Questions tagged [earth-like]

For questions regarding planets similar to Earth in most respects. This tag should be used when describing a planet that follows the rules of Earth with exceptions outlined in the question. Usually questions using this tag will be about the differences and the impacts of those differences.

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19
votes
9answers
6k views

Can an earth-like world lack mineable iron?

This question is pretty straightforward. I would like to build an earth-like world in which humans don't have access to iron, or at least can't mine any prior to full scale industrialization. They can ...
1
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1answer
346 views

How close can a moon orbit a planet? [duplicate]

On an Earth-like planet, can I have a natural satellite in a stable orbit so low that it shares an atmosphere with the planet?
26
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7answers
6k views

How can I make manure without cows?

Background There is a world with flora and fauna based on the life forms that evolved on Gondwana (see here for previous questions). Humans colonized this continent from a distant one some thousands ...
16
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7answers
5k views

What could cause the world to be almost completely submerged in water, naturally or man-made?

I'm trying to build a world that is almost completely water, but I couldn't come up with an explanation for WHY the world was like this. The world has the same gravity and atmosphere of Earth. It also ...
8
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1answer
313 views

How would you calculate the habitable surface area on Gliese 667 Cc?

How could I calculate the habitable bounds, in relation to temperature, near the twilight zone of Gliese 667 Cc? Assuming an Earth-like atmosphere and no tidal working. Here are the numbers that I ...
10
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2answers
2k views

How will birds be different on a <1g world?

First, I guess the conditions of the world are in order. It's approximately 85% the mass of earth and there is going to be a full ecosystem with all the usual types of bugs, insects, trees, and ...
1
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0answers
69 views

At what point of the evolution an alien civilisation living in earth-like planet may differ? [closed]

Somewhere in the universe, there is a planet similar to the Earth, with living beings similar to humans: they can find on this planet any resources we can find on earth (water, clay, cooper, ...); ...
21
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13answers
7k views

Under what conditions would humanoids evolve eyes in the backs of their heads?

Many creatures - humans among them - have binocular vision, where two eyes side by side allow good depth perception. There are quite a few other advantages over one eye, including a larger field of ...
16
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11answers
6k views

What is the smallest geological change possible to make human evolution untraceable?

Human evolution has a reasonably complete fossil record pointing to the fact that we and apes evolved from a common ancestor within the last 10 million years or so. But I want a world where it could ...
3
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3answers
185 views

Is it possible to have a fictional home-bearing huge tree?

I wrote a story in which humans live on huge trees on a fictional habitable planet similar to earth. the tree would be even more huge than the hometree from avatar. The tree is not taller than the ...
29
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2answers
1k 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 ...
54
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10answers
7k views

What could cause sugary rain?

In a world very similar to ours, rain has a high concentration of simple carbohydrates in it, enough to sustain life on the surface. After some rainfall, this sugary rainwater is left behind and some ...
4
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2answers
113 views

How would 20th century era warfare differ on an Earth-like planet with a thinner atmosphere at sea level? [closed]

I answered this question by theorizing that making a world's atmosphere thinner at sea level could limit the viability of airplanes used in naval warfare. My reasoning was that a thinner atmosphere ...
18
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18answers
6k views

Can a civilization be reduced to the Stone age by a conventional war?

I need to arrange a situation in which a major conflict occurs in a relatively advanced civilization and where the fighting is of such a magnitude that all the participants are eventually reduced to ...
6
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2answers
346 views

Would residents of a small planet realize the planet is small?

I am considering setting my next D&D campaign on an earthlike but small planet. By "small," I am imagining a world that still feels vast, yet is circumnavigable over land and/or water with low or ...
10
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4answers
1k views

Earth-like planet with tundra or taiga as dominant biomes?

What would be the hypothetical conditions for an Earth-like planet to have tundra or taiga as dominant biomes?
3
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3answers
186 views

Is there dry land on Earth if the moon orbits just above its Roche limit?

Imagine an Earth-like world in all respects except that the Moon is much much closer. I think I’m right to say if the Moon were very close that tidal forces would slowly rob it of momentum and it ...
8
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2answers
1k views

Rock formations & islands on a moon with megamareal tides

This concerns a habitable, earthlike moon orbiting a gas giant, which is not tidal locked, and has an elliptical orbit eccentric enough to avoid frequent deep winter freezes (the freezes do happen, ...
4
votes
2answers
142 views

Effects on Earths development if 95% of the water was missing? [closed]

If a planet just like Earth formed but with 95% less water than on our world, what effect would this have on the development of the planet – in outline. Things to consider, might we still see plate ...
4
votes
2answers
221 views

Why would plants on an Earth-like planets photosynthesize without using blue-wavelength light?

According to Wikipedia, ...plants are green because chlorophyll reflects green light. And chlorophyll is found in all plants because it is the molecule that absorbs the light that is used to make ...
36
votes
12answers
8k views

How to stop a massive canal system from silting up?

Based on the desert world from this question I need to transport around 500 cubic kilometres of water / year across a desert. Using this calculator. this can be achieved if the main feeder canal is ...
2
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4answers
537 views

Roughly how much water would my desert civilization need every year?

In my desert canal world all water is supplied from the poles to the temperate zones via a canal network. I want to work out the amount of water that that is needed, so that I can work out the ...
3
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4answers
310 views

How fast a current can ancient water way travel overcome?

This question has similarities to this one but concerns canal travel in more ancient times and is aimed at finding an approximate speed of flow not variables. Background Assume an Earth-like world ...
3
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1answer
231 views

Which impacts are to be expected, if an Earth-like planet orbits a Jupiter-like one?

In a fictional setting, an Earth-like planet is orbiting another, Jupiter-like planet. For explanation see my previous question Which astronomical or cosmological event would explain periodical low-...
13
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7answers
3k views

Maximum habitability of a planet with no indigenous life

I've been thinking about terraforming and planets in general. We can look at the planets we know that might be terraformable - Venus and Mars - and understand the technical requirements for doing so. ...
0
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2answers
98 views

Behavior of two separate(by planet) Human societies towards each other. [closed]

Lets say in this solar system, there are two planets, always on the direct opposite sides of their sun. Both planets are not capable of light speed travel or even at the advanced technological level ...
1
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7answers
558 views

How can an ultra-deep hole or canyon form naturally on an earth like world? [duplicate]

How can an ultra-deep hole or canyon form naturally on an earth like world? By ultra-deep I’m thinking something like the Marianas Trench but on land and not filled with water. If it’s not possible ...
10
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5answers
441 views

Which astronomical or cosmological event would explain periodical low-grav-effect on earth-like planet?

Imagine an earth-like planet on which gravity is reduced by 20%-30% every 15 months. The low-grav-effect should start slowly, reaching its peak/bottom of round about 0.7 g after 6 weeks and should ...
7
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3answers
1k views

How to determine the population size and spread in a fictional ancient world settling

Similar question to this one except I want to calculate the urban and rural population needed to support an army. I want to create a world for a fantasy wargame campaign using some of the elements ...
6
votes
3answers
141 views

How to create an intelligent species that lives in villages on trees like leaf cutter ants and have castes(like social insects and/or mole rats)? [closed]

I want to create an intelligent creature(grit) that has a eusocial social system. They need to be small(10-20cm height) and live in small towns on top of the canopy of tropical forests. by ...
6
votes
3answers
378 views

Can a 25 mile high volcano form naturally on a desiccated desert earth planet?

The enormous shield volcano that this question was based on was held up by magic or God. It presented some very interesting conditions for alternate worlds so I thought I would develop that train of ...
9
votes
3answers
748 views

How to craze the surface of a planet?

I want to generate a world with a surface that has the same sort of patterning is seen in the surface of a dried lake bed when the mud cracks, but greatly scaled up. Each individual plate/fragment of ...
8
votes
5answers
626 views

How to get an extreme temperature range between equator and poles without tidal locking

How can I arrange for a planet to have a much greater temperature range between the poles and the equator without it being tidally locked? Edit: By “much greater” I mean the temperature at the poles ...
16
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9answers
4k views

How could a Great Chasm be created?

As one of the feature in my world, I want to create a very deep chasm, as deep as possible. If it can touch the core, it will be perfect. Size does not actually matters, although I think the ...
3
votes
0answers
97 views

Habitable Antarcticas [closed]

I'm curious about a couple of scenarios involving a habitable or partially-habitable Antarctica. I'm not all that concerned about how to get there from present-day Earth, though it might be ...
2
votes
4answers
312 views

What would be the key differences between real-world nuclear warfare and alternate reality where each nation has only a single thermonuclear weapon?

Consider an Earth-like world where every nation in the world agreed to dismantle and divide all nuclear arsenals so that every nation was allowed only a single 50 megaton thermonuclear bomb (equipped ...
16
votes
5answers
2k views

What would produce the most uneven but earthlike planetary surface?

What planetary parameters such as plate tectonics and volcanism etc would best encourage the most uneven planetary surface on an earth like planet? I want a world to be covered in very uneven terrain,...
19
votes
8answers
7k views

Blue soil (aka dirt) in an earth-like planet?

How could blue soil exist, in a realistic earth-like world. The world may even be earth. First off is it even possible - could soil like this exist given the requirements below? (if not then why?) ...
2
votes
9answers
802 views

Technology for a sci-fi airship

Sometimes old, discredited or impractical ideas come back to favor, because a new technology has evolved. Let us imagine a future Earth-like world (not early 20th century or steampunk) that would ...
2
votes
1answer
301 views

What If Earth Had an Equatorial Ridge

Saturnian moons Iapetus, Atlas, and Pan all have equatorial ridges. There's a few explanations as to why, but the theory behind why Iapetus has one is what intrigues me. (https://en.m.wikipedia.org/...
4
votes
2answers
184 views

Is this an accurate simulation of a further south Australia with a filled lake Eyre?

I created this climate map based on the Koppen Climate Classification map. In this scenario Australia is moved 10 degrees of latitude further south and the Lake Eyre basin is filled (shown in map.) Is ...
0
votes
1answer
124 views

What is the upper size limit on aquatic creatures? [duplicate]

I'm developing a planet populated by giant sea creatures (think Megalodon, but bigger.) While I know that gravity has an effect on size, the sources I found only made reference to land creatures, who ...
0
votes
2answers
121 views

How would environmental factors affect a giant rideable moth/butterfly? [duplicate]

If rideable-sized butterflies/moths were possible, how might environmental factors (e.g. climate, temperature, altitude) affect them? If the square-cube ratio issue could be overcome, and it could ...
-3
votes
3answers
156 views

How much variation is possible among planets with “Earth-like” surface gravity? [closed]

What is the possible range of variation among planets with Earth-like surface gravity, and what limitations could we expect on this variation assuming the planets were formed by natural processes? For ...
5
votes
4answers
234 views

What is the smallest change that would allow an Earth-like planet to have atmospheric CO₂ levels of several percent?

Start with a planet just like Earth as of today (whatever today means when you are reading this). For simplicity's sake, disregard mankind's continuous spewing of greenhouse gases into the atmosphere; ...
3
votes
2answers
980 views

How many moons can form around this alternate Earth?

Say in an alternate timeline, Earth developed with more moons. Many, many many more moons. In fact, it developed with the absolute maximum amount of moons a planet of its size and mass can physically ...
5
votes
3answers
286 views

Plant/mineral that could preserve fresh meat without anything other than fire?

My character kills a goat in the mountains and eats some of it for dinner. What kind of plant or mineral could he use to preserve the meat to carry with him so that it stays fresh and doesn't become ...
4
votes
5answers
893 views

What would plant life be like on an earth-like planet with extremely low gravity

I will be writing a short story about humans landing on an earth-like forest planet with a gravitational force of about 3 meters per second squared (In contrast, Earth has a gravitational acceleration ...
4
votes
2answers
441 views

Could life on earth survive after the sun becomes a white dwarf?

It's my first time writing an original story and I have this idea, but I don't know if it could be scientifically feasible. My story would be medieval fantasy with magic, but I wanted to add a twist ...
7
votes
2answers
204 views

How to calculate maximum altitude difference between metro stations?

For story purpose I am trying to design a mass transit system for a perfect city. Right ... maybe not so perfect, if you look carefully into the details, but actually the mass transit system is ...

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