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Introduction In our universe, the cosmic microwave background was formed approximately 400,000 years after the Big Bang. It was hot, but within a few million years after the Big Bang, it would no ...
Is this physically possible? A non-technological phenomenon visible in the same position of the sky, for 18 hours of a day using the other 6 to do whatever, rise and set, just be impossible to see...
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...
Cooling in space is a well known difficulty. There are many unpleasant consequences like no stealth in space, difficult space battles which turn into a short wars of attrition (because you have to ...
Bernal spheres and other O'Neill cylinders are complicated, maintenance-high and fragile beasts. Someone started to make micro-black-holes and put them in asteroids, in order to have 1 to 10+km roc...
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 been looking over the internet and on here to find some kind of evidence for this, but nothing conclusive, so I was hoping for people with a better understanding of smelting, chemistry and phy...
Here's something I've never noticed anyone asking when it comes to wormholes/portals: If they allowed air to pass through them, how fast would the wind be? Should atmospheric pressure differences b...
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...
An interstellar traveller stands upon the surface of an alien planet beneath the light of an unfamiliar sun. The planet upon which he stands orbits one star of a binary system in which one is a G-c...
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...
So, I am writing a comic which will perhaps grow into an entire series about a group of aquatic heroes. One of those heroes is a monster size aquatic lizard. The story of how this lizard came about...
I've seen some posts here (for example this one) for the effects of certain sizes of impactors, but I'm not finding any definite answer and all my google and google scholar searches have not turned...
The one-electron universe postulate, proposed by John Wheeler in a telephone call to Richard Feynman in the spring of 1940, hypothesises that all electrons and positrons are actually manifes...
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 ...
Would it be possible for a nation with 19th century to very early 20th century technology and history and hot desert climate to utilize solar power for electrical generation as a substitute for coa...
I travel back in time to the Big Bang in my time machine. I am equipped with all the present day equipment I need. I locate the infinitesimal 'point' where the Universe would come into existence an...
A type 1 civilization is defined as a civilization that can utilize the maximum amount of energy equal available to its entire planet, roughly 1017 watts for Earth. This is equal to the amount of ...
How would the phases of the moon change depending on the inclination of its orbit with respect to its primary's equatorial plane? Earth's moon has an orbit that is rather close to the ecliptic, but...
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 ...
I'm imagining a near-future world where a process can be undergone that will halt all future aging of the body, but the approach causes infertility. Those undergoing it will not have (biological) ...
How much force/energy is required to punch someone so hard that the person is sent flying at the speed of sound? Also, what can you compare the force/energy to? For example, is it comparable to a ...
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...
This question draws on an old idea but it is different. The original question is, "If everyone in the world jumps at the same time, will the Earth move?" My question is,"If everyone in one hemis...
We know that Mars has a reddish color, because its ground consists of iron-based compounds. The moon is grey-whiteish because it consists mostly of silicon-based compounds. What element should the...
In a world of superheroes the job of blacksmith is given to the very strongest of them. Question Is splitting an atom in a human-scale piece of work by using a human-scale tool even theoretically...
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...
Little side project on fantasy story with dragons (or wyverns to be exact, but they're equivalent for the purpose). I have dragons roaming the country side, laying waste and ruin in their wake. As...
My heroine has been stabbed - run through the abdomen by a foot-long dagger - and is bleeding to death. She is currently crawling toward her salvation through a very cold place. She is magically ...
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? ...
There are many questions on Worldbuilding about what item(s) a time traveller should take back in time in order to alter past events or even simply to survive. There has never as far as I know bee...
Most works of fiction have quite imaginative views of time travel. Mighty machines that teleport in time instead of space. Gaping portals in space that take you to another time. Mystical beings wit...
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,...
Background A large colony lives in the Antarctic in a network of bases. They have so far evaded the dreadful worldwide plague. When they venture outside their base they don their climate-proof ...
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'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...
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...
A perverse incentive is a reward system that has the opposite effect to the one intended. In Hanoi, under French colonial rule, a program paying people a bounty for each rat tail handed in wa...
Background In my hard sci-fi settings, there is an advanced Type II Civilization, that are progressing toward Type III Civilization (yes, I am referring to Kardashev Scale). They are sprawling acr...
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...
I'm building a moderately hard scifi future setting that focuses on space and land warfare and I'm trying to decide what would be the most realistic from an engineering standpoint of artillery tec...
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...
I'm sure most worldbuilders will have heard the aphorism that in space "Everyone sees Everything", or that "There Ain't No Stealth In Space". I'd like to propose a possible solution to this. Th...
My question is pretty basic, would square thrusters and RCS ports have any real drawbacks over round ones? I know that angles on windows for airplanes is a problem because of the pressure, so I don...
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...
Human physiology is adapted for life at 1G, but planets colonised by future humans will likely have different surface gravities. What is the range of values for surface gravity that humans can com...
This question has been rewritten to incorporate all clarifications. On Earth, half the planet is illuminated at any time (let's ignore eclipses). Axial tilt lets day lengths vary, but over the cou...
I'm writing a cyberpunk novel where one of the characters has an augmentation that allows them to echolocate. The idea is that there is a device on the center of his forehead (is there a more opti...
I have been working on a sci-fi story for a little while now, and have recently discovered that I made a very big error in assuming the position of Eris. The main issue is that I had forgotten to t...
If I was affixed to the surface of some solid spherical body in space (so as to ignore effects like me floating away), would it be possible for me to throw a tennis ball so that it went into orbit ...
