Questions tagged [science-based]

For questions that require plausible (better than suspension-of-disbelief) answers based on Real World science that are not necessarily constrained to the known limits of Real World science. Contrast with the hard-science, science-fiction and internal-consistency tags. This tag may not be used alone. This tag may not be used with the science-fiction, hard-science, or internal-consistency tags.

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77 votes
17 answers
20k views

How can I move a planet?

There are a lot of answers on Worldbuilding about how to destroy planets - just as an example - and they seem to be the method of choice for many people intent on destroying the world. My objection to ...
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81 votes
11 answers
76k views

How many people can you feed per square-kilometer of farmland?

Questions about how to feed a large population keep popping up on this website quite frequently. One obvious option is farming. But how many people can you feed per square-kilometer of farmland? ...
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67 votes
9 answers
10k views

Are there any ways to allow some form of FTL travel without allowing time travel?

Faster than light travel is a really cool thing to have in sci-fi settings. It allows humans, in relatable time scales, to travel the galaxy and see a variety of worlds. It allows for conflicts ...
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194 votes
18 answers
80k views

How could dragons be explained without magic?

Dragons are a grand classic of fantasy. For this question, let's assume we're talking about the following stereotype: hatches from an ostrich-sized egg and can grow to mountain size if nothing limits ...
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74 votes
4 answers
9k views

Can you simply scale up animals?

There have been a number of questions focusing on mythical creatures where the logical approach to answering has been to scale up an existing animal. For example dragon's wings can be extrapolated ...
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79 votes
28 answers
10k views

The opposite to Worldbuilding: World Destruction

I am looking at different ways to destroy a planet. I am assuming the planet is of a similar size and composition to the Earth just to keep things simple. I am starting at boiling the atmosphere to ...
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52 votes
2 answers
15k views

How would winds behave on a tidally locked planet?

If an earth-sized planet were tidally locked to a star, and was in the life zone of its star with an earth-like atmosphere, what would its wind patterns be like? The planet would have one hot ...
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42 votes
7 answers
13k views

Hard Sci-fi energy shields

I'm making a fairly hard Sci-Fi story, and I was wondering what the most scientifically plausible 'energy shield' (for ships and stations) would be. My world tries to remain true to basic physics, but ...
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64 votes
6 answers
21k views

Other blood colors

Many people know that our blood is red because it is iron based. Many people also know that blood is blue or green if it is copper based. I'm wondering what color blood would be if it was let's say ...
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60 votes
6 answers
12k views

How far away would an alien civilization need to be for us to not notice them?

Far away, across the vastness of space, lies an alien civilization, who are pretty similar to us. They've got ice cream, peer to peer networking, and photography. More importantly, they do lots of ...
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47 votes
7 answers
11k views

How powerful of a computer do I need to simulate and emulate a human brain?

The title is pretty self-explanatory. How powerful does a computer have to be before it has the hardware capability to simulate and emulate a human mind in real-time? I'm leaving the question of the ...
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38 votes
4 answers
11k views

How to make a realistic 'giant'

Imagine a race of what we would call 'giants', each of them possibly around 8 to 10 feet (2.40-3.00 meters) tall. What differences would they need compared to us regular humans in order to function? I ...
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25 votes
7 answers
5k views

What are some plausible super materials? [closed]

Background Science fiction is rife with "super materials". Most often the materials are made from elements unknown to Current Era (CE) science. They use names that make us think of elements without ...
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58 votes
3 answers
27k views

Creating a realistic world map - Currents, Precipitation and Climate

This Query is part of the Worldbuilding Resources Article. Once geological processes and erosion have created a landscape this landscape will in turn alter the planet. Ocean currents and trade winds ...
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23 votes
3 answers
10k views

What is the maximum size of a flying creature?

Giant winged beasts such as the Roc and the western dragon feature strongly in mythology. Is there a maximum size on a biological winged flying creature? How would an atmosphere different from Earth'...
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99 votes
14 answers
11k views

Is there a scientific explanation as to why aliens should look similar to us?

In almost all science-fiction stories that include alien races, said aliens are similar to humans in many ways: bipedal (and often humanoid), communicate with sounds coming out of a mouth, orient in ...
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57 votes
3 answers
18k views

Is there a maximum size an ocean bound creature could grow to?

Assuming the ocean is deep enough and not overcrowded is there any upper limits to the size a "sea monster" can grow? On land creatures are limited by gravity, they have to be able to generate the ...
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47 votes
23 answers
13k 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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64 votes
29 answers
16k views

How would humanity enter a Dark Age?

Humans have grown fat, complacent and cock-sure of the certainty of future progress, arrogantly expecting to build minds in their own image. They even dream of building themselves a city, with a tower ...
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46 votes
5 answers
7k views

How do seasons work in a binary system (planet orbits one star, not both)?

I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a double day; when the primary sun sets the secondary one rises, no overlap. ...
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36 votes
5 answers
2k views

How to evolve biological radios?

Radio Thinkers Creatures that communicate by biological radio pops up in science fiction occasionally and it's a fun idea. However, there are some practical concerns with regards to evolving a radio ...
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44 votes
10 answers
65k views

How many people are required for a healthy re-population of the Earth (Post-Apocalypse)?

In my particular Earth, much has remained after the human-killing virus, and nature is thriving - even taking over the cities. It's beautiful. But I have separated the healthy populace in orbit ...
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  • 17.3k
35 votes
6 answers
6k views

What's the smallest reasonable natural planet or moon with Earth-like surface gravity?

We all know that equation for surface gravity is $$ g = \frac{4\pi}{3} G \rho r $$ So if we want Earth-like surface gravity of $ g = 9.81 $, then the equation for radius is $$ r = \frac{3 g}{4\pi G ...
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81 votes
21 answers
8k views

Is it physically possible for a planet to have seasons of different lengths?

Those of you who have read Game Of Thrones will know that in the GOT world seasons do not have a fixed duration, e.g., a winter might last three times longer than the previous one. I find most ...
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33 votes
2 answers
3k views

Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Correct?

I'm an artist and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors for exoplanets that have atmospheres with a similar chemical composition to ...
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33 votes
3 answers
3k views

What efficiencies make a realistic food chain?

I'm trying to design a food chain. For the sake of argument lets say it's based on flying creatures over a particular mountain range. ...
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  • 18.2k
50 votes
5 answers
8k views

What is the amputationility of a monomolecular wire weapon?

Monomolecular wire weapons are a somewhat common element in science-fiction. Including in this this fantastic image I found while looking into this: Is the only infeasible thing in this image that ...
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53 votes
7 answers
35k views

Creating a realistic world map - Landmass formation

This Query is part of the Worldbuilding Resources Article. This question focuses on the initial creation of landmasses. What are the processes that causes land-masses to form, and continents and ...
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  • 76.2k
126 votes
19 answers
40k views

Could a planet made completely of water exist?

In the Star Trek: Voyager episode "Thirty Days", there was a planet made completely out of water, which is the inspiration for this question. However, that planet was held together by an artificial ...
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  • 31k
25 votes
10 answers
2k views

What's the biggest reasonable natural planet or moon with Earth-like surface gravity?

Sister question to: What's the smallest reasonable natural planet or moon with Earth-like surface gravity? - I want us to have both upper and lower bounds for 1g planets available for authors. We ...
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  • 32.8k
42 votes
8 answers
11k views

How extensive could a habitable twilight zone be on a tidally locked planet?

If a planet always faces the same side to the sun, so that it has a permanent night side and a permanent day side, it will have a twilight zone in between the two sides. This will be a band around the ...
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  • 6,033
12 votes
2 answers
4k views

Creating a scientifically semi-valid super-soldier, part 1: Skeleton [closed]

Sometimes you just want to have a dragon, giant scorpion or a superhuman that has a bit more realism behind it than "it's strong, fast, can jump extreme distances despite it's weight and it's smart, ...
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27 votes
7 answers
7k 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 ...
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31 votes
6 answers
4k views

On the immediate effects of a small, short term black hole

What immediate effects would a small, short-term black hole have if it appeared in a residential backyard? How small or short-lived would it have to be to be survivable, if it is survivable at all? ...
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117 votes
11 answers
24k views

Could a Dwarven Civilization Exist?

Could a Dwarven society as described by Tolkien mythology actually work? Dwarves for the purposes of this question are short, stout, bearded men and women who live primarily underground. They have a ...
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29 votes
8 answers
7k views

How to Breathe Both on Land and Under the SEA

The popular image of a mermaid is a half-fish, half-human creature breathing fine above and below the surface. The only real-life analogy to this are the amphibians - frogs, toads and salamanders. ...
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  • 14.1k
39 votes
11 answers
5k views

Stumped: How can I get a huge Earth-like planet?

I hope this isn't too broad. I would like an Earth-like planet for November's NaNoWriMo that is just enormous, but plausible. Then I started to get into material composition, proximity to the star, ...
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  • 17.3k
34 votes
11 answers
5k views

Is there a scientifically plausible faster-than-light communication system?

In series such as the Hyperion Cantos and Ender's Game, there exist fictional faster-than-light communication systems allowing either instantaneous, or near-instantaneous transmission of information. ...
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50 votes
26 answers
19k views

Advantages of "Spider Mechs" over Tanks?

I've seen the discussion on how bipedal mechs are inferior to treaded and wheeled vehicles in almost every way. However, all of these questions appear to be related to bipedal mechs. I'm wondering if ...
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31 votes
7 answers
22k views

Is there a theoretical maximum size for rocky planets?

As title suggests, what is the size limit by volume for a rocky planet, if any? Some ideas are discussed here, but I'm wondering if there is more concrete, expert evidence to point either way. If ...
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  • 1,199
29 votes
2 answers
906 views

Hydrogenenic Photosynthesis: Strategies for animals

Hydrogenic photosynthesis reduces methane and water to build biomass ($\text{CH}_2\text{O}$) and releases hydrogen: $$\text{CH}_4 + \text{H}_2\text{O} + \text{photons} \to \text{CH}_2\text{O} + 2\...
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  • 4,128
15 votes
3 answers
2k views

How does paradox-free FTL travel affect the details of my story or gameplay?

It is understood that a way to prevent causality violation and time-travel while still having faster-than-light travel is to introduce a specific reference frame. This is explained in detail in this ...
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  • 68.6k
26 votes
2 answers
6k views

How large does a spacecraft need to be to be visible from the surface of the Earth at 400 km altitude?

If a spacecraft is in low earth orbit ~400 Kilometres above earth. How big does it need to be visible from earth with the human eye without telescopes, with enough of its details to clearly ...
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  • 447
16 votes
12 answers
5k views

Why would humans be the dominant species?

Humans, in most fantasy stories including in my own, are the dominant species. Why is that? Firstly, I guess I should give every race in my story strengths and weaknesses. Humans (same as us) have ...
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  • 6,051
9 votes
7 answers
4k views

What is a reasonable amount of population growth for 900 years?

Starting with about 500 humans and allowing for 900 years to pass, about how many people would there be at the end? (Just asking for a rough estimate, maybe a range.) Assuming: People are generally ...
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  • 99
2 votes
4 answers
955 views

Could my Wyverns exist?

A long time ago, Yi Qi diverged into three main groups: Cockatrices, Drakes, and Wyverns. Some characteristics of Wyverns include: They are tetrapods/quadrupeds They are covered with feathers The ...
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  • 6,051
43 votes
14 answers
10k views

Anatomically correct Arachne

In the fantasy culture it's not uncommon to find Giant spiders with the upper body of a human. There are many variants as the spider body having only 4 legs and the upper human body have 2 additional ...
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  • 3,852
29 votes
7 answers
8k views

What is the minimum size of a self-sufficient industrial country?

Imagine there is a country in which there are all important natural resources (oil, gas, metal ores, wood, etc.) in their natural form and which lies in a temperate climate region. There may be some ...
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  • 4,486
29 votes
3 answers
4k views

How tall can a tree grow?

In my fantasy world I want fantastically large trees, particularly in the height category. The tallest trees on earth grow just over 100 meters tall. Why can't they get taller? What circumstances ...
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  • 13.5k
15 votes
8 answers
4k views

Anatomically reasonable respiratory system for human-derived merfolk

This question considers the respiratory apparatus of an aquatic (or amphibious) species descended from engineered humans. The history of the species provides a relevant constraint. While the science ...
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