably explains why complex multicellular life didn't come about until recently, in the last 700 million years or so).
What you are saying is right, yet irrelevant to the op or my post. The process of the "death" of a star (in our scenario a star big enough to go supernova) starts when it can no longer produce helium and starts producing heavier elements (iron and carbon). By the way, our sun is not big enough to go supernova, it would need to be 1,5 times it's size at the least.
You still have a gravity ell to contend with. You have to lift millions of people, and all the consumables they require, out of the planet's gravity well. A daunting task, to be sure, but what is is compared to the engineering required to convert the moon to a structurally sound vessel, AND transport those same humans and consumables to the moon, AND accelerate the moon across interstellar distances. Also, all those people will no longer have a star to provide energy. A moon-sized ship requires more energy to sustain a habitable environment than a few city-sized vessels. City-sized vessels would make more sense from a propulsion perspective as well. If you're going to move a planet, move the home planet instead, At least then you won't have to transplant the entire ecosphere offworld first. If you're going to justify a project of this kind, you need a better grasp of the relative scales of the habitation space taken up by the population against the mass and volume of a planet or planetoid. I'm not saying there is no possible way to justify the task as you've presented it, but it would be a very hard sell not to peg the BS meters of much of the science-aware SF community. On top of that, you'll have to overcome the raised eyebrows (and bile) of anyone who remembers the truly awful "science" fiction series Space: 1999.
I had written more since you got me on red giants going supernova...then I checked it out, and it turns out red giants can go supernova (not all, but apparently some stars do enter a red giant phase prior to supernova).
The process of death for a star depends on it's size. If they are large enough or they are able to accumulate enough material from a nearby stellar body either through accretion or via a merger , then they suffer a gravitational collapse and an explosion occurs known as supernova. If they are not large enough, they simply condense into a white dwarf and eventually a black dwarf. Red Giant is the state of a star where the hydrogen fuel has almost run out.
