Questions tagged [physics]

For questions regarding the physics relevant to fictitious worlds. General physics may be off-topic.

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How to accelerate time?

Something in a spaceship, a box, an area in the space, whatever, that experiences a faster time than the rest of the universe. The opposite of the well known twins paradox. How could be that the twin ...
3 votes
6 answers
1k views

Countering Free-Electron Lidar?

In my hard sci-fi setting, there is a technology called free-electron lidar, usually deployed in space. Edit: Essentially, it is a lidar with the ability to change its laser frequency. One free-...
3 votes
2 answers
92 views

what would the wind patterns on a world that has a constant "midnight sun" [duplicate]

I created a world that's axial tilt is on a constant 45 degree angle in the northern hemisphere it would look something like this. The problem is I can't figure out how the wind currents would work. ...
45 votes
10 answers
11k views

If humans were the size of ants could we have campfires?

Had a dream that I was the size of an ant and I was being chased by spiders and other small horrors. I created a campfire and was able to scare off the insects. When I woke up I came up with a TTRPG ...
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7 votes
6 answers
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Spear-thrower that doubles as a hatchet?

It seems like civilizations that used the atlatl usually switched to a different melee weapon, so the atlatl and its darts were more exclusively ranged weapons. If I am designing a civilization that ...
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5 votes
3 answers
115 views

Would a Single Propeller Back Configuration make more sense for an Anti-Gravity Airplane then a tractor configuration?

I have a setting that is pretty similar to Earth. The tech is at least around WW2 with some steampunk fantasy sprinkled here and there. A global war is about to break out. My civilizations need an ...
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2 votes
2 answers
115 views

What would modern color wheels look like if the human eye saw fewer/different spectral colors?

The typical human eye can see wavelengths between 350nm and 750nm. In 1666, Isaac Newton used a triangular prism to split a beam of white into a rainbow and then define the first color wheel. Fast-...
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3 votes
3 answers
247 views

Coilguns as spaceship thrusters second attempt

This is a second attempt for this question, the first time i put in too many different things that ended up derailing the question. I'm in the early stages of designing a scifi game and want to use as ...
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4 votes
1 answer
116 views

How strong does a rope need to be to hold back a harpooned elephant?

Relating to a previous question, say that a group of people is hunting an elephant-sized land animal. For some reason, this animal needs to be harpooned so it won't simply run away to an inhospitable ...
8 votes
10 answers
2k views

Logical/Scientific Explanation for Umbrakinesis?

I'm working on a story where the characters have elemental-based powers based on natural material/materials/phenomena found in nature. So far, each of the powers makes sense on a physical level, since ...
12 votes
4 answers
2k views

Mirrors used for focusing sunlight in outer space - could they be automatically oriented towards the sun using sun sail rudder, like windmill rudder?

To be most effective, a windmill must face into the wind. Some windmills achieve this with a passive yaw system, where the wind automatically adjusts the direction the windmill is facing, often with ...
2 votes
1 answer
201 views

How thick would a mattress made of flower heads need to be to stop a child falling down a 200-ft deep hole from getting seriously hurt? [closed]

How thick would a mattress made of flower heads need to be to stop a child falling down a 200-ft deep hole from getting seriously hurt? The child is 5 years old and of an average weight, the flowers ...
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2 votes
1 answer
153 views

Achieving VTOL by blowing wind directly in the wings? [closed]

So in the story I'm developing there's a mobile base of sorts where I tried to incorporate all of the different methods of mobility that i could think of, for the sake of redundancy (redundancy is ...
5 votes
1 answer
83 views

Are there any atmospheric properties that might make iridescent clouds more common on a different planet?

I'm designing a few planets and the life that could inhabit them, and was wondering if an uncommon Earth phenomenon like iridescent clouds might be more common on a planet under different conditions. ...
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35 votes
6 answers
6k views

What are the effects of making a woman as light as a duck? [closed]

With a pinch of handwavium, Clarabelle the witch causes an accident. She became permanently as heavy as an ordinary duck, while her body remained the same. Her density was forever altered. She is five ...
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1 vote
1 answer
162 views

Shapes of Space-Time

Ok let’s get the legwork done first. A common way to visualize our current space-time is as a 3D grid. The lines of this grid are perfectly parallel until a significant amount of matter causes them to ...
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4 votes
1 answer
195 views

How much do tunnels extend blast waves from explosives?

Someone recommended this SE for this question, since I'm asking it to help a friend's setting, where dwarves and goblins fight underground with explosives. After asking if it was OK, I cross-posted ...
8 votes
3 answers
551 views

Could a very light humanoid creature throw a javelin?

My story has a creature that is vaguely humanoid in shape and lives on an Earth-like planet. However, the creature is smaller (dingo-sized) and only weighs around 35 pounds. Like humans, these ...
0 votes
1 answer
47 views

Explaining My Planet’s Weather

Alright so my planet is very similar to Earth, but slightly more unstable. Both geologically and atmospherically speaking. It orbits an orange star, slightly larger and more “angry” than the sun. It ...
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3 votes
5 answers
832 views

Could vacuum armour protect vehicles and people from explosions? [closed]

If you have a <1mm thick layer of vacuum inside an armour plate, be it for vehicles or body armour, wouldn't it stop explosive shockwaves from penetrating through the armour? This is, of course, ...
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5 votes
2 answers
255 views

Is colonization through underground tunnels possible? [duplicate]

I am thinking of a scenario in which a tunnel linking Hungary to Morocco is built around the 1500s by the King of Hungary in an attempt to colonize Morocco to get a border with the Atlantic ocean. ...
2 votes
0 answers
70 views

Question on how my civilization can deflect a comet on a decaying elliptical bringing it into a collision course with the earth [closed]

My novel requires that a comet, in an eighty-year elliptical orbit around the earth, changes trajectory due to a friction-like mechanism, resulting in orbital decay that will impact the earth within ...
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-1 votes
2 answers
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What's a clever science way of moving a large boulder blocking a bridge [closed]

I have five characters stuck on one side of a bridge with two cars. The bridge is blocked by two boulders, one for each lane. They have been placed there by an excavator or tractor, so not enormous, ...
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3 votes
1 answer
182 views

If a very hot blade were used to cut off a limb, would it cauterize, and if so, would it be less lethal than a regular wound? [duplicate]

Okay, so first post here, howdy, nice to meet you! I’m working on a story that involves a woman on a vendetta who decides that she will begin trying to avoid killing people, however mutilation is fine,...
1 vote
1 answer
101 views

Can an alternate physics system be devised in which the weak force is reduced or eliminated entirely?

Like, is there a modification to the Standard Model you could make, or some sort of alternate gauge theory that only unifies the strong and the electromagnetic interactions? Edit: I am not asking for ...
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9 votes
9 answers
4k views

How much energy would it take to keep a floating city aloft?

My fantasy novel features a floating city. I wanted to know how much energy (joules/second) it would take to keep a floating city aloft, but the definition of joules has "distance displaced" ...
1 vote
4 answers
417 views

If I have a zero-width, infinitely-strong sword. Do I need to be worried about radiation when I cut things? [closed]

Would the blade cutting through the atoms in the target material create unstable isotopes and would that be a concern for the wielder?
5 votes
3 answers
940 views

What would realistically happen after a gravity magic spell is cast?

I have read dozens of books where gravity magic is a thing. It ocurred to me, while reading one of these stories, that every version of a gravity magic spell that I have heard of, is missing something,...
-1 votes
2 answers
124 views

Would would an undiscovered element show up as on a light spectrum analysis? [closed]

All elements, when hit by light, reflect it at varying frequencies and by looking at the frequency of the reflected light it is possible to find out the elemental composition of an object, even from ...
11 votes
2 answers
1k views

Would radioisotope thermoelectric generators be more effective on Titan than in space?

Since radioisotope thermoelectric generators (RTGs) operate by turning the flow of heat into electricity, and Titan's atmosphere can absorb heat faster through conduction than a vacuum through ...
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4 votes
5 answers
1k views

How much gasoline does there need to be to ignite and cause a fire in a small shed? [closed]

I'm trying to write a story where a gas leak causes an explosion. How much minimum gas would there need to be for a small shed/small room to ignite when a match is lit in there? The doors and windows ...
-1 votes
3 answers
142 views

Beam Convergence?

I have a character that can release laser beams from both his hands and i just want to know if he can shoot these 2 lasers at a single point and converge causing it to become a singular stronger beam. ...
3 votes
1 answer
481 views

Replacing the sun with an type A star (Fomalhaut) in a fantasy solar system where there is an habitable planet

Lets says there is a planet in the goldilocks zone of a type A star (luminosity of 16 and mass of 1.9 (like the star Fomalhaut)) How far would the type A star need to be from the planet and how would ...
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3 votes
3 answers
377 views

How effectively recover enriched uranium from nuclear impact site?

In the world(not Earth, but eath-like), I am building there was a nuclear exchange recently. Recently, I mean 25(subject to change) years into the past. I am describing a small clump of cities near ...
0 votes
2 answers
129 views

Which numeric base should I use for universal measurement unit prefixes? [closed]

I'm developing a story where Earth is obliterated by an asteroid and the small mars colony collapses into chaos shortly after. The last survivor enters a criogenic chamber for indefinite amount of ...
1 vote
3 answers
158 views

Is there any plausible way for a creature to fly in the way characters like superman does? [duplicate]

I'm making a superhero comic a little more grounded in reality. One of the characters in it is a genetically modified soldier who has abilities very similar to superman. How would such a character fly ...
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4 votes
3 answers
225 views

How long would it take an iron key to rust away

I'm writing a fantasy story where an iron key was thrown down a deep well. The key needs to rust away completely in order to reform in another place. So how long would it take for an 8 cm ornate ...
1 vote
2 answers
111 views

Worldbuilding (Merge) Conflicts. Pseudo-Science behind Psychic Barriers? [closed]

I am trying to tie together my mythos with a relatively consistent set of psychic powers, but I'm starting to think that may not be possible. I'd like to preface this by saying that I intend to ...
1 vote
3 answers
115 views

would this Lenz law based inertial dampener work?

Basically this "Inertial Dampening" systems works like a magnet falling though a cooper pipe https://youtu.be/5BeFoz3Ypo4 But replace the falling magnet with a crew capsule surrounded by a ...
10 votes
5 answers
524 views

Practical speed limit for torch-ships

This is for a sci-fi universe depicting an interplanetary civilisation using fusion torch-ships. Think "1G for days". For a run to Neptune at 1G the peak velocity at turnover works out to ...
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18 votes
8 answers
3k views

Medieval Footwear in swamplands

In my world, people live in a swamp where the ground is consistently covered in at least 4-5 in of water and occasionally higher, reaching up to the knees. My Question is what kinds of medieval style ...
-1 votes
1 answer
184 views

Shape for injector spikes that provide the best seal

In the near-future story I'm working on the protagonist is prepared for a wide range of possibilities, including getting outnumbered and surrendered. For that possibility i though about a Banshee Box ...
3 votes
1 answer
115 views

Dealing with extreme heat and pressure in an underground colony on Venus

A colony has been constructed by robots for human habitation deep under the surface of Venus. They are totally sealed off from the surface, and the galaxy beyond, and live like a ship in a bottle What ...
2 votes
3 answers
137 views

Would the backblast of a rocket launcher be damaging to robotic soldiers?

So in the future, we have robotic (humanoid) soldiers that do the fighting regular human infantry used to do. Now, the backblast of a rocket launcher in real life can definitely kill someone. If there ...
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5 votes
2 answers
282 views

What, if anything, would a person-sized vacuum sound like when being emptied and filled?

A character in my setting has the ability to, at any time, turn incorporeal and back. When she becomes a ghost, it's instantaneous, and when she turns back to flesh and blood, it takes about a tenth ...
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6 votes
2 answers
695 views

30 g kick to an entire planet, but only for extremely short duration [re-scoped]

I plan to subject an entire earth-like planet to about 300m/s^s acceleration, what is the shortest duration I can get away with for non-scientists to realize something has happened, without everyone’s ...
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2 votes
2 answers
114 views

Could human-powered aircraft be practical on a low gravity world?

On a world with a third of Earth’s surface gravity, with an atmosphere with the same pressure, makeup, and temperature as Earth’s, could pedal powered aircraft be a viable and easy method of ...
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2 votes
5 answers
413 views

Magic - Applying Physics to Runes

I'm making a magic system, unsurprisingly, based on runes. - Basic concept: Scribe a rune (e.g. a lightning rune), apply force to it (e.g. shoot it with a cannon), boom - lightning bolt. - Problem: I ...
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0 votes
3 answers
210 views

Would an air burst nuclear weapon make a crater? [closed]

In specific it would be a 300kt warhead detonated around 3000ft above the ground.
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3 votes
2 answers
123 views

Is my map of prevailing winds on a binary planet realistic?

My binary planet consists of a Venus sized earth-like planet, tidally locked to a mars sized “super mercury”, with their centers separated by about 7 Venus radii. I know the coriolis effect would ...
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