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244 votes
Accepted

Everything alive in the world dies this instant. Without bacteria to decompose anything, what happens to the remains? What does this look like?

They weather. https://www.livescience.com/18343-seal-mummies-antarctic-microbes.html Antarctica has dry valleys where, for some reasons, seals sometimes went. It is a bad place for seals, and they ...
Willk's user avatar
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228 votes

Can a substance be more lethal in smaller doses?

What you're looking for is an emetic - a substance that induces vomiting. This is the specific reason why, as @Alberto Yagos already stated in his answer, suicide-by-pills doesn't always work - many ...
F1Krazy's user avatar
  • 14.2k
159 votes

How can waste from the body be removed without being expelled from the anus?

Wastes are incorporated into hair. Wonder how the elves accomplish their flowing locks? How an elf seems able to try a new hairstyle every week? It is all about the hair. The elven keratinocytes ...
Willk's user avatar
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140 votes

Is there an evolutionary advantage to having two heads?

In this world, bodies are more durable than intelligence. Imagine mineral creatures who accumulate bodies of crystals, metals and minerals. It takes a really long time to grow a good body and lots ...
Willk's user avatar
  • 305k
128 votes

Everything alive in the world dies this instant. Without bacteria to decompose anything, what happens to the remains? What does this look like?

The remains would mummify, petrify, erode, and eventually become just another mineral layer. Where water is available the organic remains will dissolve and be replaced with inorganic minerals to ...
Giter's user avatar
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127 votes
Accepted

Lembas bread (2000 kCalories per bite)

It just doesn't add up if you only consider real world nutritional chemistry. The most calorie-dense food available is fat at 9 calories/gram. That's 220 grams to hit 2000 calories, nearly a quarter ...
SudoSedWinifred's user avatar
125 votes
Accepted

Given immortality can animals become intelligent?

Evidence suggests that no creature becomes more intelligent than it needs to be, intelligence is expensive of calories, for example, human brains are about 2% of our overall mass but require 20% of ...
Ash's user avatar
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123 votes
Accepted

Why would vampires be incapable of entering a non-vampire human’s house uninvited?

I think you can approach it from three different avenues, depending on the tone of your setting: Psychological: Perhaps the root cause of vampirism in this world (such as a virus), inflicts an ...
Liesmith's user avatar
  • 6,838
121 votes

How would predation work in an empathic universe?

You’re neglecting an important arena in the predator/prey dynamic: Thought. If your predators can feel the thoughts of things around them and the prey can detect predatory intent, what’s to stop the ...
Joe Bloggs's user avatar
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120 votes

Why Do My Super-Soldiers Constantly Mutter Their Thoughts Out Loud?

The engineers were not concerned about their creations rebelling Hmm ... engineers ... their creations ... These soldiers are clearly machines, even if not electronic in anyway. Let's say ...
The Square-Cube Law's user avatar
112 votes

What could cause sugary rain?

The rain is actually the blood of billions. A species on a nearby planet is being harvested by a technologically advanced alien civilization and the specimens are drained of all their internal ...
A. C. A. C.'s user avatar
  • 2,790
107 votes
Accepted

Does a grenade kill you the same way a gun does?

What a wonderfully macabre question! This calls for cited sources! First off, I'd like to point out that you are correct to notice the similarities between a grenade and a rifle round. Both have ...
Cort Ammon's user avatar
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105 votes
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Why don't future civilizations develop their A.I. to integrate with biology so they can make a sustainable world?

I work in the AI field. The fictional shows are not realistic, the authors do that for the sake of creating a powerful enemy that seems unstoppable, so the puny humans can be heroic in the eyes of the ...
Amadeus's user avatar
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105 votes
Accepted

How could elves survive without any fat cell in their body?

Instead of fat, elves store energy as ethanol. Fats are the most dense form of food calories. Ethanol is a close second. From https://biology.stackexchange.com/questions/28511/what-is-the-most-...
Willk's user avatar
  • 305k
103 votes

How can a person be kept alive while being periodically drained of blood?

Open a blood bank and pay people for blood. People can give half a litre per donation and then go home. It's much cheaper than trying to keep them alive using machines. Build it in the poor areas ...
Thorne's user avatar
  • 47k
102 votes
Accepted

Suppose the Orcs are mammals, why is their skin green?

Flamingos are originally born grey but become pink due to eating brine shrimp, which have a natural dye called Canthaxanthin from their diet brine shrimp and blue-green algae. If an orc was like a ...
Fleon_'s user avatar
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102 votes
Accepted

Can a substance be more lethal in smaller doses?

Related to cmaster's solution: The "poison" is actually harmless A. The body converts A to B, also harmless. The body converts B to C, deadly. Once the A->B path has saturated you get an A->D path....
Loren Pechtel's user avatar
102 votes
Accepted

What mechanism can prevent super-healing heroes from accidentally budding?

Quorum sensing would be a very effective mechanism. This is a real life biological mechanism which is used by many small creatures like bacteria. Basically, it's a way of detecting how many similar ...
Cort Ammon's user avatar
  • 132k
102 votes

Why can't my huge trees be chopped down?

Underneath the outer cork-like layer of bark, the trees have a second foam-like layer. The cells of this layer are filled with a volatile liquid (in the chemistry sense - meaning it evaporates easily)...
Chronocidal's user avatar
  • 15.3k
101 votes
Accepted

For what reasons would an animal species NOT cross a *horizontal* land bridge?

One obvious answer is that the land bridge itself lacks food. Nothumans can cross the Bridge because they're smart and pack a lunch. Nothorses can't cross the Bridge because that region lacks fodder ...
elemtilas's user avatar
  • 40.6k
100 votes

How would trees communicate?

Plants already communicate, we simply ignore or are just now starting to discover most of the mechanisms they use. An African tree has been found capable of communicating with its neighbors to warn ...
L.Dutch's user avatar
  • 289k
96 votes

How many generations would it take until the noble and peasant classes become different species and cannot interbreed?

This speciation will never occur. Why? A condition Robert A. Heinlein once described as "common bastardy." People don't always keep their genes to themselves. Humans are well known as what I think ...
Zeiss Ikon's user avatar
  • 45.9k
93 votes
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How to replace a fictional element to the periodic table?

Unfortunately no, you can't replace an element of the periodic table because the ordering of the elements on the periodic table are based on the number protons found in the nucleus of the atom. ...
Giter's user avatar
  • 17.3k
93 votes

What would birds look like if they used buoyancy to fight gravity?

They would be round, because that's the best format for storing gas. They would also probably be drifters with little flight control. So...
The Square-Cube Law's user avatar
93 votes
Accepted

Would it be possible to have a GMO that produces chocolate?

Ok, so this seems pretty simple. There are three basic things that happen to turn cocoa beans into something reasonably approximating chocolate. 1: Fermentation Counterintuitively, the first step ...
Morris The Cat's user avatar
92 votes

Would a 'World Tree' be feasible in real life?

Water Basins If every 300ft or so the tree grew water basins to catch rain, (or maybe as a place to deposit water that it had already pulled up from below?) the higher parts could draw from these ...
Madcow's user avatar
  • 1,793
92 votes

What mechanism can prevent super-healing heroes from accidentally budding?

There is exactly one important cell - the Core The Core is what coordinates the super-healing. Every other cell is unimportant and will simply die when cut off from a "normal" body. They can't really ...
Secespitus's user avatar
  • 17.7k
92 votes

Is it harder for an intelligent octopus to live on land, or a human to live in space?

You can see octopodes crawl out of a tide pool and into a neighboring pool with little difficulty. octopodes have been known to crawl out of a tank in an aquarium and have the crab in the tank next ...
gwally's user avatar
  • 4,437
91 votes
Accepted

What kind of natural armor would stop bullets?

Mantis Shrimp Claws will do quite nicely. Carbon is extremely abundant on Earth's surface and presumably any other Earth-like planet that the author may be working on. Given the many forms that ...
Green's user avatar
  • 52.7k

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