L.Dutch
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Could two planets follow the same orbit and never "see" each other?
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50 votes

I assumed, based on the limited knowledge I have on the subject, that all star systems have ellipsoidal orbits (the star being in one of the two focal points) just like our own You are right, this is ...

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Why are my caves warm with nobody heating them?
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49 votes

Geothermal heat. It's well established that the more in depth one goes, the higher the temperature is. It It is called geothermal gradient Geothermal gradient is the rate of increasing ...

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Would it be possible for hunter gatherers to accidentally colonize an exoplanet, from an asteroid knocking a rock containing a cave into space?
48 votes

The rocks that ceiled the hunter gathers in the cave for many generations are ejected from the entrance to the cave when the rock crashes into the planet, allowing the hunter gatherers to leave the ...

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A Society Built Around Theft?
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48 votes

A similar system was used in the spartan agoge Boys were intentionally underfed to encourage them to steal food for themselves; however, they were severely punished if caught. This was part of the ...

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How could a self contained organic body propel itself in space
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48 votes

If you don't want or can't afford ejecting matter, you are left with solar sail: since photons carry momentum, reflecting photons can allow you to harvest that momentum and use it to move. Expand ...

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What could prevent players from leaving an island?
48 votes

Have you seen Cast Away? When the main character attempts his first escape from the island on a self built raft, he fails because outside of the lagoon the ocean is fierce and smashes the poorly ...

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How useful would a hydroelectric power plant be in the post-apocalypse world?
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48 votes

On September 28 2003, Italy experienced a nation wide black out. After three hours, energy was restored in northern regions. Electricity was restored gradually in most places, and in most cities ...

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Would Moore's Law apply to mechanical computers?
48 votes

First of all, Moore's law is not a law of physics like Newton's law of gravity. It is just an empirical evidence that has held until now, in a quite surprising way. While we have been able so far to ...

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Reasons a fictitious metal is really hard to refine?
47 votes

The metal can be either very reactive, as you stated, or it can have a very high melting point, making it unpractical to use smelting based refinement techniques. Think for example of tungsten which ...

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Can there be a single technologically advanced nation, in a continent full of non-technologically advanced nations?
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47 votes

While the Roman Empire had the technological knowledge to build aqueducts, roads and buildings like the Pantheon, in the same continent there were populations which were not far herding sheep in ...

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Can a dedicated amateur astronomer spot a rogue asteroid?
47 votes

The sky is too big to let only professional astronomers look at it. Consider that professional telescopes have limited time windows for specific researches. And if you want to spot potential hazards ...

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How can you build cities without cement?
47 votes

During the roman empire they didn't know modern cement, but they built "small thingy" like the Pantheon by using pozzolan, which is basically volcanic ash. That would be a good material to use.

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Could negative kelvin be achieved?
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46 votes

To use scientifically correct terms: forget about it. First reason comes from the definition of temperature. To explain it in layman terms, the temperature measures how much the molecule of matter ...

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The students have blown up the school using stuff that looks like snow. How?
45 votes

DISCLAIMER: DON'T TRY THIS AT HOME, SCHOOL OR WHEREVER YOUR YOUNG AGE TAKES YOU You are looking for a dust explosions, which can be caused by grain, flour, starch, sugar, powdered milk, cocoa, ...

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What should be done with the carbon when using magic to get oxygen from carbon dioxide?
45 votes

Use the carbon to add new activated carbon to the mask filter. Though ineffective against toxic gases, active carbon is good at capturing other contaminants. Activated carbon, also called activated ...

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

•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, ...

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AIDS vs Great Plague in medieval period
45 votes

AIDS is a sexually transmitted disease, and we have the chance of another STD which appeared out of nowhere around those times (actually about a century later): syphilis. When it was imported from ...

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Why would a language spoken by humans entirely lack bilabials?
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44 votes

When I was a kid one of the game we played with my friends when we were in the sea was to talk underwater and have the other understand what we were saying. If we were wearing a scuba mask and the ...

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Would coating a space ship in liquid nitrogen mask its thermal signature?
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44 votes

If your aim is to use liquid nitrogen to mask heat, it will be just a temporary mitigation. The heat from the ship will cause the liquid nitrogen to heat up and evaporate in the vacuum of space. If ...

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What is the most reasonable way for non-binary computers to have become standard?
44 votes

Non binary computers, in particular ternary computers, have been built in the past (emphasis mine). One early calculating machine, built by Thomas Fowler entirely from wood in 1840, operated in ...

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Could there be a helium based life form somewhere in the universe?
44 votes

Helium is a noble gas. This means its reactivity toward other elements is practically null, so small that even its molecules are mono-atomic. Life as we know it is based on several molecules formed ...

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Consequences of an altered square cube law
43 votes

Square-cube law is a consequence of us living in a space with 3 spatial dimension, is not a whim made up by bored biologists. when doubling size it instead only doubles its mass You have created a 1 ...

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Why would humans want "mindless" human clones and even be legal?
43 votes

The mindless clones are used as "friends with benefits" by their owners, and for those kind of benefits no android or robot can compete with the real thing. Of course this is not something ...

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Let’s say a 1 ton (US) sphere of tungsten moving at 99.99% the speed of light hits earth, what happens? As specific as possible
43 votes

According to WolphramAlpha, the relativistic kinetic energy of such a bullet would be $6.265 \cdot 10^{21} \ \mathrm J$, or 1.5 million megatons. The gravitational binding energy of Earth is $2 \cdot ...

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How can I explain a one-shot, slow-to-reload laser sidearm?
43 votes

You can use a chemical laser A chemical laser is a laser that obtains its energy from a chemical reaction. Chemical lasers can reach continuous wave output with power reaching to megawatt levels. ...

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Living in a Giant Swamp - Construction
43 votes

Such a city has been already built in reality, and it was even the capital of an empire: Venice The buildings of Venice are constructed on closely spaced wooden piles. Most of these piles are still ...

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Could agriculture still be developed by intelligent species that lack the concept of past and future?
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42 votes

If they have no sense of past or future, they live in a continuous present, answering the stimuli they are getting right now: pain? move away! hunger? eat! Thirst? drink. Nothing more than an amoeba. ...

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Fart & Furious: flatulence as acceleration booster possible?
42 votes

I don't think it is viable. If you want to propel the athlete of mass m to certain velocity v starting from rest, you need to provide a momentum $P = m_a \cdot \delta v_a$. The same momentum has to ...

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Would Vantablack hide planes from radar?
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42 votes

Radar operates at about 50 cm wavelength. Vantablack reflectivity spectrum shows 2% reflectivity at 25 micron, and rising. So my answer would be no. There are special paintings developed to ...

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Is the concept of a biometric smart gun that will detonate when anyone besides its owner touches the weapon unrealistic?
41 votes

There are cases where you want someone to handle the gun without firing it. Just to name a few: the legitimate holder has lost the gun and someone returns it to them the legitimate holder is dead but ...

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