Questions tagged [physics]

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

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13 votes
9 answers
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How could people survive teleporting into the atmosphere while surrounded by vacuum?

In my planned fantasy story, the protagonists must escape a dangerous situation by teleporting the ship they're on (a kind of steam-powered ocean liner) into outer space, then back to the ocean ...
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  • 131
4 votes
2 answers
123 views

What are the effects of Increasing the gravity on Mars?

I'm interested in the Physics around increasing the gravity of Mars to make it habitable. I was unsure how to work out what gravity would be needed to retain an atmosphere thick enough to hold liquid ...
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3 votes
1 answer
54 views

How to place multiple small moons and one large moon in stable orbit around an earthlike planet?

Earth has one very large, spherical moon believed to have been formed by a giant impact. Mars has two small, sorta potato-ical moons believed to have been captured. Suppose an otherwise earthlike ...
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  • 803
7 votes
4 answers
1k views

Can Mars disintegrate entirely in this scenario?

I have a hypothetical scenario in which Mars flies over Jupiter at close range. I want to make Mars disintegrate entirely in this scenario while keeping the scenario scientifically accurate (please ...
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6 votes
2 answers
183 views

Using coilguns or VASIMR as thrusters in a game

i'm in the early stages of designing a scifi game and want to use as little handwavium as possible (without ruining the fun). The first part of the game takes place in the asteroid belt and includes ...
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  • 69
6 votes
1 answer
145 views

How would the laws of physics need to be adjusted if there really were a preferred frame of reference for FTL?

I am considering how to implement faster-than-light (FTL) travel in a sci-fi setting without the attendant problems with causality. One of the ways I've been thinking about for this is establishing a ...
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  • 553
1 vote
1 answer
121 views

Can kinetic energy be converted into cooling?

In a hypothetical scenario, I'm trying to design an object where, the faster it moves, the more it cools something it comes into contact with it. There's all kinds of materials that can convert energy ...
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6 votes
2 answers
233 views

Can you survive a reduction of particle mass?

Inspired by reading some recent questions about going to space and torchships and such, I've come to the sad conclusion that space is hard and rocket equations suck. So what if we made advances in a ...
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  • 1,504
-1 votes
4 answers
148 views

How could I calculate the necessary power to kill a fictional beast?

Say we have a pterodactyl-wyvern or a huge dragon-anaconda, maybe something like a t-rex, or a sand-crocodile, or a slime--- you get the idea. Assuming one wanted to make a fictional manual with ...
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  • 425
4 votes
2 answers
110 views

For a planet with a given equilibrium temperature, what is the maximum pressure possible?

I've been working on trying to calculate atmospheres for a given equilibrium temperature $T_{eq}$ planetary mass $M_{planet}$ and radius $r_{planet}$, how would you calculate the maximum possible ...
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  • 101
39 votes
10 answers
7k views

Can a planet stay cracked?

Images like this and this are common in sci-fi/fantasy settings, for the obvious "rule-of-cool" reasons. And while the 'rule-of-cool' is certainly worth using (in moderation) when ...
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  • 4,005
7 votes
3 answers
173 views

Ballistic properties of unobtainium

A Banks Orbital requires some form of unobtainium, with tensile strength much greater than any known substance. I'm trying to figure out how that substance would stand up to impacts and explosions. To ...
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  • 4,398
5 votes
3 answers
90 views

Moving Ceres to a new home?

Is it possible to use Ceres is a generational garden ship? The idea would be to tunnel out a Stanford torus like set-up under the regolith in the ice layer around the equator: underground but ...
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4 votes
1 answer
102 views

How does the time to die from venom change for very large organisms?

Let's say that an untreated snakebite kills a human in 2-3 days. Now consider a much larger mammal, such as a blue whale. If a proportional amount (equal chance of lethality) of the same venom was ...
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  • 3,187
5 votes
4 answers
1k views

How can a mechanical clock be powered by wind in a reliable, constant way?

Picking up the context This is a follow-up question to the technologically accurate watermill clock, available here. In this case, we're not using water to make clocks, but wind! Wind will be the ...
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  • 4,399
2 votes
1 answer
162 views

Can useful second and third generation matter be synthesized?

The standard model predicts that beyond the normal matter made from up and down quarks and electrons the exist two other kinds of matter. Second generation matter is made from strange and charm quarks ...
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5 votes
5 answers
175 views

How different would water need to be for boats to be impossible?

I mean changing the actual physics behind water (density, and other properties). How different would water need to be, to result in ships being impossible to build? (i.e. the ability to create ...
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  • 51
13 votes
14 answers
2k views

How can this teleporter escape from eternal falling?

Let's say we have a teleporter, whose teleports obey conservation of momentum. I.e. if they are moving, and they teleport, then they will continue moving in the same direction. The have no hard range ...
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9 votes
3 answers
2k views

How much would the ground shake under King Kong?

I needed a creature about 50 feet tall and King Kong from the 1976 movies fits the bill. According to sources he is 50 feet tall and weighs 7 tons (I raise a large eyebrow at that, but it is all I got)...
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7 votes
3 answers
348 views

Natural structural formation of matter

In nature we see natural pattern formations when a material forms an organised structure within a less dense material in order to fill the space in the most efficient form. Such as hexagonal and ...
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13 votes
7 answers
3k views

Could cybernetic spinal cord implants grant superhuman strength?

In the 2018 movie Upgrade, the quadriplegic protagonist gets a cybernetic neck implant that reconnects his spine and returns his control of his limbs. However, this implant also appears to give him ...
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5 votes
3 answers
149 views

How would future galactic civilizations deal with the Big Rip? Could they escape it or hide anywhere, like inside black holes? [closed]

Humans colonized all the stars in the Milky Way in the first million years. In the next 200 million years they conquered all the planets in the Local Group. In the next few billion they conquered all ...
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  • 111
0 votes
1 answer
131 views

A solution of P=NP breaks quantum ciphers [closed]

Somebody finds an effective NP-complete algorithm. Then he breaks quantum ciphers by reversing time (time can be made backward by quantum symmetries, so the difference between forward and backward is ...
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  • 125
6 votes
1 answer
126 views

How much payload can a space elevator support?

I'm working on a project involving an interstellar society, and I'm looking to incorporate as much actual science and economics into the project itself since I'm a stickler for numbers and logistics. ...
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6 votes
2 answers
350 views

Atmospheric pressure in an almost empty world with a specific habitable zone far above the ground

I'm currently working on the following concept of a world for a high fantasy setting: The world's core has a radius of around 100 km. Inside is a magical object that creates a large-scale (planet-...
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4 votes
4 answers
181 views

How can I make a technologically correct horizontal watermill clock?

Context As I was working on some mechanical ideas (and practicing art), I wanted to see how to render time in creative ways. So I decided to make an horizontal watermill akin to a turbine, which has ...
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  • 4,399
4 votes
2 answers
161 views

Could manipulating the strength of the nuclear force disintegrate materials?

In my world, magic works by warping the fundamental forces of the universe. Some people can heat metal and create lightning with the electromagnetic force. Others can steer and amplify gravity to ...
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3 votes
1 answer
88 views

What would realistic racing hovercraft look like in terms of aerodynamics?

This is a follow up to a previous question of mine: How do I keep my futuristic racing hovercraft from becoming airplanes? I'm in planning stages for a futuristic racing game and I'm trying to figure ...
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  • 2,776
0 votes
1 answer
116 views

On the best arch types for underground cities [closed]

I am working on a civilization that often digs into mountains, and I am wondering what form of arch would work best to hold up all the mass from the mountain above the halls. I know many arch types ...
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  • 734
3 votes
1 answer
112 views

What kind of atmospheric composition would make the sky look green and still be breathable?

In my story scientists discovered a planet that look green from the telescope and they used a advanced starship to go there and the y found out that the planet is habitable with a breathable ...
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4 votes
2 answers
244 views

What would happen if a neutron star approached the solar system?

Given its enormous eletromagnetic field and gravity( and probably gravitational waves would be very powerful) what would happen if a neutron star approached Earth? What if approached just by few light ...
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4 votes
3 answers
145 views

Simulation theory experimental proof

A lone researcher elegantly solves an unsolved physics problem with a brilliant proof and proposal for a reasonably inexpensive experiment to go along with it--however this proof only works if it's ...
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5 votes
2 answers
79 views

Feasibility of multiple satellites around a planet inspired by Luyten B/Gliese 273b

I am writing a science fantasy book that takes place on the planet Luyt (inspired by Luyten B/Gliese 273b). Because the orbital period of the planet is about 18.6 days and I have chosen to make the ...
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1 vote
1 answer
108 views

Could this world use a buoyant ballistic weapon?

I don't know if there is a word for a ballistic projectile with buoyancy, but feedback from the weapons in my dense atmosphere suggests that I should consider changing the shape of my projectile, and ...
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  • 5,894
7 votes
2 answers
800 views

Negative mass and Dark matter in Alcubierre Drive?

I am writing a science fiction novel therefore I am using the idea of the Alcubierre drive for warp travel which involves some handwavium but has roots in theoretical physics (which is my goal). While ...
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  • 159
5 votes
2 answers
151 views

Maximum effective range for a modified Long Tom cannon in high density?

My airships in combat come upon each-other and initiate combat with their 12-foot long-tom guns. My problem is, I don't know what range they would be at when they decide to fire, because the post-...
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  • 5,894
4 votes
4 answers
215 views

Airship combat in dense atmosphere - What charge for 26-lb cannons?

For an airship combat scene with cannons on a world with a dense atmosphere, what would be the powder charge for effective beam-to-beam attacks at a 100-yard range? The projectiles are 26-lb cannon ...
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  • 5,894
5 votes
2 answers
124 views

Is there a metric for how far underground a nuclear bomb needs to be to safely be tested?

I'm running a one-shot cold war campaign where the PCs are going to sabotage a prototype Soviet giga-ton bomb. Realistically, how far underground would a giga-ton bomb have to be buried to be safely ...
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4 votes
5 answers
283 views

When is the earliest possible opportunity for earth to create an absolute unit of measure?

Throughout history we have used units of measure that were defined by arbitrary standards; things that were conveniently around when whichever government needed something measured. “How much tax does ...
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  • 5,894
2 votes
3 answers
105 views

What would the typical damage of a person creating propulsion on themselves and then use that momentum to punch someone be?

Lets say a character can create magic propulsion to push themselves, fly, and move quickly. And then this character uses this speed and momentum to punch someone. At what speed would the user begin to ...
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1 vote
2 answers
120 views

Gravity assisted travel along a Cosmic string

VSL (variable speed of light) cosmologists have theorised that Cosmic strings could be used as FTL highways for information. This is based on the theory that the speed of light was infinite at the ...
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4 votes
2 answers
209 views

Unforeseen Consequences of Limiting Nuclear Fission

From my understanding nuclear fission takes place in two different scenarios and correlates with the speed of a neutron. In terms of material, we have fissionable material which undergo nuclear ...
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  • 885
2 votes
4 answers
589 views

What happens to an individual atom in an antimatter reaction? [closed]

So the answers to this question I asked about an antimatter accident got me thinking about the particulars of interactions better atoms and subatomic antimatter. I'm assuming an antiproton would ...
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  • 44.3k
4 votes
7 answers
261 views

Creatures which can be mortal in one dimension and immortal in another dimension, How do I avoid time freezing forever?

These beings can live a normal life, except they switch dimensions, their body still remains in the same place. But almost as if time froze, they are transported in another world, an infinite ...
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  • 1,732
11 votes
5 answers
462 views

What would the sky look like on an infinite plane?

The world is an infinite plane with an Earth-like surface. It has an atmosphere, but it has finite height Because of this, and how fields work, this should give us the same gravity all the way up, ...
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  • 11.8k
6 votes
4 answers
220 views

Feasibility of active defense systems against kinetic weapons

Spurred on from an earlier post over here. The general consensus was that if a depleted uranium round is coming your way, don't be in its way. And if you do get hit, disperse the damage as much as ...
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  • 885
6 votes
4 answers
1k views

Intercepting/surviving tank based high velocity kinetic weapons

Suppose in the future tanks are able mount higher velocity guns such as railguns or electro chemical technology (ETC) guns. Suppose these tanks slightly larger normal (no you can't mount a railgun on ...
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  • 885
9 votes
7 answers
1k views

How would a chronologically accelerated/slowed object affect a chronologically normal object?

The world has a kind of magic called chronomancy, essentially time manipulation. It can be done on two scales: local and universal. Due to how the cost of magic works even the most experienced or ...
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  • 4,417
4 votes
2 answers
180 views

How long can this planet hold its atmosphere?

Humans are looking for a permanent home. They colonized Mars and later terraformed it, temporarily, before being forced out of the solar system entirely when the Sun went all Red-Giant on them a few ...
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  • 4,005
2 votes
1 answer
135 views

What material do I use to make a biological electromagnet?

This is rather simple: I want a biological electromagnet capable of producing a weak magnetic pulse when electrified. I recognize what an electromagnet is: a coil, spiral, or helix of conductive ...
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