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252 votes
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Would somebody from the middle ages be able to identify an atomic / nuclear bomb?

Let's try to do this. (They told you it can't be done. They're right. Realistically, it can't. So, disclaimer: I'm going to employ industrial quantities of high-grade Improbability). Notes I had to ...
LSerni's user avatar
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141 votes
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Can stone be "recycled" by melting and cooling it?

It depends on your rock. Rocks like Granite, with large crystal sizes, are the result of VERY slow cooling and crystallization. So although in theory you could remelt and recrystallize this kind of ...
Andrew Dodds's user avatar
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125 votes
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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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121 votes
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Why would any interstellar starship still bother with streamline body design?

One reason that might play a larger part than you'd think is actually aesthetics. Sure, a big ugly ball of components is the cheapest option now, but will it net you any sponsors for your next ...
Joe Bloggs's user avatar
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110 votes

How to make a metal with extraordinary property worthless?

It turns out to be radioactive. It's light, it's beautiful, it's strong. ... but anyone who carries or wears the metal for more than a very short period of time eventually gets sick. This wasn't known ...
Murphy's user avatar
  • 26.4k
104 votes

Speedrun to the moon in one lifetime?

Impossible This is an extension of, or complement to, L.Dutch's answer, which was first. I upvoted it. So should you. I'm fond of reminding people that 99.99% of the technology we enjoy today was ...
JBH's user avatar
  • 125k
96 votes

Everyday tasks on a space ship

...once they reach a planet, they do research. Nope. They're doing research all the time. That's their full-time employment. Aside from the usual time off, it's nonstop research. Once they reach ...
Cyn's user avatar
  • 20.4k
86 votes

How to make a metal with extraordinary property worthless?

Titanium is actually a fascinating example standing by itself, because it's not that hard to find (it was identified as an element before 1800, and is the ninth-most abundant element in Earth's crust) ...
Cadence's user avatar
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85 votes
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What happens when a moving vehicle loses all its kinetic energy at once

This is exactly what used to happen to cars before Volvo introduced Crash Test Dummies When I was growing up, many of my parents' friends were constantly bemoaning the fact that cars 'just weren't ...
Tim B   II's user avatar
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85 votes

How many cows would you need to drop on Mars to successfully terraform it?

1 Quintillion, or 1x 1018 This is based on a few assumptions of course, and there is a big caveat on it as well. Before you start - you need to ensure that you put a magnetic field in place. Without ...
Tim B   II's user avatar
  • 54.1k
82 votes

Would somebody from the middle ages be able to identify an atomic / nuclear bomb?

For your reference: some years ago in Brazil a scrap thief, while salvaging through the remnants of a hospital, found a piece of material which emitted a nice glowing blue light. He was smart enough ...
L.Dutch's user avatar
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81 votes

How plausible is a 'tilted axis' planet with a "south pole" constantly facing toward its star?

Utterly impossible. You simply cannot have one pole of a rotating planet always oriented the same way towards the sun, for the simple reason that the pole always points in the same direction in space,...
Logan R. Kearsley's user avatar
80 votes

Speedrun to the moon in one lifetime?

I don't think it's feasible. First of all, for anything they need, they might know what they need to build, but they have no way to reach the place where the raw materials are located. E.g. Jim: &...
L.Dutch's user avatar
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71 votes

Why would any interstellar starship still bother with streamline body design?

Space isn't a pure vacuum. There's still bits of rock and other debris floating around. Do you really want masses impacting your ship at fractions of light speed? Streamlined designs would have ...
nzaman's user avatar
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70 votes
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How to be hidden from world for a year

If you're a billionaire and already under the focus of the TLA Agencies, best how to disappear for a year is... not to disappear. If you'd suddenly disappear from today to tomorrow a dozen of alerts ...
Alexander von Wernherr's user avatar
70 votes

Why would any interstellar starship still bother with streamline body design?

Radiation Hazards, or why I learned to stop worrying and build my ships like skyscrapers. One reason among many is to shield the crew from Radiation. Not incident interstellar radiation, though - ...
UIDAlexD's user avatar
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70 votes
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The Heisenberg Uncertainty Ray - A Hyper-Scanning Doomsday Weapon

I am not sure where the energy would come from for this It would come from the scanner itself. In order to make extremely-high-precision scans, the scanner itself has to direct considerable energy ...
Dave Sherohman's user avatar
69 votes
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Why combat machines in this world are colorful

It is Urban Camouflage The International Style of Architecture, well known for is hundreds of different shades of greys, off-white, near-black, and beige was popular throughout most of the 20th ...
Nosajimiki's user avatar
  • 95.8k
66 votes

What possible scientific reasons could there be for a vampire to only be killable via wooden stake to the heart?

It's due to the nature of vampires, and their regenerative state. If a metal or other non-organic substance is thrust into their body then over time their regenerative abilities will push it out. Even ...
Tim B's user avatar
  • 77.1k
66 votes

Can an alien society believe that their star system is the universe?

According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Bo├Âtes void, we wouldn't have known there were other galaxies until the 1960s."...
Vashu's user avatar
  • 4,210
65 votes
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Does knowing a technology exists make it develop faster?

I would think so. Innovation is probably the hardest bit and duplication is much easier. We see it with computers all the time now. Some small company comes up with a new idea that is "obvious" and ...
dmoonfire's user avatar
  • 1,191
65 votes
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Would using carbon dioxide as fuel work to reduce the greenhouse effect?

It is technically possible to burn carbon dioxide, but not in a practical way. The reason burning carbon produces energy is that the total potential energy of carbon and oxygen is minimized by the CO2 ...
Cadence's user avatar
  • 38.5k
65 votes

Why combat machines in this world are colorful

Fighting enemies who see differently These days deer hunters tend to wear vests that are highly visible to other hunters (in order to reduce the chance of being shot accidentally) but are effective ...
KerrAvon2055's user avatar
  • 27.8k
64 votes
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What possible scientific reasons could there be for a vampire to only be killable via wooden stake to the heart?

Now, a few answerers have claimed that the stake need not be wooden. While this may be true in the traditional vampiric lore, we exist only to answer the specific question here. Why Wood Vampire ...
Dent7777's user avatar
  • 2,837
63 votes
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A food item only made possible by time-freezing storage?

There is a huge number of delicious fruits that are rarely eaten outside the regions they grow because they either don't transport well or go bad way too fast or both. Examples Cherimoya : a fruit ...
John's user avatar
  • 81.5k
60 votes

Why does my futuristic society want transparent iPads and computer monitors?

Because Apple's marketing department says you want them and (by pure coincidence) so do all the ads and influencers on the internet.
Mon's user avatar
  • 17.4k
58 votes
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Learning new physics from a superhero

Test her limits. Can she move more than one thing at once? If so, how many? How large of a thing can she move, both by weight and by volume? Is there a minimum size an object has to be, or could she ...
Ryan_L's user avatar
  • 13.8k
55 votes

Speedrun to the moon in one lifetime?

It can't be done. There's a famous phrase in project management, "Nine women cannot make a baby in one month." This is one of those cases where you just can't parallelize enough. The ...
Cort Ammon's user avatar
  • 132k
54 votes
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Spaceflight without transistors and nuclear power - how to bend the history of physics?

Move the space race earlier. 1931. There are not transistors or nuclear power because neither has been developed. But space is in reach. from http://www.computerhistory.org/revolution/calculators/...
Willk's user avatar
  • 305k
54 votes

The Heisenberg Uncertainty Ray - A Hyper-Scanning Doomsday Weapon

This "weapon" has already been built. It's called the European X-Ray Free Electron Laser (XFEL), and it's used for super-accurate imaging of molecules. Point is, whenever the XFEL hits a target ...
cmaster - reinstate monica's user avatar

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