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Questions tagged [science-based]

For questions that require answers based on hard science, not magic or pseudo-science, but do not require scientific citations. Contrast with the hard-science and reality-check tags. Do not use this tag as the only tag on a question.

69
votes
17answers
16k 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 ...
67
votes
11answers
54k 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? ...
172
votes
18answers
62k 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 ...
52
votes
9answers
6k 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 ...
63
votes
4answers
6k 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 ...
64
votes
24answers
9k 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 ...
38
votes
7answers
8k 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 ...
42
votes
8answers
9k 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 ...
24
votes
7answers
4k 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 ...
53
votes
6answers
13k 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 ...
55
votes
6answers
10k 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 ...
54
votes
3answers
20k views

Creating a realistic world map - Currents, Precipitation and Climate

Once geological processes and erosion have created a landscape this landscape will in turn alter the planet. Ocean currents and trade winds will tend to form and certain weather patterns will emerge. ...
85
votes
14answers
9k 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 ...
36
votes
2answers
9k 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 ...
60
votes
29answers
14k 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 ...
35
votes
4answers
7k 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 ...
41
votes
5answers
5k 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. ...
41
votes
21answers
10k 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 ...
47
votes
3answers
13k 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 ...
48
votes
5answers
5k 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 ...
30
votes
3answers
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. ...
51
votes
7answers
28k views

Creating a realistic world map - Landmass formation

This question focuses on the initial creation of landmasses. What are the processes that causes land-masses to form, and continents and islands to rise up from the sea and sink back into it? How can ...
115
votes
18answers
31k 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 ...
38
votes
10answers
53k 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 ...
35
votes
6answers
5k 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 ...
71
votes
20answers
6k 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 ...
30
votes
9answers
4k 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. ...
24
votes
2answers
589 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\...
25
votes
7answers
6k 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 ...
12
votes
3answers
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 ...
99
votes
10answers
17k 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 ...
25
votes
7answers
6k 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. ...
37
votes
11answers
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, ...
31
votes
6answers
3k 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? ...
26
votes
2answers
5k 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 ...
17
votes
5answers
954 views

How can I safely brighten my secondary star?

I have an earth-like planet orbiting one of the stars in a binary system. I have learned that, for G-class stars, if the secondary star is 100AU from the primary one, I can expect the secondary star ...
11
votes
4answers
523 views

Creating a scientifically semi-valid super-soldier, part 3: Physical shock resistance

Part 1 here: Creating a scientifically semi-valid super-soldier, part 1: Skeleton Part 2 here: Creating a scientifically semi-valid super-soldier, part 2: nervous system In most movies, comics and ...
44
votes
9answers
5k views

Wondering what would happen if magic was constrained by Conservation of Energy

Would throwing a fireball leave a trail of frost in its wake? Would transmuting too much lead into gold cause a small meltdown? Would collecting enough power to cast a really big spell like causing ...
29
votes
3answers
3k 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 ...
36
votes
10answers
11k views

How can I destroy a gas giant planet?

We have already discussed how difficult it would be to blow up a planet like Earth, basically deciding that you can't do that with any reasonable amounts of energy. But what if I don't need to blow up ...
25
votes
10answers
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 ...
23
votes
7answers
30k views

How would the human body develop under a different gravity?

What would be the effects of high or low gravity on human body development? How would the human body develop under a different gravity? Many science fiction stories explore the idea that people from ...
22
votes
3answers
764 views

How much land area do my land-based animals (herbivores) need for food?

I'm trying to work out the kinks of an ecosystem on a planet that is rather similar to Earth, but with some species of animal (both carnivores and herbivores) we aren't familiar with in our world. The ...
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 ...
23
votes
6answers
15k 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 ...
6
votes
2answers
1k 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, ...
25
votes
8answers
4k views

Can an atmosphere englobe a planetary ring?

Would it be possible for the atmosphere of a planet to reach beyond its planetary ring so that earth-like biology could develop on some of the asteroids there? This question is mainly about whether ...
19
votes
3answers
6k 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'...
13
votes
2answers
1k views

Orbiting one star in a binary system: what are the effects of the second star on the planet?

This blog post about binary-star systems points out that, rather having the stars be close together, they could be far apart and a planet might orbit just one of them. It gives the example of the ...
16
votes
10answers
5k views

Could humans alter the moon's orbit significantly with current technology?

A terrible virus has made most of the populations and government officials of the largest superpowers on Earth stark, raving mad, without depriving them of their intelligence. They have decided that ...