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 ...
- 303k
214
votes
Accepted
If everyone in the world disappeared except 35 random people, how long would it take for one of them to realize they're not alone?
Assuming that it's purely random, let's consider where these people would probably be. Taking the percentage of the population each country represents, we get:
China: 18.2% = 6.37 people
India: 17.5% ...
- 1,713
201
votes
If everyone in the world disappeared except 35 random people, how long would it take for one of them to realize they're not alone?
It's HF radio, or nothing
The odds of anyone meeting again are almost exactly equal to the odds of at least two being either radio hams, or able to learn the skills from books.
The population ...
- 3,165
143
votes
A 40km diameter alien saucer is floating 2km above the ocean for a long time. What are the effects on the sea ecosytem below?
The ocean is a dynamic and very large place, so it's unlikely to have many large-scale effects unless humans overreact. I'll focus on the local, immediate effects of this saucer from a physical, ...
- 12.1k
129
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 ...
- 17k
119
votes
Accepted
Is it possible to kill all life on Earth?
Not with the time constraint given.
Let's start with the most destructive thing we've got: nukes. There are about 15,000 nukes worldwide, of varying yields. Sources:
World Nuclear Weapon Stockpile, ...
- 131k
113
votes
Accepted
Building a road to escape Earth's gravity by making a pyramid on Antartica
The maximum height a mountain can have on Earth is a tad more than what Mount Everest is high. This is due to the fact that when you increase the height of the structure, you are also increasing the ...
- 263k
109
votes
Accepted
Reasons why healthy people would intentionally want to get infected?
Natural Vaccination.
Read about how Cowpox was used to vaccinate against Smallpox, this is our IRL first instance of vaccination against a disease.
The word “vaccination,” coined by Jenner in 1796,...
- 33.1k
94
votes
Accepted
How long would it take until we realise that people stopped dying from natural causes?
One day. Few at most.
In most modern countries death reports are passed to government agency on daily basis. Clerk responsible for them would be surprised that there are none in his area. He will ...
- 33k
93
votes
Would a squad of soldiers who can shapeshift into T. Rexes be useful in a modern battle?
I can imagine battlefield logistics would be much easier. One of the most dangerous and common tasks for infantry is shuttling supplies back and forth between the front lines and the forward camp. If ...
- 1,155
93
votes
Accepted
If all natural sources of oxygen production stop, how long do we have?
All the info we need to calculate this is in the wiki for the oxygen cycle. The atmosphere gains and loses about the same amount of oxygen each year: 3 $\times$ 1014 kg. It also currently holds 1.087 $...
- 131k
85
votes
Accepted
What would happen if the Earth struck a tiny but immovable object
As @Thucydides mentioned, researchers posited a similar magnitude of impact and thought they had found evidence for it, though they later retracted their findings they did calculate the potential ...
- 116k
83
votes
How can a colony of teleporters make the most money while keeping their teleportation a secret?
First of all they should only teleport things, not people. People talk. Otherwise, they're in the shipping business.
They should use their teleportation ability to mimic real world transportation so ...
- 4,865
83
votes
Building a road to escape Earth's gravity by making a pyramid on Antartica
You've already accepted an answer, but aside from the structural issues (and the sheer mindboggling amount of energy it would take to pump all that water up that high), there's another ...
- 67.3k
83
votes
Where on Earth is it easiest to survive in the wilderness?
As a native I'm definitely biased here, but Ireland is actually a pretty good bet.
Especially towards the West, Ireland has actually seen a decline in rural population. You can genuinely walk for ...
- 1,557
81
votes
What are the effects of slicing the Earth in half with a particle beam?
All the people who said "We all die!" are correct with good answers, but for most people it won't be the earthquakes that kill them -- they'll already be dead.
The leakage from the radiation beam ...
- 14.2k
80
votes
Reasons why healthy people would intentionally want to get infected?
Because some self-proclaimed health guru claims that it's good for you to have that disease.
The miracle-virus causes your body to absorb free cosmic energies. Your constantly raising body ...
- 48k
80
votes
Accepted
How can a colony of teleporters make the most money while keeping their teleportation a secret?
Think Small
Instead of moving items very large distances; why not move them small distances; it's not like you get paid per mile. You could almost entirely remove the equipment cost and drastically ...
- 1,176
77
votes
Can a human survive acceleration from 0 km/h to 310 km/h, and then back down to 0 km/h, all in 500 meters?
310 Km/h is 86 m/s. This means that on your 250 meters track (for acceleration), you'll have a mean speed of 43 m/s, meaning that you'll reach your 250m in 5.81 seconds. Now, 86 m/s reached in 5.81 s ...
- 5,281
76
votes
Accepted
How to tell if the entire Earth is just a copy?
Even the satellites and every sensors on Earth were returned to that exact moment and this only affects the entire region of space up to orbit of moon (...)
Everything above the Moon will seem to ...
- 131k
70
votes
Could we reach the earth's core using today's nuclear arsenal?
No.
On this scale, the Earth is not solid and rigid. It's more like extremely hot jello, with a thin and weak crust, a layer of hot floppy jello, the "mantle", a liquid outer core (actually ...
- 22.2k
69
votes
Accepted
Would evolution happen the same exact way if Earth restarted?
The first thing that it's important to understand is that evolution is a by-product of natural selection, not the driver of it. That is to say, every change introduced by DNA combinations and ...
- 53.9k
67
votes
Accepted
If an FTL spacecraft entered Earth orbit, how long would it take for humans to build a FTL spacecraft?
It depends on how far from the current production possibilities frontier this technology is. There are several possibilities, depending on the technology gap:
It is like the Apollo Moon mission to ...
- 59.7k
66
votes
Is it possible to kill all life on Earth?
No.
Most of the preceding responses have overlooked one relatively-recently identified home for life on the planet; within the crust itself. Researchers have found bacteria up to 4 kilometers down in ...
- 21.1k
66
votes
Accepted
Best place on Earth to fake being on a distant planet?
The problem your going to have in any open sky area however, is the familiarity of the moon and constellations - a dead giveaway that your still on earth.
To that end, I'd suggest the best place for ...
- 675
66
votes
Dungeons for Real: 1. The Bottomless Pit
Indoor skydiving
Indoor skydiving simulators are popular and not particularly difficult to build.
A person who falls into a "bottomless pit" would feel like they're falling faster and ...
- 42.1k
61
votes
Would evolution happen the same exact way if Earth restarted?
No, but...
If you restart evolution, you would end up with new species. But some of their features may be very similar to what we know in our world.
The Nobel Prize winner Jacques Monod said that ...
- 1,188
60
votes
Best place on Earth to fake being on a distant planet?
This place cannot have any obvious life forms. Nothing too complex
(Small microbial creatures are fine)
No humans for at least a few hundred miles, and no signs of their presence.
Must be ...
- 263k
Only top scored, non community-wiki answers of a minimum length are eligible