Questions tagged [alternate-earth]

This tag is for questions relating to radically changed Earth. This alternate Earth could be a post-apocalyptic Earth, or Earth with major changes in the current social/political/economical schemes.

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How might a lower gravity planet sustain a warm, earth-like atmosphere?

I've already posted something similar recently, but I don't think I was really asking the right question. I'm designing a hypothetical lower-gravity planet with 0.47M, 0.79r and 0.76g, with a similar ...
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If Earth was less massive, with 25% less gravity and an atmosphere scaled down proportionately, how would that affect climate?

Everything else being equal, how would reduced planetary mass and gravity affect the behavior of the atmosphere and the climate?
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Would these changes alter the effects of Tornado Alley?

Here is how the meteorological danger zone called "Tornado Alley" is made: Warm, moist air from the Gulf of Mexico mixes with cold, dry air from the mountains and warm, dry air from the ...
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What's the impact of an Australia-sized continent near South America?

I have an idea for a story set in an alternate world where an Australia-sized continent exists near South America, near Chile. Question: what would the climate of this world would be, if this ...
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6 votes
3 answers
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Which marine organisms would survive this longer Paleocene-Eocene Thermal Maximum?

56 million years ago, Earth underwent the greatest rise in temperature in the last 100 million years. In just 20 to 50 millennia, the global temperature had risen by five to eight degrees Celsius (...
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8 votes
2 answers
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How far across the sea can mosquitoes disperse?

One of the more interesting facts about the biogeography of Hawaii is that mosquitoes were not always present; they only arrived in the early nineteenth century, as stowaways aboard oceangoing ships. ...
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2 votes
4 answers
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Most hospitable biomes for living off the land

I'm trying to figure out which are the most hospitable biomes for living off the land. Say we have a small spacecraft fallen through a time warp that takes it sideways in time, where it finds itself ...
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What changes to a humans physical form would occur if society lived inside the Earth?

(Mandatory I am new here, hello, nice to meet some fellow world builders, sorry for any mistakes, yikkity yak and all that) In my "world", it has been 500 years since the majority of human ...
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1 answer
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What Would Be The Technological Limitations of a Civilization That Never Developed the Concept of Zero? [duplicate]

I have been brainstorming a short-story idea about an advanced civilization that develops on earth 60 million years after humans go extinct. Said civilization discovers time travel and decides to meet ...
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5 votes
2 answers
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Is this sort of life cycle on a megamangrove feasible?

Point of departure--56 million years ago, in which the Paleocene-Eocene Thermal Maximum lasted three to four times longer than it did in our timeline. Today, on this alternate Earth, the twilight ...
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7 votes
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These Primates Don't Look Like Primates. How to Fix Them

For years, I've been building and rebuilding an alternate Earth. The point of departure is 56 million years ago, when the hottest episode in the last 100 million years, the Paleocene-Eocene Thermal ...
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Could a river civilization develop in a cold desert climate?

There seems to be a trend with the oldest civilizations (Civilizations being urbanized societies with a government and social heirarchy) starting around river valleys surrounded by desert; the ...
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Could a hypothetical planet composed of a neon-oxygen or argon-oxygen atmosphere with Earth-like pressure levels sustain life?

I'm trying to create a hypothetical planet scenario, where there is a planet that has a similar atmospheric pressure to that of Earth, but in this case, it has a gas different than that of nitrogen. ...
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Would a longer PETM make Earth hotter than it was?

Sometime between the Paleocene and Eocene epochs, there was a mysterious, sudden, dramatic rise in global temperature. This moment in time was known as the "Paleocene-Eocene Thermal Maximum",...
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1 vote
1 answer
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What would the equator be like if Modern-Day Earth were as hot as the Cambrian?

This is a map of Earth's climate today: This is how the Koppen classification colors the particular climates, so I don't know why the lower latitudes were dominated by several shades of the color ...
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3 votes
3 answers
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Can a new geological material (specifically, a metal) be formed no older than 56 million years ago?

There is an alternate Earth that I've been building and rebuilding for years. The canonized point of departure is 56 million years ago, specifically a Paleocene-Eocene Thermal Maximum that is four to ...
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2 votes
2 answers
143 views

Could a coalition of powerful corporations protect itself from a hostile neighbour?

This is an alternative Earth-like world, which has just entered the rough equivalent of Cold War. The primary contenders are the large quasi-socialist country with a strong command economy, opposed by ...
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What's the minimum height of a mountain resolvable to the human eye from 800 miles on a flat Earth?

The Taniquetil / Oiolossë (Mount Everwhite) on the eastern shore of Aman is the tallest mountain on Arda. Far higher than the other Pelóri, it could be seen from the mountain Meneltarma on Númenor ...
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1 vote
2 answers
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What is the habitability of an Earth- like habitable planet that do not have any cloud covering?

Let's say I imagined a world that is as habitable as Earth and has the same oxygen levels, land to ocean ratio and similar average temperature. However it has no clouds at all. How different its ...
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0 votes
2 answers
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How can these people fight these monsters? [closed]

On an alternate earth, lethal Pliosaurs size creatures infest the ocean, making sea travel impossible. Their cousin species tries to invade the surface every five years. The advantages of this ...
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13 votes
23 answers
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Reasons why a high tech species does not have space travel

I am writing a story where humanity has advanced technology, but I want to give a justification for why they are still on their planet. Here humanity has advanced ai, superconductors, laser weapons ...
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8 votes
2 answers
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Ice coverage of a horizontal torus planet

How much ice would a torus planet be covered in if it rotated horizontally without a tilt such that its inner region never sees sunlight? It's basically earth but as a torus and a completely '...
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7 votes
1 answer
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Ranges of aurochs, bison and wild horses

I'm working on a setting where one of the large continents is similar to North America before the arrival of humans, including a biome containing the three large grazing ungulate species: aurochs, ...
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1 vote
2 answers
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Would You Fit All the Domesticated Animals on This One Continent?

There is an alternate Earth somewhere in the multiverse, one in which there are three continents, all separated by an interconnected network of seaways that make up only 45% of the planet's surface (...
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2 votes
1 answer
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What would the climate and ecosystems be like if instead of water, land would be 71% of Earth's surface?

According to the Bureau of Reclamation, water covers about 71% of the Earth's surface. Everything from microbes in the ocean releasing greenhouse gases into the air, to the immense amount of water ...
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12 votes
13 answers
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In a world of groovy super spies, how would a spy cross a ravine?

I'm developing an alternate Earth where super spies exist. Men and women of extraordinary skill with extraordinary gadgets who act in extraordinary ways to protect the proverbial "King and ...
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6 votes
3 answers
129 views

Nesting abilities of migratory interdimensional creature

I'm waving hands a fair bit here, and I am doing that because I believe that it is internally coherent, so if you accept these things, you shouldn't need the story to suggest answers. I'm including as ...
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2 votes
1 answer
114 views

Substitutes for lead-acid batteries

I'm writing about a setting which will be developing an industrial civilization on a planet similar to Earth in relevant ways, except that certain heavy metals such as lead, are much rarer. (Other ...
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3 votes
1 answer
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How to Turn Protoceratops Into a Real-Live Griffin

It was believed that the discovery of a small, herbivorous dinosaur named Protoceratops was the inspiration for the creation of the iconic griffin, a belief challenged in 2016 by paleontologist Mark ...
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4 votes
6 answers
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Preserving information for future humans

I'm conceptualizing a sci-fi short story. In it, the main character will find an obelisk type object which has been half-buried for who knows how long. Well, the answer is about 20,000 years. The ...
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1 vote
2 answers
132 views

Could a second Trojan moon orbit Earth, as in, a second moon orbiting Earth from the same distance as our moon?

Here's the basic gist about our moon--it's one-quarter the width and one-eighth the gravity of Earth, it's rocky, it has no atmosphere and it orbits Earth from a distance of approximately 240,000 ...
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4 votes
1 answer
109 views

Effects of a sudden change in magnetic poles

In my verse the Magnetic Poles of the planet underwent a sudden shift due to the construction of a great tower imbued with great amounts of Magic. This shift made it so that the poles shifted to the ...
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4 votes
2 answers
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What POD Would I Need For Earth's Lost Worlds to Exist Today?

This is a map of Earth as depicted by the DeviantArtist ToonHolt: As you can see, many new landmasses have been added, from lost worlds like Sundaland, Zealandia and Kerguelen, to fictional worlds ...
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2 votes
2 answers
115 views

Naturally occurring temperate meadows

On a largely uninhabited world with geology, climate, biome etc very similar to prehistoric Earth, I have some scenes taking place in a temperate grassland. It's at moderately high altitude, and I ...
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3 votes
3 answers
183 views

Without tides, would we have beaches?

Consider a world similar in most ways to Earth, except with no tides. (No moon, and for some reason outside the scope of this question, solar tides are negligible.) Would it have beaches as we know ...
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0 votes
1 answer
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What will Earth's orbit around the sun look like if it were standing at an axial tilt of 66.5 degrees? [closed]

Earth currently stands at an axial tilt of 23.5 degrees, low enough for seasons to form. Here is the diagram below: In the spring and autumn months, Earth parallel to the sun. In the summer, it ...
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6 votes
3 answers
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How species-specific are tropical diseases and parasites?

Following on from a recent question about animals, concerning a group of people traveling sideways in time, to a world that resembles Earth as it would have been had humans never evolved, it occurs to ...
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3 votes
2 answers
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How feasible would a Gaza - Gulf of Akaba canal be, purely technically speaking?

Note: partially inspired by the recent ship that ran aground in the Suez canal. In my alternate history novel, I'd like there to be a second Red Sea-Mediterranean Sea canal roughly along what's in our ...
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33 votes
10 answers
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How dangerous are animals with no history of human contact?

Wild animals like wolves, lions and bears rarely attack people. They behave as though they know humans are dangerous and generally best avoided. Imagine a group of people traveling sideways in time, ...
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1 vote
2 answers
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How much pressure would sea level be if the atmosphere were as thick as mentioned below?

Here is how thick our atmosphere is: Troposphere: 7-20 kilometers Stratosphere: 20-50 kilometers Mesosphere: 50-85 kilometers Thermosphere: 90-1,000 kilometers Here is the thickness of the ...
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1 vote
3 answers
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Roughly how many levels of command were there in a large WW2 army?

I want to build the command structure for a WW2 technology level fictional army. I’m struggling with all of the different units and especially the HQ’s. I need to understand how a real army of this ...
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3 votes
5 answers
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How many species does a virus need to infect to destroy life on Earth? [closed]

Okay, let's say that there's a virus that can infect multiple species, is very hard to cure, extremely contagious, can linger asymptomatically for long periods of time, and likely to be deadly. It ...
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-3 votes
2 answers
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How Bright Would a "Summer" Night Be on This Extreme Alternate Earth?

Here is the oversimplified map of the solar system of an alternate Earth: It is actually two separate binaries--one consisting of a red giant 100 times as wide, one-third as massive and 1,000 times ...
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5 votes
2 answers
630 views

Is The Climate Map for My Alternate Earth Accurate?

Here is a map of an alternate Earth that I've been building and rebuilding for years: To make things easier on all of us, myself included especially, at the bottom left is a legend on this world's ...
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6 votes
2 answers
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Dodgy Radio Communications

This question relates the same world discussed in this post: Horseback Travel in an Unpopulated Pacific Northwest Two mounted patrolmen are tasked with navigating and policing a reimagined Coastal PNW,...
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1 vote
0 answers
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Effects on World Climate without (Most of) northwest and central Europe

So I'm considering creating a fantasy setting heavily modelled on Earth with the exception that most of what we consider Northwest and Central Europe is replaced by sea. I decided to as a reference ...
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4 votes
4 answers
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What Would the Climate Be Like on this Extreme Alternate Earth?

In an alternate universe, Earth orbits not one sun, but two. As you can see, both stars are orange dwarves, each one only 40% as bright as our sun. All the same, this alternate Earth orbits from ...
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4 votes
2 answers
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In This Picture, How Far Can One Binary Orbit the Other?

In an alternate Milky Way in an alternate universe, there is a cluster of stars so dense that nights are over 60 times brighter than our full moon. In that cluster is a solar system presented (albeit ...
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5 votes
3 answers
267 views

How would medieval Europeans react to discovery of fantasy races? [closed]

My question is inspired by this question Infinite flat world Basically instead of the Earth being a planet it is instead a small portion of an Alderson Disk. According to the writer Larry Niven "...
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6 votes
8 answers
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Navigating under a starless sky: how to determine the position?

My alternate Earth is placed, together with the whole solar system and nothing else, in the center of the Boötes void. At nearly 330 million light-years in diameter (approximately 0.27% of the ...
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