# In what kind of element should aliens pay us? [closed]

I have a situation where aliens need to pay Earth for something, they don't want to share their technology but they offer any naturally occurring chemical element.

Assuming that we'll get 10,000 tons, what kind of element makes the most sense to ask for? Precious metals, uranium or something else?

Answers

The payment is for the Earth as a whole and goes through UN, they will deliver to whatever address Ban Ki-moon decides.

I'm asking what is the most valuable element for Earth. Something that would be useful for us, but either we don't have it on the Earth or it's very hard to extract it.

I want to keep things simple so single chemical element in whichever allotrope or isotope we want, as long as it's occurring naturally in our galaxy. No exotic matter, anti matter, neutronium, transuranic elements ...

## closed as too broad by Mołot, John Dallman, Hohmannfan, TrEs-2b, AndreiROMOct 31 '16 at 23:44

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• They can't just give stuff to Earth. They have to give it to whatever individual, group, or organization is making a deal with them. The answer will depend a lot on who that is. Elon Musk? Kim Jong Un? – MissMonicaE Oct 31 '16 at 15:07
• Are you basically asking which element is the most valuable per weight? If not, you may want to specify what your question is. Abd btw: Welcome to worldbuilding. You may want to take a minute and have a look at the tour and help center – Burki Oct 31 '16 at 15:09
• Does it all have to be a a single element? Does it have to be a pure element? For example could we ask for compounds? Do we get a say in the form of the materials? 10,000 tons of diamond is very different from 10000 tons of graphite. If humans can show we can already manufacture some type of crystal or compound or machine would they be willing to simply duplicate it until there's 10,000 tons of it? – Murphy Oct 31 '16 at 15:11
• @Bloc97 Please don't post answers as comments, which cannot be voted on properly. – a CVn Oct 31 '16 at 15:16
• Obligatory xkcd. Covers some naturally occurring substances along with some artificial/technological ones, but still interesting and might inspire some thoughts. – Cody Oct 31 '16 at 21:32

## 7 Answers

Graphene would be a very nice payment - it has a huge range of uses, but it's still difficult and time consuming to produce. 10 kilotons of the stuff would be a massive boon.

Helium-3 would also be a very, very nice payment. 15-20 tons of Helium-3 in fusion reactors could power the United States for a year - 10,000 tons of the stuff would keep the US going for half a millennium.

• Unless you're Fisker automotive, who claim to have a good graphine production method... fiskerinc.com – PipperChip Oct 31 '16 at 15:25
• Why does it have to be the US, can't we power something else? – John Keates Oct 31 '16 at 17:29
• @JohnKeates We could power anything we wanted - the US was just used as an example of an energy-hungry nation. – Werrf Oct 31 '16 at 17:33
• @brichins Somewhere over my garden! – Avrohom Yisroel Oct 31 '16 at 22:51
• @brichins we should probably keep it in a sun-sized box as a spare for when our current sun is done being sunny. – John Keates Oct 31 '16 at 23:00

I'd make a case for Neodymium. It has become indispensable for use as magnets in many electronic devices such as hard drives and smart phones, and there are already concerns about whether we have enough of it.

Iridium is an extremely hard, dense and stable element – the most corrosion-resistant metal known, and among the most temperature-enduring ones. It is also a good catalyst. It could conceivably push some technologies a good way beyond what's feasible today, if iridium were available in quantity – but this metal is much rarer than even platinum. Demand has risen considerably since 2000, and I think it would rise a lot more if the stuff were somewhat cheaply available for a while.

This would furthermore not be quite as unlikely as the other suggestions here – iridium is actually not so rare in the universe (as antimatter) or short-lived (as radon), it's just not available for us on earth because almost all of it has sunken into the core in earth's early life.

Abundance is actually not the only hurdle in adoption of iridium – the extreme resilence of this metal obviously also make it very difficult to work with. Nevertheless, I think it is a good candidate.

• For similar reasons, rhenium would also be a candidate. It's apparently not quite as hard and dense, but better workable and great for making alloys. Rhenium is actually more expensive than iridium at the moment; not sure whether it would in the long-term be more useful to Earth. – leftaroundabout Oct 31 '16 at 22:28

For scientific study, there are a few substances that would be immensely valuable to science because they are extremely rare/non-existent on the surface, and with half-lives of just a few minutes/seconds/fractions of a second in many cases. Acquiring a huge sample is impractical, so we know little about them. Using the aliens to get a huge sample would help advance science some. Examples are astatine, radon, and francium.

If the United States is getting part of the supply, it might appreciate a huge boost in copper, so the cost of producing a penny can fall below 1 cent again, saving a bunch of money each year. Also its useful in electronics and stuff, but think of all the pennies we can make!

Or maybe they could take stuff instead? It'd help climate change if they could just take a huge amount of CO2 from our atmosphere using their advanced tech, which would help slow global warming a little. That might actually be the most beneficial option to humanity. I don't know if 10k tons would be enough to make a huge difference though. Since annual emissions are in gigatons, I suspect not.. However, maybe they could take 10k tons of spent nuclear fuel instead. According to this, we produce about 2,000 tons of nuclear fuel per year. It'd really help the nuclear waste storage problem if they could take 5 years worth of radioactive waste off the surface and throw it into the Sun for us.

• Just please don't ship 10k tons of astatine in one delivery... that would almost rival the antimatter in terms of destructive potential. – leftaroundabout Oct 31 '16 at 22:04
• Funny follow up idea: it took many years for the physicists at CERN to find the Higgs Boson. Can we just order 10k tons of them from the aliens, just to be super sure of our discovery? – Cody Oct 31 '16 at 22:14
• The OP wants an element. Higgs bosons aren't an element. – a4android Nov 1 '16 at 10:44

# Antimatter

This would be the ultimate fantasy for any world power. It can be used for both: extremely cheap (almost free) electrical energy for everyone for the next whole century for all people of Earth. It can also be used as the ultimate weapon of mass destruction. Imagine, just 100 grams of antimatter would annihilate with matter in a blast which would be dozens of times more powerful than the atomic bombs dropped on Japan.

Basically, antimatter particles are the same as matter, only with opposite electrical charge as the normal matter. It is estimated that at the origin of the universe, almost equal amounts of matter and antimatter would have formed. However, all the universe we can see, is made of matter. Where did all the antimatter go? Nobody knows.

• Unfortunately, we have no way to contain, control, or use antimatter. The best we've been able to do so far is preserve a single atom of antihydrogen for 17 minutes. I'd rather not have 10 kilotons of the stuff sitting around when minute 18 rolls around... – Werrf Oct 31 '16 at 17:47
• @Werrf: Considering that the aliens are giving the stuff to us as a payment of something means that they are handing it over to us in a form which is safe to transport. So that the containment/control is already covered. As for the usage, well ... all we have to do is to release extremely little amounts of the stuff in fusion chambers where it would annihilate with matter to produce very high temperatures which would be used to convert water into steam and rotate the giant rotors and generate electricity. – Youstay Igo Oct 31 '16 at 21:08
• @YoustayIgo Safe for them to transport doesn't mean safe or accessible for us actually use. Unless the aliens provide accompanying tech for precise control, separation, and usage (which would be well beyond the scope indicated by the OP), a large solid block of antimatter in an alien cargo crate is worse than useless - it's large-scale unexploded munitions. – brichins Oct 31 '16 at 22:10
• I would say mercury antimatter, or Fe antimatter. Some of metals just for ease to use and manipulation, probably something with high melting point. Also as then right away to slice the ting in chunks 1kg or something like that, just to be easier for use(maybe) in future. On stable orbit for sure, I mean in micro gravity. – MolbOrg Nov 1 '16 at 5:16
• The OP excluded antimatter. The element has to be naturally occurring too. – a4android Nov 1 '16 at 10:43

There's a couple of really good answers we know.

1: Fissile plutonium.
2: Fissile thorium.
3: Titanium.


They could pay us in enriched uranium but uranium < plutonium and more expensive to get so why bother.

1 and 2 are a lot of energy available really easily, while 3 is a metal that is worth a lot and won't lose value quickly by becoming more common because it has so many uses.

10,000 tons is a lot. Up till now, the world managed to dig up

Adding a sizeable share (1/17th for gold, 1/6th of annual production for Uranium) to the market pretty much invalidates the value that is put upon it for the next generations.

However, there are materials that wouldn't wreak havoc on the world economy in that large quantities. Among them are iron alloys (1,599.5 million tons / year!), where the effect would be negligible.

If you want to keep the world economy intact: take something that we produce arbitrary amounts already.

• On the one hand adding 10K tons of something would devalue it making existing mining operations less economic, on the other hand that lower price allows it to be used for things it otherwise wouldn't be economic to use it for. ~doubling the worlds availible platinum would make technology that requires platinum much cheaper and more economic to produce. So it doesn't seem accurate to say it would wreck the economy. – Murphy Oct 31 '16 at 16:21
• "Did you stop to think about what would happen to the poor gold miners?" – user25818 Oct 31 '16 at 18:34
• @Trish If it isn't valuable why asking for it, we might as well give them a freebie. Also isn't ecological damage caused by mining worth something. – slobodan.blazeski Oct 31 '16 at 20:05
• The whole point of a transaction is that both parties are getting something valuable in return. But you are actually suggesting that they ask for something relatively worthless in return. Why would anyone agree to such a transaction? How would that make any sense? – J Doe Oct 31 '16 at 20:33
• Gold and uranium are reasonable choices. Gold is overrated as valuable metal, however, its physical properties make it an extremely useful metal. Not that I'm a fan of nuclear power, but if the 10 k tons of uranium was isotope 235 this provides more than enough to run fission reactors for, perhaps, millennia. Perhaps, gallium which is used in superconductor circuitry. The element should be useful without being too economically disruptive. – a4android Nov 1 '16 at 10:42