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230

No As we currently understand physical chemistry, all possible elements are known below whatever the state of the art number is now (Oganesson - Element 118). The atomic number of an element (the number that determines which element it is) can only be an integer. It is, after all, the number of protons contained in the nucleus. Just like there are no ...


158

I'm sure this is outside of the range of temperatures you were interested in, but in the spirit of "truth is stranger than fiction," Helium-3 actually does this: The temperatures we are talking about are ridiculously small (fractions of degree above absolute zero), but note that the Solid region actually dips down around 0.3K. This means you can have a ...


145

Yes. Wikipedia has a good article on eternal flames which are fed by underground natural gas deposits. Those deposits can be immense, as we now know because we suck the gas out and use it for our hot water heaters. They can feed a flame a long time. The linked article notes several known to have burned for thousands of years. I propose you model your ...


121

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 of a kilogram or half a pound. The volume of a closed human mouth (a clear upper bound on the meaning of "a bite") is around 45-90 cm$^3$. Lembas bread is ...


112

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 fluids and then the filtered fluid with only the sugars are deposited onto your planet. The specimens themselves are made into powder to be consumed by other ...


106

Liquid Fluorine Vomit yellow in color Cryogenic liquid means it's boiling and smoking at room temperature. Melts/dissolves/burns almost everything "Glows" due to the burning of everything. Only an actual psychopath would use.


101

Why struggling for gold, which any king and even merchant of the medieval world has, when you can go for Aluminum, which no king yet has? Aluminum is shiny, like gold. Aluminum is malleable in thin foils, like gold. Aluminum, once passivated (i.e. covered by a thin layer of oxide), stops further oxidation. Gold is not oxidized at all, but no one will notice ...


100

Gold is one of the densest metals in existence. Only few metals and alloys are heavier, but they are not much easier to obtain, like iridium, osmium, neptunium and plutonium (!). If you use any lighter metal and try to make it look like gold you will be discovered and beheaded - the method of finding out density of alloys pretending to be gold was discovered ...


100

Immunity to Disease Your lunar citizens live in a perfect environment! They have all the food they need, they have recycling that, frankly, removes most bacteria from their lives. Atmosphere is constantly recycled, which includes scrubbing. Water, too, is recycled, scrubbed and clean for use. In fact, the colony has been disease-free for, well... ...


91

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. However, you may have another option. Carbon has 6 protons, always. Give it an extra neutron? Still carbon. Give it an extra electron? Still carbon. Give it an ...


87

The torch burns quicker. A lot quicker, but you won't get a violent explosion. Fire requires three things - heat, fuel, and oxygen. You've increased the oxygen, but you haven't increase the fuel, so all will happen is that the torch will burn out far faster - if it lasts for 10 minutes, it might not even last for one. The oxygen won't ignite itself. ...


85

In the books there is a bit more wiggle room : (Farewell to Lorien; last few pages) 'Cram', he [Gimli] said under his breath, as he broke off a crisp corner and nibbled at it. His expression quickly changed, and he ate all the rest of the cake with relish. 'No more, no more!' cried the elves laughing. You have eaten enough already for a long day's ...


81

I think ammonia would be a good gas to breathe in an ammonia world. There is a lot of it handy, I would imagine. As opposed to N2 which is sort of an ice queen and reluctant to mix it up with other molecules, NH3 has 3 promiscuous hydrogens hanging off, ready to get busy. And NH3 protonates easily to NH4+, opening a whole other range or repertoires. ...


78

Unfortunately, no matter how much pure gold you add to your mass, you will never end up with a star. The reason for this is that fusing gold is an endothermic process, meaning that it requires energy, rather than releasing it. In fact, all elements with an atomic mass greater than or equal to that of iron consume energy upon fusing, rather than releasing ...


77

Use Iron's allotropic forms Iron has a wide variety of allotropes. Two interesting ones are austenite, with atoms aligned face-centered cubic (FCC) and hexaferrum, where the atoms align in a hexagonal close packed (HCP) form. Here is the phase chart for iron: Both Austenite and Hexaferrum are denser than the Ferrite that they will phase transition into at ...


76

No no no no no no no no no. Bad idea. Chlorine trifluoride is one of the most horrifying substances on Earth. Sure, it can kill people and destroy equipment. But it can also kill the people trying to use it as a weapon. It's difficult to contain and nearly impossible to fight if it starts a fire, and produces extremely toxic byproducts when it reacts with ...


74

Option 1: Island of Stability As @AlexP mentioned in a comment, there is a theory called the Island of Stability, that states that there may be a window (or windows) in the super-heavy elements which are stable. The current expected window is in the 120s, but you could have another window; say the 180s or 230s (or whatever). The elements might occur ...


71

Killing the monster with VX nerve gas or an overdose of fentanyl or cyanide muffins seems kind of anticlimactic. You can kill anything with that stuff. The whole thing about werewolves is that silver is not predictably a super killer or especially bad for anything else. It is a secret special Achilles heel for werewolves. Except not so secret because it ...


65

Almost all currently used explosives have an oxidant (or it's equivalent) "built-in". They already work in space, under water, etc just as well. Let's look at thermite (which is not an explosive, but incendiary, but it's easy to understand) as an example. It consists of pure aluminium and iron oxide. The aluminium burns by taking the oxygen from iron oxide,...


63

Easy Peasy. Fusion reactors. The primary challenge involved with fusion power is maintaining containment, which is a big challenge given the pressures and temperatures involved. Not only will the neutrons deposit energy in the blanket material, but their impact will convert atoms in the wall and blanket into radioactive forms. Materials will be ...


60

Yes. They plant a forest of trees ( a renewable resource) to be used only for the holy flame. Faithful can also come and throw offerings (wood, coal, hay, etc) into the fire. They could also carve prayers into the logs that will be put into the fire.


59

Bloody Paint Why bother turning it into some kind of structural material? Just use it as the paint on literally every surface with this girl's blood. It'll be an awful color when it dries, but if dried blood still works, use it as paint. Walls, floor, ceiling, the bars on every cell. The stuff will be everywhere, radiating its effect from every direction, ...


59

Dissolving folks quickly is hard work Most acids aren't going to eat through you (or your average door) quickly -- while they denature proteins and dissolve metals, they don't have the oxidizing power to dissolve someone movie-style, and won't eat a doorknob faster than a drill bit. Even strong oxidizing acids can be sluggish by themselves under normal ...


57

Water ok, beer. Watery beer. An explosion occurs when matter changes so as to occupy more volume. We are used to the explosions where a solid or liquid suddenly changes into a gas, which takes up loads more volume. When water freezes, the solid form takes up more volume than the liquid. If confined in a space which cannot deform, the expanding ice can ...


56

Heat drives a compound out of solution Heat can drive moisture out of a substance. If some substance mixed with water is a very viscous fluid, then driving the water out with heat could leave you with a solid. According to various pottery blogs, moist clay is about 30% water, all of which is driven out in the process of firing. A viscous mixture in ...


56

This star would not fuse gold. Fusion reactions producing elements beyond zinc-60 are not energetically favorable; they are endothermic, and so consume energy. Several elements heavier than iron are formed through this fusion chain and subsequent decay (cobalt, nickel, copper and zinc), but these are unstable and decay back to iron, meaning that iron is ...


55

Apollo Fire and Wick Effect I generally agree with Halfthawed, but I had some additional thoughts on the matter. There is one well known and documented incident with fire and people in a pure oxygen atmosphere: the 1968 Apollo 1 accident. The fanatic overexaggerated fear of a pure oxygen atmosphere is rooted in the horrible 1968 Apollo 1 accident where ...


54

Almost, but generally no1 There are no such metal, alloy or pure element which does this within a reasonable temperature-pressure range2; but there are materials which can behave this way. Why does stuff generally melt when heated and not when cooled down?3 All matter in our universe follow the bureaucracy founded within thermodynamics and, as part of that,...


54

Chlorine Trifluoride as a Space Weapon? Not really. Indirectly useful? Yes, for disinformation. Convince the enemy that you've found a way to effectively weaponise it. Contrive for them to "find" semi-destroyed plans for a weapon prototype in a way that they can't help but believe is real. (A courier ship on a desperate run carrying "plans" fights a ...


53

The nature of your question makes it sound like the fire was already there, that these people found it rather than lit it. In which case Will's answer is perfect (and you could easily see why a primitive people could be very impressed by something like that and consider it spiritually important). But as someone who works with wood fuelled fires on a regular ...


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