For my story The Pillars of Idrapha I tried to keep a good portion based on real life science. I’m not sure if there’s enough for it to be classified as hard science fiction, but there’s some. The following is basically a “notes for readers who might want more information” post, so if you haven’t first read the short story, you can download a free copy from Smashwords. If you’d like to forge ahead without reading the story, feel free! It’s all spoiler-free science here.
At any rate…
The planet in the story is based on an unconfirmed exoplanet by the name of Gliese 581g. The real-life team who claimed to discover it first (in 2010) refers to the planet as Zarmina, which is the name of a team member’s wife. The planet’s existence is disputed since some later studies contradict the original one. What IS confirmed is the star it would orbit around: a red dwarf star by the name of Gliese 581. It’s about 20 light-years from Earth in the constellation of Libra. Gliese 581 definitely has planets orbiting around it, but so far it’s been impossible to determine the precise number. Because the planet is unconfirmed and most details are educated guesses, I used the guesses which I liked the most. The following is all speculation but there’s a chance it could be accurate:
IF the planet exists, it’ll be like Earth (its Earth Similarity Index is 0.75). It’s actually estimated to be more suitable for vegetation than our own planet. It has one of the highest Standard Primary Habitability scores (on a scale of 0 to 1, Gliese 581g has the maximum 1.0 when Earth itself has a mere 0.72). The planet’s atmospheric makeup is unknown but likely similar to Earth. Thinner perhaps, but similar enough to have plant life and liquid water. Gravity might have an exaggerated effect (at most, 10-30% more than Earth). The temperature depends on the atmosphere – estimated to be a chilly 10 degrees Fahrenheit (-12 Celsius) overall. For this reason, I wrote in The Pillars of Idrapha that a large portion of the planet was icy. Which is due in part to Gliese 581g being larger than Earth to begin with (twice the mass). Wikipedia says Gliese 581g would be a mixture of iron-rock-water and be within the 32-122 degree range (0-50 Celsius). Such a wide range borders on useless when guessing at a specific habitable planet’s temperature, unless you apply each to separate sections of the planet. Earth has a wide range in itself, when you measure temperature by latitude/continent. I went with an environment based on the Appalachian Mountains, since it seemed suitable (given what can be guessed about Gliese 581g so far).
I did take artistic liberties with the local flora and fauna. However, it’s all based on things from another story I’ve been writing, so it’s not overly ridiculous (or maybe it is and I haven’t noticed yet).
“Croatoan” refers to something called The Lost Colony. In 16th-century North America, a small colony was set up on Roanoke Island (off the coast of the US state North Carolina). The governor returned to England to ask for help, and when he returned – three years later – every settler on Roanoke Island had vanished without a trace. The governor found little more than buildings, two graves, and the word “Croatoan” carved onto a tree. The exact fate of the colony is unknown after all these years, although there are many theories (some reasonable, some not). Most believe that the colonists encountered hardships and integrated with a local tribe to survive. Croatoan is still regarded as a popular mystery.
Spaceships don’t seem cost-effective but perhaps in the future it could be. Although the universe’s laws say faster-than-light travel is impossible, I think our technology can find a loophole at some point (within a couple of centuries at most). People have been working on it for a while, including the Tau Zero Foundation. The likeliest propulsion candidate might be based off something called an Alcubierre drive. Essentially, you harness a lot of energy and create a “bubble” in space, which your ship would move through. Instead of having something push you through space (like current shuttles) you manipulate space itself – so your destination is temporarily closer. Some science fiction franchises just say “wormholes,” as the concept is similar but a little easier to explain. Other words and concepts include hyperspace, subspace, and folding space. Taking into account the Kardashev Scale, humans have potential to harness massive amounts of energy (on a long enough timeline). So the massive energy requirements may not matter. Regardless, our current knowledge about the universe is insufficient for “warp drives” and their ilk.
There are other potential options for planets as close as Gliese 581g – “hibernation chamber” technology and slower-than-light-speed travel. One of many problems with “sleeper ships” is time dilation. Since Gliese 581g is 20.3 light years away, it could be possible to reach its system within a human lifespan, despite still taking a long time to complete. A technology which keeps humans in suspended animation might be necessary (and is illustrated in some science fiction films). Along with something like an energy shield to prevent the ship from being damaged by objects (dust, meteors, etc.) in space. For a long journey, conventional physical shielding just won’t cut it. The current speed record for humans is held by Apollo astronauts going close to 25,000 mph (40,000 km/h). Estimates say we aren’t likely to get past 10% of the speed of light (62,000,000 mph) and alas – Gliese 581 is over 120 trillion miles away. That means it would take 80,208 days to get there from Earth (220ish years). If your speed stays constant at that 10%. A working Alcubierre drive is a safer, faster, and more hassle-free method of space travel than going at sublight speeds. So that’s what I’ve used.
Artificial gravity is another maybe-it’s-impossible thing. The “easy” solution is to make the spaceship spin around to simulate gravity, but that’s often impractical. Larger constructs like the Stanford Torus are another idea, but they don’t seem well-suited to be space-going vehicles. I figure that if warp drives are possible, where humanity is manipulating space itself for travel purposes, then it should also be possible to manipulate space inside spacecraft to generate gravity (or increase mass in some way). In the Mass Effect franchise, they explain it through something called a mass effect field, based on a rare material called Element Zero. One of the game’s writers refers to the material as Unobtainium. But basically, some future discovery nets humanity the ability to manipulate mass/gravity, which is plausible enough.
I was originally planning to add this to the back of The Pillars of Idrapha as an “author’s note” but this became a little too long for that. Putting over 1000 words of a “note” after a 7500-word story seems a little weird. But because of the reading I did, I have basic material for future science fiction works as well: plenty of research. And I could always add this post into a future print version of my book.