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Questions tagged [reality-check]

Asks if a given concept is realistic in a given context. Answers should say yes or no, with supporting info. Compare this with the science-based and hard-science tags. This tag should never be the only tag on a question, because this tag frames how a question should be answered, not the topic.

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2answers
2k views

How would nanobots consume objects?

I've been thinking about a cyberpunk universe where nanobots are a universal force capable of achieving many things, examples include: Biological and medical modifications of the human body Construct/...
30
votes
5answers
4k views

Dietary Requirements of Giant Spiders

Giant Spiders are a traditional element of fantasy worlds. They prey upon most human's primal fears, and are easy to make as evil as possible. (Note: Not to scale) But are they actually plausible? ...
9
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2answers
898 views

Seasons on a planet that's tidally locked with the smaller star in a dual-star system

Consider a dual-star system, with the distances between S (larger star) and J (smaller star) similar to Sun–Jupiter. A planet P rotates around J on a 90-degree ecliptic and is Earth-like otherwise. ...
21
votes
9answers
2k views

Cataclysmic event resulting in a region of glass?

I have in my world a "crystalline desert". The idea is that a major cataclysmic event turned the surrounding area into glass, color irrelevant. Then following the event, major earthquakes and the ...
5
votes
5answers
669 views

Background for hi-tech in low tech

For some time, I have been playing around with the idea of a medieval-like world, but with the twist: Some sci-fi tools exist and are fully operational. But I cannot come up with good and plausible ...
15
votes
6answers
3k views

Planet with dual core

My premise involves a habitable planet with a dual core: it has two masses similar in composition to Earth's core, which revolve around each other over the course of hundreds of thousands of years. ...
37
votes
14answers
8k views

Can I keep our universe, but without the speed limit (of light)?

It seems like nothing can move faster than light and this is quite bothersome for interstellar travel. It takes decades in the best case to get anywhere interesting in our little Milkyway (Many ...
21
votes
12answers
8k views

If a space ship crashes on a planet, is it realistic that things from that space ship could be rescued afterwards?

The situation I'm considering is as follows: A space ship (a transport ship operated by two people) crashes onto a planet on which a swing-by was planned. The crew could escape using an escape ...
2
votes
2answers
887 views

How would tectonics behave on a two continent planet?

I am working on constructing a world which is basically (from the northern pole to the southern pole): smallish frozen over ocean huge land mass encompassing the northern hemisphere tremendous ocean ...
11
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5answers
1k views

Could higher land-based life exist on a planet with a pressure of about 1 MPa?

This is somewhat of a follow-up question to my ammonia-based world question. I've found out that the melting point of ammonia is at 25°C at a pressure of about 1 MPa (about 10 times the atmospheric ...
27
votes
8answers
4k views

Building the Death Star with today's tech

I found an interesting Wikipedia article, quoted in an answer here. I'm looking into writing a story where someone has built a Death Star. The purpose of this craft is important to the story (and the ...
8
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3answers
2k views

Could a government control its people using frequencies?

Setting: Earth, in the future, near 2060 or 2100 Technology: a bit more advanced than ours Armies and police forces are already using systems for crowd control. Some devices can generate discomfort ...
32
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8answers
5k views

Can we 'beam' energy from the moon?

Really can't believe I have to edit this in, but this question has no bearing on our current use and generation of nuclear energy on Earth. There are dangers to nuclear energy generation, or we would ...
10
votes
2answers
3k views

Can anything survive by eating rocks and other ground minerals?

Are there bacteria or other types of lifeforms that feed on rocks and other ground minerals? And if there aren't, is it technically possible? It can eat other things but the majority of its diet ...
4
votes
4answers
411 views

Could life survive on a diet of dust?

Could life survive on a diet of dust or some other substance that is both abundant and that we don't place any value on?
5
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6answers
9k views

Can a genetically modified human breathe something other than Earth's oxygen/nitrogen atmosphere?

If a human is kidnapped by an alien vessel and taken to another planet - and, for the sake of argument, let's assume that the alien life-form lives in a completely different environment than Earth's. ...
5
votes
1answer
857 views

How big is a big city?

According to two RPG systems; Dungeon & dragon and Pathfinder; a metropolis is the largest category for medieval city. The population of a metropolis starts at 25 000 people. I remember that they ...
33
votes
9answers
5k views

Could a technological society develop without agriculture?

Before the advent of agriculture, humans fed themselves by hunting and gathering. Hunter-gatherer societies tend to function quite differently from agricultural societies. Arguably, historically, ...
17
votes
2answers
4k views

Is metal-based, or other non-carbon-based, life realistic?

One science fiction short story I read (I don't remember the title or author, sorry!) featured some small creatures (unnamed) that were formed from metal, with the argument that "just like life ...
14
votes
5answers
2k views

Asteroid impact. How big does it have to be to globally affect plate tectonics?

I want to know about the plausibility and required parameters of the following scenario: Take an Earth-like planet, about the same size, composition and gravity. It has no plate tectonics to speak of....
22
votes
16answers
2k views

Scientifically Plausible Reincarnation?

Is it scientifically plausible for reincarnation to exist? When I think of reincarnation I am thinking of the following: Memories, personality, biases, opinions and feelings carry over from one life ...
27
votes
5answers
5k views

Can a planet have a figure-8 type of orbit around two separate stars?

Could a planet have an orbit in the shape of a figure 8 around twin (possibly binary) stars? Mostly curious about the physical possibility of such an orbital arrangement; is it stable over a long ...
6
votes
4answers
673 views

Scientific Accuracy - alien communication ideas

(Disclaimer: I tried this question earlier in the scifi site as well as real science sites, and was told should be on topic here) I'm writing a speculative story about aliens coming to earth - and ...
35
votes
5answers
6k views

Can a planet realistically have multiple suns?

Several science fiction books I have read (including, IINM, Nightfall by Asimov) have featured planets with several suns. Some worlds where this happened wrought interesting effects on the inhabitants ...
21
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6answers
3k views

Living Planet Possible?

Although a question about how large a living thing could be has been asked and answered, would a being such as Mogo from DC's Green Lantern series be possible? Mogo is the size of Earth roughly can ...
4
votes
3answers
709 views

Generating a magnetic field for planets with iron-cores that is revertable?

I'm looking for a solution to generate a strong enough magnetic field for planets with iron-cores - in my case, Mars - to keep the atmosphere from getting blow away by the solar winds (and ignoring ...
12
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6answers
1k views

What would be the communication range of an underwater species?

It's a commonly known fact that whale song travels huge distances. In fact apparently before the oceans were so noisy they could communicate over 10,000km! However, whales are very big! They can ...
42
votes
5answers
5k views

Could a humanesque creature derive all its nutrients from drinking blood?

Vampires are a very common creature in various fantasy stories, they drink blood and often human food poisons them. Forgetting for the time being the additional rumours/fiction such as sunlight, ...
38
votes
10answers
5k views

Could a technological society develop without wood?

Imagine a world things evolved slightly different: plants never evolved into trees. There are bushes, herbs, mosses, etc, but no trees. Thus no wood to make planks, nor for building. Given abundant ...
25
votes
7answers
5k views

Could life form in outer space?

All life we know of to date (presumably) formed on a rocky planet (more precisely: earth). Fiction has been written about life in more exotic locations. Though as far as I know, these lifeforms were ...
27
votes
9answers
8k views

How big could a living thing be?

Simply put is there an upper bound for the largest possible living creature in a scientifically rational world without incorporating anti-gravity, magic, the force, or other physical concepts we are ...
41
votes
6answers
5k views

How do I prevent my turtle from collapsing under its own gravity?

Suppose the universe contained a species of planet sized turtles1 that can travers at least interstellar space. How can I explain (without invoking magic) that these turtles are not spherical? If ...
25
votes
5answers
5k views

Humans born without legs: how would they thrive?

or, Anatomically Correct Weebles A group of behaviorally modern humans was cut off from the rest of the earth-like planet millennia ago. (Myths hold that the separation occurred four to five ka BP, ...
6
votes
1answer
235 views

Biology of humanlike species within Buddhist and Judeo-Christian Realms [closed]

I have a world that I largely have figured out in a big picture sort of way. It's sort of a Buddhist realms style "multiverse" with multiple realms encompassing the true universe. In this multiverse ...
35
votes
13answers
7k views

Can a river be put under enough pressure to jet straight up for a mile?

I've been mulling over an idea for my preferred RPG setting, and I wanted to check if anyone knows the following: Is it possible for a river to flow underground for miles, and then suddenly be put ...
35
votes
5answers
30k views

Is it possible to genetically modify a being after birth?

In many stories we hear about people whose genetic structure is modified after they're born (Spider-man, The Fantastic 4 and practically any other superhero you care to mention). However current ...
13
votes
7answers
2k views

What is the likelihood that inhabitants of an alien planet similar to Earth geologically would have races?

First off, let's get definitions out of the way: A "race" here is defined as stable, heritable, phenotypic, clearly visual distinction between large demographic groups living in different geographic ...
6
votes
7answers
1k views

How could a force field dome be realized in my city?

In relation to this question, how could I create a force field dome over that city? Specifications of the city: 10 x 40 km on the surface 1 km in height has a city wall of 100 m all around the edge....
19
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3answers
9k views

What is the likely method of surviving a Tsunami in a city?

After asking this question, What's the worst natural disaster that could hit New York City in our lifetime, it looks like the most popular answer was a Tsunami. A tsunami, however, from the sources of ...
6
votes
3answers
1k views

What light gas can I have in the upper atmosphere?

I want to have an upper atmosphere composed of a gas which is lighter than "air" so that my human occupants of a planet can harvest it and use it to fill blimps and hot air balloons. I'm planning on ...
14
votes
4answers
1k views

Can whiteout/snowstorm conditions be coupled with heavy fog?

In a story I am working on, I need a scene in which one of the main characters finds himself outside in precarious weather conditions, unable to see unaided much farther out than an armlength or so. ...
54
votes
11answers
15k views

Is a man-eating plant realistic?

Carnivorous plants live in nutrient-poor, highly lit habitats, such as bogs or rocks. For example Earth's biggest carnivorous plant, Nepenthes rajah, lives on mountain-tops with high concentration of ...
9
votes
5answers
3k views

Why would a complete urbanized city-planet exist?

Related: How would a completely urbanized city-planet support its population? How a completely urbanized city-planet be maintained? How would the global environment of a completely urbanized city-...
14
votes
3answers
3k views

What would be the minimum distance between front line trenches in trench warfare?

How close could two trenches be in a stationary war that lasted about 4 months? Specification: Infrastructure should be established and there is artillery in use. The no man's land is mostly plain ...
24
votes
5answers
2k views

Feasibility of anti-matter as a fuel

Now, taking out the cost to produce/collect it, assume somehow we perfected a formula or find a natural source (because that is currently very prohibitive), how feasible would be to use antimatter as ...
0
votes
0answers
76 views

Scientific Accuracy - alien communication ideas [duplicate]

I'm writing a speculative story about aliens coming to earth, and just wanted to bounce a couple of ideas for scientific accuracy (or at least lack of obvious impossibility). This is set in the near ...
45
votes
15answers
4k views

What are the primary triggers for the decline and fall of great empires?

Let's focus specifically on the devolution of empires. How is it that something so powerful falls? The collapse of Rome, Byzantium, the Han, the Mayans and so on. What similarities can be seen in ...
20
votes
4answers
1k views

City in a hollow tree

As a tree grows new layers are added each year so that the trunk expands in radius. The living part of the tree is a relatively thin layer on the outside just beneath the bark, and the wood further ...
62
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5answers
3k views

Are geographically typed planets realistic?

In many science fictions we see planets which are designated by a particular terrain type. For example, Dagobah is a swamp planet, Tatooine is a desert planet, and Kamino is an ocean world. However, ...