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For my hard sci-fi story, I would like to have a planet similar to Titan (very cold, nitrogen atmosphere, methane seas) but with a surface gravity in the region of 1g. Could this occur, or would th...
In my scifi setting small utility robot swarms are used for many purposes. I'm currently trying to estimate how much energy such a swarm would need to operate. Since biology, robotics and nanotechn...
What sort of force would a railgun need to produce to have a measurable affect on the trajectory of a large spacecraft? In the scifi book I am working on the primary craft of the story is a milita...
Lego representations of Earth have been made at various scales, for example this one: Suppose Slartibartfast made a full-size Earth from Lego (including the oceans being represented as solid blo...
Prior to the Cambrian, there have been three separate ice ages--the Huronian, from 2.4 to 2.1 billion years ago; and the two Cryogenian ice ages, from 720 to 635 million years ago, split in such by...
In the story Wang's Carpets (and part of the novel Diaspora), Greg Egan sketchily describes a high-dimensional universe which contains no analog for light, such that the aliens who inhabit this uni...
I'm working on a computer program which generates realistic planets for worldbuilding purposes. I've run into an issue with calculating my planets heat loss. While radiogenic and tidal heat generat...
How do I calculate the thickness of the upper ice layer on cold ocean worlds like Europa, Enceladus, and Ganymede? I'm asking this for a programm I'm currently writing. The given/known quantities ...
Obviously, if available, atmospheric oxygen is a great source of energy. However, I'm surely not the first worldbuilder who wants an alien species which doesn't depend on it (whether due to having ...
In my world, physics works exactly like on Earth, except that there is a narrow, 400 foot tall magical column sticking vertically out of the ground, which is magically always extremely cold -- I'm ...
A civilization wishes to create a wormhole connecting its universe to a universe with a different spacetime metric. For instance if we describe a timelike dimension with $+$ symbol and a spacelike...
I was watching a program about the New Horizons space probe and was fascinated by the new revelations about cryolava/cryomagma, and the amorphous planes covering Pluto(98% nitrogen ice). I'm wond...
I know that objects with lower mass tends to orbit objects with higher mass, is it possible to have a Moon sized planet who's mass is so heavy that an Earth sized planet orbit it as it's Moon in a ...
Note: This is different from the previous question Building a full-sized Lego Earth - what would it look like at various levels?. In that case it was about making a solid full-size Earth from Lego ...
I have seen many people discuss in this community on how a plasma gun ought to be made. But only a few mention the Powergun from the Hammerverse. I ask if this design will work. Can the bullets ...
Many science fiction stories, movies, and shows involve characters undergoing explosive decompression, the technical term for a rapid drop in pressure, usually all the way to a vacuum. Frequently,...
Imagine that humanity builds mining facilities on the moon. We know that the moon has Helium-3 which could be used as fuel for fusion reactors. Also, there are a lot of other resources which could ...
In a world set many years (At least a generation or two) after a near extinction level nuclear event, how could a recovering population set up a internet or internet like service? Key points I'm i...
In a world like ours in the 1980s, but which for whatever reason does not use any form of electricity. (Either it does not exist or batteries and generators etc have not been invented.) For purpos...
In the far future the posthuman successors of mankind have disassembled the stars and live on ultra slow and ultra efficient solar system sized computers, Matrioshka Brains. The last enemy of intel...
Back home, Earth had gone through an impact-coalesce cycle only once. Since then, its core has been 84% iron, 6% nickel and the rest being labeled by The Encyclopedia of Earth: A Complete Visual ...
The details don't matter, just that a large fraction of people have died (let's say 90%) and society has completely collapsed. It's only a year or two later, and people have started to gather toge...
In the DC comic book universe, the Vega System is a solar system around the star Vega (Alpha Lyrae), which is depicted as having dozens of habitable planets. While it seems to be an implausibly lar...
Currently writing a scifi novel and am trying to do the math to establish time frame of the lore. The main points are that in 2068 CE Earth sent a generation ship to colonize Proxima Centauri. They...
I'm looking to create a species of marsupial that is heavily K select, which is to say they put significant effort into raising their young after birth (both of them :P ) in which both the male and...
On the earth today most animals use a two sex mating system where male and female provide the same amount of genetics to the resulting offspring, despite the fact that in many cases the female prov...
I want to render impractical the deployment of satellites by exploiting the Kessler syndrome. Why, you ask? Maybe I'm an evil overlord and I don't want those pesky satellites flying over my lair. ...
I have a Gas Giant with 13x the mass of Jupiter. How many satellites of Earth size and mass can it hold safely in its orbit? Edit: This gas giant lies smack dab in the middle of its parent star's ...
Bob the time traveler has a problem. He went to 75,000,000 BC to get some dinosaur eggs (don't ask) and his time machine re-combobulator broke and a big chunk is missing. Fortunately he can still ...
It has been determined by observation of the stars that the gravity on Flat Earth is due to it accelerating upwards at 1G. This is what holds people and objects to the surface. It has also been det...
I want to popularize the following or a similar belief. In many thousand years people will travel back in time to give us an afterlife, if we make it possible, by going the steps, that will lea...
I want to put a circular city in geostationary orbit. The city will have a radius of 20Km. I was thinking of using quantum trapping/levitation to achieve this. Here's what quantum trapping is: ...
EDIT Why this is a world-building query. If I had framed this as, "In my world where magic requires the expenditure of energy, a powerful wizard decides to open a path through a large lake,etc. Th...
In my fiction I'm setting up a civilization which uses Laser Propulsion for moving things between bodies within a solar system (assume Earth/sun analogy). Laser Units have been set up anchored to a...
Suppose that there is an alien spacecraft travelling towards the Sun. This spacecraft is similar in design, size and power output to Voyager 1 and Voyager 2 as they were immediately after launch fr...
I'm currently outlining my science fiction novel which deals with humanity reaching Type 3 civilization status. My goal is to place an emphasis on hard science fiction while featuring fantastic tec...
Pretend I'm writing a story about a world exactly like our own. Real world physics, no magic, modern technology. Suddenly an eccentric world leader comes up with the idea to replace the melting gl...
A fictional starship that I am designing functions via a form of Bussard ramjet that uses hydrogen from the interstellar medium as reaction mass, not as fuel. In order to accelerate the propellant...
I was having fun reading this article about making cement on the moon when I asked myself (and now you), is it possible to make a suitably high-compressive-strength cement on Mars? Since concrete...
I'm writing a rough sketch for a book about a world where people sorta violently and suddenly get barely working superpowers. That is every time each person uses their power they run the risk of ki...
I'm thinking of a character that has the magical ability to transform parts of his body into technology, similar to Generator Rex or Bleeding armor iron man, but only with the technology that he "u...
So the background is simple: in the modern day a CME (coronal mass ejection, a solar flare that has escaped the sun) hits the Earth and destroyed all the electrical equipment causing planes to cras...
The black hole question reminded me of an idea I wanted to implement at some point in a space campaign, but didn't go forward with because I was unsure whether it's merely statistically very implau...
Summary The main idea behind the "cuboverse" is that spacetime distances are measured by (something close to) the sup norm or infinity norm. Under this norm, spheres (the set of points at a fixed ...
How would I calculate if it is possible to have an eccentric enough orbit around a gas giant to dip the periapsis some depth(how deep?) into the atmosphere of a gas giant like Jupiter or Saturn and...
I'm designing a world with earthlike gravity where the human colonists are intended to live on top of a gigantic shield volcano as tall as Mount Everest. What would the pressure be at the bottom? ...
Pathogen Note: For the purpose of this question I define a pathogen to include viruses and/or bacteria. Edit: I don't exclude other biological agents such as fungi that might have the same effect...
They do not necessarily meet humans and try to interact with them. This question is more about the technical possibility/impossibility of 4D aliens being able to "analyze" the inner structure of ou...
I've looked around the forum but didn't find an answer to this particular question. In short, what food could realistically be produced in a space station assuming current (or near future) technolo...
In my story a man who works in Military Intel gets early warning that a nuclear attack on his base is inbound. He abandons his post, grabs his wife and kid from on base housing, and books it out of...
