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80 votes
Accepted

Reasons for my dark ages world to have no horses at all

The horses cannot be domesticated You say... It is useful to my story line to eliminate horses as a mode of fast travel Well then, that is easy. In your alternate world... Horses have the ...
MichaelK's user avatar
  • 43.9k
54 votes

How can I prevent hyper evolved versions of regular creatures from wiping out their cousins?

Hydras would not compete with snakes Most snakes eat rodents, or other small animals. Even large constrictors don't generally eat adult-human-sized prey. Assuming that hydras would be interested in ...
Jedediah's user avatar
  • 10.8k
48 votes
Accepted

What would happen to a modern skyscraper if it rains micro blackholes?

would it triggers extinction level event? Since they'd evaporate more or less instantaneously (known as Hawking radiation), releasing energy according to the famous equation beginning E=, the ...
Escaped dental patient.'s user avatar
45 votes
Accepted

Is this state of Earth possible, after humans left for a million years?

•98% of all the landmass is wasteland/desert •The two poles are some big chunks of ice, each covering about 20% of earths area This is rather confusing. Yes, I get that there are also cold deserts, ...
L.Dutch's user avatar
  • 291k
43 votes
Accepted

How can AI know that all humans are dead?

Refa's Supplies Run Low Every time Refa has maintenance, her supplies are topped off. Refa can only run for a few hundred years without supplies. Solar panels wear out, chemicals are used, hard drives ...
codeMonkey's user avatar
  • 11.1k
42 votes

When will the last unambiguous evidence of mankind disappear?

If enough time goes by, there would fewer and fewer signs on the surface of the Earth for someone looking for past intelligent life. However, as soon as someone wants to build any infrastructure or ...
IKM's user avatar
  • 551
38 votes

99.9% of the flight-capable birds died at once. How screwed is the rest of the world?

Insects swarm, crops die, people starve, society collapses The death of all birds would be apocalyptic in short order. While John O's question covers a lot of aspects of birds' place in the ecosystem, ...
Daniel B's user avatar
  • 19.8k
35 votes
Accepted

What could explain why trees only have 12 rings?

Every fourteen thirteen years, vast swarms of a locust-like creature emerge from underground, where they have been living in the larval stage for all this time. The swarm darkens the sky, and eats ...
plasticinsect's user avatar
35 votes

Virus extinction at the snap of a finger. Can life on Earth continue to exist normally?

Probably Everyone (and Most Animals) Die There's actually an article on exactly this. What we do know is that phages, or the viruses that infect bacteria, are extremely important. Their name comes ...
jdunlop's user avatar
  • 32.1k
34 votes
Accepted

Would humanity go extinct if pleasure ceases?

No. The drive to have a child is one of the strongest ones out there. Not everyone wants a child of course, but a great many people do. We humans may get children via intercourse but that is not ...
Cyn's user avatar
  • 20.4k
33 votes
Accepted

The weird case of the unresponsive Earth - why does the Earth stop communicating with Mars?

A massive solar flare was emitted by the sun and engulfed both earth and the moon but mars was no-where near that part of the solar system. The flare was extremely powerful, far more so than any on ...
Tim B's user avatar
  • 77.1k
32 votes

How can I prevent hyper evolved versions of regular creatures from wiping out their cousins?

Make the super animals depend on mana to live, and move the mana around. As it passes through any given area it moves slowly enough that the animals change, but fast enough that the super animals don'...
The Square-Cube Law's user avatar
32 votes
Accepted

When will the last unambiguous evidence of mankind disappear?

Post-Edit: With orbital multispectral imaging available there is no way that any remains of our cities will be missed. Some of those remains won't last long, geologically speaking, but others will ...
Ash's user avatar
  • 45.6k
32 votes

How can AI know that all humans are dead?

check your inbox : no updates since a few years ... Check the internet : no connection ... Check visually around the lair, with that camera at top of the mountain. The big city 50 km away is now in ...
Cthu's user avatar
  • 431
31 votes

How can AI know that all humans are dead?

It's easy: send out the killbots. Have them report back every year or so with a murder-tally. If they consistently report 0 (or close enough) then humans are extinct. The humans might try to fight ...
Borgh's user avatar
  • 3,450
30 votes

War in a dystopian setting

A rumour that that other country(or whatever else) has fertile women or men and some government decides that they have the military power to acquire them for their own country. If the rumour is not ...
Real Subtle's user avatar
  • 4,731
29 votes
Accepted

Doomsday-clock for my fantasy planet

Your assumption is reasonable, as Tidal Heating is the reason that Io is the most geologically active body in our Solar System. Although, a problem with using Tidal heating is that the energy is ...
Chronocidal's user avatar
  • 15.3k
28 votes

When will the last unambiguous evidence of mankind disappear?

probably longer than the earth has. Fossilization is a thing, and we have set up many things in perfects places to be fossilized. We bury things in salt mines, seal things in glass, bury massive ...
John's user avatar
  • 81.5k
27 votes

Reasons for my dark ages world to have no horses at all

My suggestion is to write the story without horses. In-universe, no one knows what a horse is, so no one wonders why they became extinct/never evolved first place. Meta-universe, if the story is ...
Luís Henrique's user avatar
27 votes

Gravity alteration as extermination tool viable?

https://en.wikipedia.org/wiki/G-force#Human_tolerance According to Wikipedia, 16g for a minute are already deadly. For a day 10g are very much lethal for humans, as well as for any large animal. ...
Whitecold's user avatar
  • 2,678
26 votes

Human response to an existential threat that isn't

"if faced with a potent existential threat, in the form of an outside force, how will the human race respond?" Especially if contact is infrequent, I think we'd go about our lives as normal, quashing ...
Snark218's user avatar
  • 619
26 votes

An iron rain to starve a planet

Removing the oxygen this way will remove much of the atmosphere Earth's atmosphere is $5\times10^{18}$ kg. Nitrogen and Oxygen are the primary components and are approximately equal in mass. 20% of ...
kingledion's user avatar
  • 85.5k
25 votes

What would happen to a modern skyscraper if it rains micro blackholes?

Black holes evaporate by emitting Hawking radiation a 1-second-life black hole has a mass of $2.28 \cdot 10^5 \ \mathrm{kg}$ A grape has far less mass than that, thus the black hole would ...
L.Dutch's user avatar
  • 291k
24 votes

How to make advanced future humans extinct/get rid of them?

/ the whole extinct humans thing is just a backdrop/ Then you don't need to be specific. And this unresolved issue can be grist for your prose mill. Whatever protagonists carry your story through ...
Willk's user avatar
  • 305k
23 votes

How can a human cause the Yellowstone to erupt?

There is no easy way to make it erupt Sure you could say drill a deep enough hole and fill it with explosives or an H-bomb and let it go. But the key here is pressure. For Yellowstone to be an ...
anon's user avatar
  • 11.3k
23 votes

Conquering the Galaxy with DNA - What is the best vector?

Cockroaches don't live up to their reputation. The domestic cockroach that seems so hard to kill is as dependent on our warm comfortable environment as we are. If you want to clear an infestation in a ...
Separatrix's user avatar
  • 118k
22 votes

The weird case of the unresponsive Earth - why does the Earth stop communicating with Mars?

The origins of this mystery dates back to early 2000's. The small SETI office in the Hat Creek Observatory was filled with the noise of computers beeping and buzzing. They had just detected an alien ...
Rakesh Gopal's user avatar
  • 1,486
21 votes
Accepted

Is it necessary to wipe out vile man-eating dragons?

It's all in how we perceive them, but regardless it is not a good idea to drive a species to extinction. Take Grizzly Bears. They are aggressive, can kill you if you get close, often exist close to ...
flox's user avatar
  • 22.2k
19 votes

Is this state of Earth possible, after humans left for a million years?

You're positing a world that has no surface plants. That's... implausible. There are plants out there that can manage climatic extremes far worse than anything humans could live through. Plants ...
Ben Barden's user avatar
  • 1,427
19 votes

Is it necessary to wipe out vile man-eating dragons?

It is an unwise act to destroy a potential advantage. If dragons appeared overnight they are very much an unknown quantity and therefore still a potential advantage (notwithstanding their inherent ...
Adrian K-B.'s user avatar
  • 3,113

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