Questions tagged [physics]

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

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18 views

planet composition resources (on the physical and chemical composition of the planet)

this is my first world and I want to build in a way that is physically possible (if this is possible, otherwise make the necessary changes) for my civilization (which is mostly fleshed out) but I don'...
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23answers
11k views

What would be best way to re-melt Mars' mantle and core to revive its magnetosphere

Missing magnetosphere on Mars keeps popping up. Most likely caused by Mars core being cold, mantle not bubbly enough. Mars mantle is dormant, core does not move. What would be good way to get it ...
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2answers
109 views

Are Alpha and Beta-Voltaics the solution to the energy storage problem in Scifi?

In Scifi there is often the issue that all the fancy technology like Mechas and Lasguns need a lot of energy. Chemical sources are limited by volumetric and regular power density. Batteries and ...
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2answers
196 views

How does one calculate the diameter of a 'space fountain'?

I need to know how wide the diameter of a space fountain's* particle stream is in relation to the mass it's trying to support. It would have to lift its mass at least 40000 kilometers. The vacuum ...
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3answers
122 views

Popping “vacuum bubbles” loudness

Stun-wizards specialize in blinding and deafening opponents at a distance. To do so, they can exert their magical power to manifest a spherical region of vacuum by essentially "telekinetically" ...
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1answer
118 views

Is an Earth-to-Moon missile technologically possible?

Given current capabilities, is it possible for a missile launched from the surface of the Earth to impact the surface of the Moon? I would imagine the same "rocket" used send stuff to the ISS could ...
8
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1answer
124 views

Air resistance speed limits on a broomstick

I'm working on a tabletop roleplaying game about witches. I have most of the mechanics of broomsticks worked out, but I'm having trouble deciding on top speeds. Speed limits are not a result of how ...
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5answers
208 views

Most energy efficent attacks in a physics-bound magic system

I'm currently working on devising a magic system in which all the standard laws of physics are upheld (Conservation of mass/energy, thermodynamics/entropy, and more). 'Powering' the Spell: To keep ...
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1answer
192 views

What does a global war look like from space?

In the game Mass Effect 3, several planets are invaded by scores upon scores of hostile aliens, who have enough resources to spread their forces over an entire galaxy and still be largely unstoppable. ...
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1answer
96 views

Feasibility of compressing matter to electron degeneracy

So, I have been a bit disappointed with the answers on how to store degenerate matter from my previous thread, and now I'm even wondering whether one can produce it at all, without invoking ...
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3answers
113 views

Constructing a doomsday machine by manipulating the Higgs Field?

I've been working on a sci-fi series set about 1000 years in our future. The discovery of an alien threat leads the ruling government to conceive of a doomsday machine, which they hope will be so ...
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1answer
107 views

Would it be possilble to light the dark side of a tidally locked planet using fiber optics from the right side?

Assume planetary-scale cables are easily constructed, and subsequently ignored. I am assuming these cables would run just under the surface of the planet from one side to the other for minimal ...
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How could superhuman speed and speedsters be made scientifically sound? [closed]

The usual problem I hear about superspeed, is that the human body would be torn apart while running at the speed of sound, regardless of anything else. Also, there really isn’t anything that exists ...
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7answers
1k views

Good explanation for why aliens can't build nuclear engines?

"Aliens used uranium and plutonium to generate energy for thousands of years. However, by the time they got into space exploration, they've used up every last bit of it. That's why they'll have to try ...
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4answers
236 views

Will we need to replace conventional rockets to send manned missions further into space?

Currently, chemical rockets have taken men to Earth orbit and the moon by combusting rocket fuel to generate thrust. Even if we develop more efficient rocket fuels and can create significantly ...
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13answers
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Is it possible to make sharp wind that can cut stuff from afar?

You know the typical wind slash in anime or games where the swordsman slashes from afar either vertically or horizontally and the wind pressure or projectile cut the opponent, like in this image for ...
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5answers
252 views

What improvements in the human body will allow it to withstand critically low or high pressure?

My question: What is it that needs to be improved or added to the human body so that it can withstand critically (fatally) low and high (if, my genetically modified person is underwater or a very ...
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1answer
637 views

Is this a plausible interstellar propulsion system?

Interstellar travel is hard and complicated, yet I want to have a plausible interstellar propulsion system for my setting. Rockets are out because of the rocket equation and the horrible top speeds ...
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10answers
10k views

How many pillows would you need to survive a fall from a church tower?

The praised Dutch book "Koning van Katoren" features an 18 year old who wants to become king of his country of Katoren, which had been under the regency of half a dozen evil ministers for his whole ...
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5answers
938 views

In regards to heat managment on a starship + space combat

Various sources consider heat emission and heat management a major issue when it comes to setting up "realistic" space battle scenarios. I have a few questions in regards to this: Heat is a ...
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2answers
134 views

Could a vehicle levitate through use of ultrasonic sound waves?

This is a bit of a continuation of my previous question, could a form of acoustic levitation be used as artificial gravity? In that question, I referenced how some scientists use acoustic levitation ...
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10answers
2k views

How could two alternate realities “blend” at a single point in space time?

From: https://en.wikipedia.org/wiki/Multiverse The multiverse (or meta-universe) is a hypothetical set of various possible universes including the universe which we live in. Together, these ...
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4answers
211 views

Skysteading: How to build a flying city

I am building a city in the sky; it floats thanks to hot air balloons and hydrogen. The main issue I have is how to make it grow, as this is not some kind of giant structure to start, it is a small(...
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3answers
127 views

How to tell it is a relativistic kugelblitz instead of other photonic attack?

Set in a quite distant future, intergalactic war is brewing and it is important to tell what form of attacks the enemy ship is using otherwise the battle will quickly become one sided. Anyway imagine ...
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2answers
68 views

I heard that water is a medium for heat exchange how would a water manipulator use vapor to control air via temperature?

From the superpower wiki I heard that vapor is a medium for heat exchange, but when I did some research on it I found that heat exchange might need a closed system. In a fictional world how would a ...
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3answers
307 views

How large can a flying insect get and still be able to walk upside down?

Given the perfect environment, denser atmosphere, oxygen rich, maybe lower gravity, how large can a flying insect get and still be able to walk upside down on a surface? This question starts to ...
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3answers
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How could a medieval melee weapon slice through ankylosaurus?

Set in the early 14th century A. D. the sudden appearance of dinosaurs wrecked havoc on the world, no one know why but everybody raced to come up with powerful theories except for a particular group ...
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5answers
462 views

If the Earth is not flat, can walking on it be described as uphill or downhill? [closed]

If the world isn't flat and a person is walking around it from east to west. Is he walking downhill or uphill ? (This a stupid question on many levels, but I'm looking for intelligent answers.)
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2answers
229 views

How plausible does the power source for this fictional giant robot sound?

Here is a big one for you engineering fans to chew on. First off, a little context: The giant robot in question is called Mazinger Z, considered to be fiction's first pilotable mecha, launching the ...
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1answer
75 views

Densest practical packing of protons vs. neutrons?

For background: I have some sci-fi technology based on sci-fi physics which depends on some fictional forces that interact differently with up quarks vs. down quarks. So, to get certain types of ...
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2answers
141 views

Lagrange systems: What is the mass range for a gas giant if I want to place a earth-like planet on L4 and L5

I am wanting to make a 3 world lagrange system around a Sol analog star that includes 1 gas giant and 2 terrestrial worlds with large moons. I want the terrestrial worlds to have a similar gravity to ...
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2answers
288 views

What would powers based of the strong force look like?

Or, what physical law can X manipulate in order to have control over the strong force. The strong nuclear force is responsible for binding the all matter together and opposes the force exerted by the ...
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5answers
232 views

Why would a human bomb not be blown apart by rune magic?

I am a homicide detective on the magical police force. Runes are magical symbols fused into objects that imbue those items with magical power. These spells are stored in these runes for long term use ...
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1answer
503 views

Plausibility of helium dominated atmospheres on super-Earths

I've been using this helpful diagram a lot for worldbuilding. Now I came to think about the fact that helium is more massive than hydrogen, thus a scenario where hydrogen escapes, but helium is ...
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7answers
3k views

How do ballistic trajectories work in a rotating cylinder world?

For the sake of fixing some image in your mind, imagine you want to practice some sport in a rotating cylinder world: whether it be launching a javelin, strike a tee at the golf club or scoring a 3 ...
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0answers
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How soon can the first stars form?

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 ...
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1answer
74 views

How can a being that can create electric attacks use targeted lightning storm strikes?

I found one question that deals with how to make lightning from clouds strike a target person, Can we make lightning strike a certain person? but I am looking for something that doesn't involve ...
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5answers
652 views

Need method to eliminate all life on planet [duplicate]

Space faring advanced species needs to 'disinfect' planets in habitual zones around stars. That's all life. They can wait a few thousand years to come back and seed the planet with a new ecosystem. ...
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2answers
137 views

Maximum Theoretical Energy Density of Clockwork

So, I'm slowly working on a concept a little like "Victorian Shadowrun", where magic is suddenly introduced to Victorian Society. One of the side effects of this is a metal, let's call it Orichalcum ...
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5answers
8k views

Can two moons have intersecting orbits yet be guaranteed not to collide?

Working on a D&D campaign. As a physics nerd, I'd like the orbital mechanics of the planet, its sun, and its moons, to follow standard Newtonian/Keplerian mechanics. I'm trying to come up with ...
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1answer
136 views

How would life evolve in a universe with constant atmosphere? [closed]

For a type of multiverse, where physics are the nearly same as ours, but space has a constant atmosphere comparable to our Earth's. How and where would life evolve, if it can? what I mean is that the ...
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49 views

A place for telekinesis in physics? [duplicate]

I am a writer, and I have attempting my first fiction novel. However, I like to have things figured out in a way that works with the laws of physics in the universe, at least to a certain regard. For ...
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4answers
310 views

What would powers based on electromagnetism look like?

Or more specifically, What physical law can X manipulate in order to affect the electromagnetic force? For something to base our assumptions off of, lets assume that we can; Fly Cast lightning ...
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2answers
208 views

What would powers based on the weak force look like

In other words, What physical law can X manipulate in order to control the weak force? And as for the abilities, I...don't have the greatest grasp of what someone can do with the weak force as their ...
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1answer
89 views

Can a planet's artificial ring always face the sun?

A habitat/space harbor ring encircles an ice giant crossing both poles (polar orbit) and rotating to create artificial gravity. Can the ring also precess in synchronization with the planet's year, so ...
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2answers
208 views

do these mountains look to be in realistic locations?

I'm getting into mapmaking, which I enjoy, but some of the specifics of realism still elude me. I know generally how plate tectonics work, but I was hoping to get some help on a specific example. I ...
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1answer
113 views

Concerning magic and the replacement of the four traditional elemants with the four fundamental forces [closed]

In a world of magic where spells are not based on fire, water, air, and earth; rather, the electromagnetic force, the gravitational force, the strong nuclear force, and the weak nuclear force—How do ...
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5answers
464 views

The effect of a 20 kilojoule punch on a person that is wearing a plate armor

I have always been in love of hand to hand combat but I realize the concept of efficiency and why that is not an ideal choice for combat so I decided to write a story in which characters who are ...
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1answer
195 views

How big could a planet get before collapsing due to its own gravity? [closed]

I was wondering, how big could a planet get, with gravity staying the same even with the added mass, before collapsing DUE TO its gravity?(without becoming a black hole) Specifically, I have a world ...
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4answers
329 views

Cheapest material per ton on earth?

What is the cheapest material per ton that one could purchase on our Earth in the 21st century? This could also include the cheapest material per ton to harvest so dirt may seem like the obvious ...