Questions tagged [physics]

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

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4
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1answer
38 views

How to block extreme winds on a stormy planet?

Assume that you have a planet mostly covered in water (about 89% of the surface is water). There are a few connected continents in the middle of the planet. If the rotation of the planet is slow, say ...
12
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8answers
3k views

The Bean Gun. Is it plausible?

Ok, since I'm tHe BEaN dELiVerY mAn, I need an appropriate weapon. I want a (you guessed it) bean gun. I want something that could launch beans at a lethal speed. However, I don't want the ammo to ...
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16answers
6k views

How to avoid boats on a mainly oceanic world?

On an Earth-like planet with clustered continents and large oceans, like Pangaea, the easiest method of travel would be boats. However, I am looking to avoid humans using boats. I define a boat as ...
5
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3answers
225 views

How quickly will water displace if an object levitates above it?

I'm writing a sci-fi story in which levitation is a thing. Newton's Third Law still holds, so if a 10kg object with a $0.5m^2$ footprint was levitated, the floor below it would feel approx $mgA^{-1}\...
11
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6answers
367 views

How would you arrange wormholes throughout the galaxy so that they don't violate the Chronology protection conjecture?

Any form of FTL, including traversable wormholes, allows backwards time travel. My world has traversable wormholes, so I just bite the bullet and say yes, anyone with the ability to use wormholes can ...
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2answers
207 views

Would a Micro Black Hole locked in Mirror Storage have a felt weight?

I understand that Black Holes, even the small ones, are very dense and heavy. Even a micro black hole will probably weigh as much as a skyscraper, a few million tonnes. I then saw a starship ...
1
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0answers
51 views

A magic system based on Force, Impulse, and Momentum [closed]

I would like to create a magic system whose laws are based on Quantum Entanglement, force, impulse, and momentum. The people who practice this magic are an oppressed group. Some of their forms and ...
2
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2answers
127 views

How bad is my runaway fission reaction?

During WWII in an alternate universe, the nuclear bomb is being developed. Interestingly, radiation amounts are far higher than predicted when enriched. Unbeknownst to the scientists, highly enriched ...
8
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4answers
626 views

What is the minimum Radius required for an O'Neil or McKendree Cylinder?

This is a follow up to this question. Dimensions of an O'Neill cylinder with gravity and coriolis force like surface of Earth I read different things like football field length, 200km or 4000km.
3
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2answers
109 views

Is it possible for a medieval-style SCA/LARP armor to shatter? If so then how?

I was writing a story where a character wearing armor constructed for SCA / LARP has his armor repeatedly heated (e.g. walk through house on fire) and cooled (e.g. liquid nitrogen spray, a barrel of ...
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4answers
175 views

What would a world look like if everything was a billion times more massive? [closed]

All atoms are still the same size/mass - it's just that the Earth, people, grass, bugs, etc - everything is more massive by a billion times. So since the Earth would be a billion times more massive, ...
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0answers
32 views

charge moving in a wire; or not [migrated]

A current flowing through a wire creates a magnetic field. A current flowing through a wire represents electrons moving very slowly in the wire. A wire contains electrons. If I have an isolated ...
6
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3answers
143 views

Once you've calculated the tidal heating of your moon, how do you calculate the surface temperature?

Let's say you've calculated the tidal heating of a moon in Watts using the method described in How does one calculate the tidal heating of a satellite?, how do you then convert this to surface ...
3
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3answers
110 views

Energy conversion and how it would shape society

So in my world, there are different types of elemental magic. Regarding lightning (electric) magic, it functions by the user converting any kind of energy (say, kinetic) into electrical energy or ...
2
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1answer
82 views

What effect does an extremely high-powered laser have in atmosphere? Is it viable as a man-portable weapon? [duplicate]

Let's say that you are put in charge of man-portable weapons development for a civilisation so advanced that almost anything is possible. You decide that a "dial-a-yield" pulse laser system ...
-1
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1answer
75 views

Coilgun vs Railgun in Space Vacuum [closed]

So, I am creating a Scifi setting as part of a personnal project, and was planning to use Rail and Coil gun as main armament for the human race. Other answers on this site have provided answers when ...
2
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3answers
214 views

What's the best fuel for a lander?

For background, read my question. What would be scientifically the best way to get the lander out of the atmosphere? It is 12ft high and 15 ft long. It's about 11,000 pounds of dry weight (tell me ...
1
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3answers
127 views

How can we gain control over the four fundamental forces [closed]

I was wondering is there someway for us to control the four fundamental forces or control matter directly. Would we be able to do it biologically or do we have to make some machine of some sorts.
6
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4answers
276 views

I need to destroy the Earth. Is this what it might look like?

This is a small but critical part of my story; I need to kill off most of humanity (leaving a 5- or 6- digit number of survivors) and render the planet uninhabitable long-term, but survivable for a ...
5
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1answer
239 views

How fast do you have to be to punch through a steel door?

Assuming the person is durable enough to not break his hand, how fast would he have to move his fist to punch completely through a solid steel door that is 1 inch thick?
0
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0answers
41 views

Single Time Zone in a Galaxy [duplicate]

This follows up the Single Time Zone on a spherical planet. Suppose now we have many habitual planets in a Solar system or in a Galaxy. How does it work to set up a Universal Time? Will it be ...
6
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4answers
203 views

Existence of elementary particles in an hysteretic space-time

I am toying for a while with the idea of an hysteretic space-time. Hysteresis is the dependence of the state of a system on its history. Though it could make for some interesting twists in the world,...
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2answers
112 views

Does infinite energy being spread evenly amongst infinite volume result in overheating? [closed]

I have an infinite black void. Due to the fact that it is infinite, no matter how much finite energy I dump into it, heat will not continue to accumulate as it is an infinite amount of volume and it ...
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5answers
3k views

Huge lasers firing into orbit and eye damage; how to prevent mass blindness?

There are a few uses for ground-to-space lasers in science fiction settings. One is the laser broom, used to shoot space debris until it deorbits and burns up. Another is beam propulsion, or sending ...
6
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1answer
156 views

Could a 3+1 dimensional universe have a spacetime curvature that never reduces to Newtonian Gravity?

I was thinking of a universe with 3+1 dimensions, in which the spacetime near a massive body is curved. If this universe was empty of energy and matter then the spacetime geometry would reduce to ...
2
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1answer
100 views

How would ground pressure effect cyborgs of varying weight?

In the world I'm working on human civilization is mostly dead and the planet is gripped in nuclear winter. Most of the people who've survived are cyborgs. While these cyborgs are still humanoid they ...
4
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2answers
298 views

How to build an airport at 30,000ft?

What differences might an airport runway and landing differences have on Mount Everest for airplanes at 30,000ft? The drawn line in the pictures is about 2 miles. This would be practical for hand ...
4
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1answer
84 views

Precise localization of another ship in a Orbit-to-Orbit scenario

Here is the scenario. Two ships are orbiting an uninhabited planet (no sensors on the ground and no other satellites in orbit). At time zero they are far away (let's say 50,000 Km apart) following ...
21
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8answers
5k views

What would happen if you blasted a hole through the earth?

During a battle between two extremely powerful space wizards, a beam of magical lightning has blasted a perfectly circular hole around 10 feet in diameter directly through an Earth-sized planet. In ...
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1answer
66 views

I need some formula for raining time --> flood height

I want to make a story in our world, where there is a sudden rain everywhere, and this rain is pretty average but it's permanent. (This is not a raining cycle, because the origin of the rain is ...
-2
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3answers
172 views

What would be the biggest threat if gravity stopped? [closed]

Suppose that the law of gravitation suddenly “stops working” one day, and all gravitational forces cease to exist. What would this mean for people on Earth? Could we survive for very long? If not, ...
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3answers
144 views

How strong is the “explosion” of a bubblegum?

This is for a fantasy/fiction story. I have a character who can manipulate her gum bubbles (so make them strong or bigger, blah blah...), that's why I wanted to know if the explosions of her bubbles ...
7
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1answer
245 views

Fantasy weapon physics - weaponising vacuum

If there is a magical weapon that can 'teleport away' a spherical volume of air/some fluid, basically creating a spherical volume of vacuum in that region, what kind would the resulting implosion be? (...
14
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4answers
1k views

Would pressurized vehicles operating near the surface of Venus float?

So the setting is that we are several hundred years in the future, and scientists are sending humans to the surface of Venus in reinforced vessels similar to submarines or whatnot. We will assume that ...
3
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2answers
178 views

Realistic speedster build

After my initial speedster defense question, I've realized that speedsters are, to put it bluntly, dirty liars. Yes, I knew that the Flash was blurring physics for the sake of a good show, but I didn'...
5
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5answers
174 views

What are some consequences of removing an object’s ability to interact with outside forces?

I have a character with the ability to touch an object and take away its interaction with outside forces such as gravity or pressure. An electric clock for instance would cease functioning because ...
2
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3answers
236 views

Universe without Gravity

Imagine a theoretical parallel universe that does not have and never had a gravitational force. Loose hydrogen atoms would still have formed, and in some cases might have formed H2, but would not ...
16
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7answers
2k views

Shapeshifter problems: Mass conservation

Note I am aware of these previous questions How quickly could a "shapeshifter" lose mass, realistically? Is there a credible way a shapeshifter could gain/lose body mass when changing forms? ...
5
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4answers
258 views

Can active-support ringworlds be built?

The main issue of spin-gravity space habitats is that at some point the centrifugal force will overwhelm the tensile strength of the construction materials, even if perfect graphene were available. ...
5
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2answers
283 views

What would the horizon look like when standing on a very large planet?

Scifi describes the Mars horizon as closer than on Earth since Mars is smaller. On Earth at sea we can watch sailboats gradually drop behind the horizon. The horizon also appears to us quite clearly ...
3
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1answer
281 views

What is the largest asteroid humanity could survive?

An asteroid is hurtling towards Earth with the same trajectory as the one that killed the dinosaurs. Current human civilisation gets one year warning and will do everything it can to secure our ...
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3answers
94 views

Effect of opening up a hyperspace portal on a planet surface? [closed]

Let's say we know how to enter hyperspace. Someone decides it's a good idea to open a "portal" into hyperspace on the planet surface. (I'm assuming this would take a fair amount of energy?) ...
1
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4answers
566 views

What would be possible if my character was able to manipulate electricity [closed]

I am outlining and plotting a novel about someone who is able to manipulate electricity (as in electric currents, charges, etc). Sadly, physics isn't my forte so I was wondering what exactly is ...
18
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9answers
5k views

What is the largest 'hollow' space structure that can be created?

After reading the following question about anti-gravity, I wondered what the largest hollow structure you can make in space is. None of the questions about hollow earth seem to answer this. To put it ...
5
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1answer
107 views

What would happen if someone got stabbed with this taser sword? [closed]

In my world there is a weapon that's basically a magical high voltage, high current sword. It accumulates electricity and when it touches a flesh it instantly discharges, the electricity is supposed ...
9
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2answers
165 views

What Would it take for Trees with Stone Core to be Self Supporting?

So I have an idea for a biome in which avian humanoids are the dominant intelligent lifeform. They live inside of trees that dwarf the redwoods of our world. The trees grow so tall and so thick (akin ...
1
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2answers
98 views

Realistic Top-Speed for a circumplanetary Mass-Driver

Mass drivers for launching cargo or spacecraft can be improved in two ways. Either one increases acceleration (which the wetware can't handle so well) or one increases the length of the mass driver. ...
6
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1answer
258 views

How large and bright has to be a spaceship so that you can see it with the naked eye moving at 0.99c near Pluto?

Today someone looks up at the night sky unintentionally directly towards Pluto. There is a bright light which is impossible to mistake for a star, satellite or shooting star, as it's shaped like a ...
4
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2answers
103 views

Is a particle beam the best method to fire a black hole at a target?

I want to weaponize black holes as projectile attacks in my story from small to supermassive and the two ways i can think of is using mass to attract mass or using matter to push it. Using a particle ...
4
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2answers
261 views

If people were inside the detector of a particle collider during a collision, what would happen to them?

I am aware of the accident when a physicist had a particle beam go through his head, though information on how that happened is scant except for a "safety measure fail". I am trying to build ...

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