The question and answer are both quite fascinating. But I think they hint at something potentially even more interesting: To figure out that they needed to coat visors with gold, without doing it by trial-and-error and frying a few retinas in the process, the level of planning and attention to detail in the early days of NASA must have been phenomenal. I'd love to know more about how they knew they had asked all the right questions.
If you can dig up a copy of the 1962 book "Space Medicine" by U. Slager, it's really interesting. It makes you realize how many questions they needed to answer experimentally before going into space. For example, how much acceleration can someone withstand. How much vibration and tumbling. Minimum and maximum survivable temperatures. How long can you be exposed to a vacuum. This was the era of putting people on rocket sleds to see what happens ( http://en.wikipedia.org/wiki/John_Stapp ). My favorite factoid from that book is that guppies can tolerate 10000G for 30 sec. It also describes a guy who survived 482 degrees F for 4 minutes.
I messed up °F/°C and it was "only" 250°F. I don't have the book "Space Medicine" available, but I found a different reference† explaining that it was Dr. Charles Blagden and other researchers in 1774 who went into a room heated above 250°F and cooked steak and eggs in there, proving the importance of perspiration in maintaining body temperature. It has to be dry heat; if there is humidity, the tolerable temperature is much lower. The original paper ‡ is also online; in order to read it, note that "ſ" is a "long s", not a "f".
For people of the world, that's about 121°C. BTW, I've been in a sauna in Sweden where the thermometer displayed 100°C. The women sauna, according to my mother, was only 96°C.
Behold the Bioastronautics Data Book [1], featuring sections like "Generation and Composition of Flatus" [2] and "Buttock Areas and Thigh Dimensions" [3] and captions that start "Data obtained on two subjects in ejection seat attached to arm of underwater centrifuge..." [4]
Why do you believe they didn't fry a few retinas? They could've used animals for experimentation - I'm sure a lot of rats and monkeys gave their lives for the goal...
This just reminds me how horribly stifling it is to the entirety of science that so many people love hoarding bricks of gold in underground vaults rather than use it for productive purposes. Besides the maliability and corrosion resistance mentioned in the article, it is also a strong conductor, and very good at heat transfer.
It has so many practical useful purposes besides rotting in a bank vault. But a lot of that potential is wasted on those that value it so highly for its scarcity rather than its utility. Why can't we just hoard iron oxide?
Another interesting story about precious metals in bank vaults:
During the Manhattan project they needed to build something with a ridiculous amount of copper coils, and copper was scarce due to the war. So they used silver instead. Who cares if it's more expensive, if that machine is going to be more heavily guarded than any bank anyway and you can always melt it back into ingots when you're done?
Since you bring up the Manhattan Project... Feynman described during the Manhattan Project they were testing different metals to find one with the right neutron properties. At one point they wanted to test gold, so they ordered a 6 inch gold sphere. The powers-that-be pointed out that the sphere would be 80 pounds of gold and would cost a fortune, but they ended up delivering it from Fort Knox. Gold didn't have the required properties, so the scientists ended up using the sphere as a doorstop for a while. The other interesting part of the story is the librarian who received the gold amused herself by asking people to move the small package for her - they failed, not expecting a small package to weigh 80 pounds; gold is much heavier than you'd expect.
> Gold didn't have the required properties, so the scientists ended up using the sphere as a doorstop for a while.
If I remember the story correctly, it was the door stop to a room that held fissible material - gold wasn't expensive compared to the materials they were working with!
When I started working in Investment Banks, I was sent on an Introduction to Finance course. Next to me was an older guy (50's) with a massive bruised thumbnail. I asked him how he did it and told me he worked in the vaults and had dropped a gold bar on it.
Gold is quite close to tungsten in density (19320 kg/m^3 for gold vs 19300 kg/m^3 for tungsten). The criminal mind has found use for that factoid: they coat tungsten bars with gold and pass them off all gold (after all, they come close to passing the Archimedes test). However, the speed of sound in tungsten is significantly different than in gold. This fact allows ultrasonic thickness meters† to be used to verify nondestructively that a gold bar is golden thru-and-thru.
They didn't take it out of the treasury, on a technicality: The room the machine was in was declared a bank vault, and 99.9% of the silver was recoverable, so it never really left!
Col. Nichols from the Manhattan Project went to the director of the Treasury and said that they needed to borrow 6000 tons of silver. Who replied frostily: "We measure silver in troy ounces here."
I think you need to show a connection between storing gold in a bank vault and how somehow, that affects it being used in scientific purposes.
I would have to guess that perhaps at most, 1 gram of gold would be needed for a space visor? The process involved in deposition must be considerably more expensive than the actual material involved (a gram of gold is about $44 at today's prices).
(Actually about 300 square feet can be covered by 1 ounce of gold (31.1 grams per troy ounce) I believe; so the amount would be less than 1 gram, but maybe they would waste some, etc. )
> I think you need to show a connection between storing gold in a bank vault and how somehow, that affects it being used in scientific purposes.
? This is supply and demand: the use as a currency/store-of-value is extra demand, hence the price is higher, and other users (like science) will demand less gold.
> The process involved in deposition must be considerably more expensive than the actual material involved (a gram of gold is about $44 at today's prices).
Which is ~$44 you wouldn't have to pay for another metal, and the penalties only get worse from there. (Want to manufacture a billion smartphones for Africa using efficient gold circuits? Sorry, not going to work out well.)
>Which is ~$44 you wouldn't have to pay for another metal...
You wouldn't have to pay $44 for another metal because they are vastly more abundant[1], the consequence of which is that they are cheaper to produce.
Yes, demand affects the price too, but given gold currently costs over $32/gram to produce[2] (average, individual mines vary considerably), I don't see how the price is going to magically drop if it stops being used as a store of value.
The price drops because it rapidly becomes less scarce as hoarders of it rapidly sell it off for industrial use. See, for a similar case of a market flooded by a scarce good, the depletion of the strategic helium reserve floating away in party balloons the world over.
Gold is expensive because billions of people think it is worth hoarding. You don't have that percepetion with aluminum, so in a lot of circumstances where gold would act as a better substitute, you have to use the less efficient element regardless of physical scarcity because billions of people want to just stick that gold in a box and hoard it rather than use it, and that demand means an elevated price.
Gold isn't scarce because there isn't much on Earth in this sense. Gold is scarce because all the people hoarding it take that gold out of the market and there are billions of people that want gold not for practical utility of the element but to hoard.
But wouldn't the resulting iron shortage just cause bigger problems? I mean, gold is great, but steel is really useful. Not to mention all that oxygen we'd be locking up, too. People might start suffocating!
</sarc>
Better for what? If you want to have stable money supply, commodity money is better. If you want to manipulate money supply in order to achieve political purposes - of course fiat money is better.
BTW, if fiat money are so great and gold money is so inferior, why exactly the government snatched the private gold in the 30s[1]? Did they want the inferior thing so much that they had to force people to give it up because they wouldn't voluntarily exchange it for the much better thing? I imaging they were rescuing those people, that's what it was. A sacrificial act by the Feds.
The gold standard wasn't as "stable" as you think. There were severe inflation crises during the California and Alaska gold rushes, while the Nevada silver rush made bimetallism untenable.
Your other argument is incoherent--there's no fundamental reason to build monetary policy such that it favors individual investors over the health of the economy as a whole. In fact, if people simply hoard money rather than spending and investing it, that's generally an indicator of a poor economic system that can cause the type of deflationary spirals that caused the Great Depression in the first place.
in ground gold reserves are reasonably well known and factored in. There is a finite amount of gold in the crust. There is no limit to the amount of digits one can add to the banks balance sheet.
dollarizing won't be possible for the USD.
We only have estimates for unknown discoveries, and the margin of error is huge for those. Not well known at all. There is definitely a finite amount of gold in the crust, but no one knows how much, and even "knowing" how much China has locked up in their vaults is difficult (they keep it secret for obvious market manipulation reasons). Of course, we are less than a hundred years away from being able to mine asteroids, but I'll doubt we'll bother mining for something as intrinsically worthless as gold.
The US dollar is still a very stable currency, whatever the libertarian alarmists claim.
1. User A submits link to HN explaining the intrinsic properties of gold that are useful for space program at NASA.
2. User B lists a number of additional areas in science and technology that rely on the intrinsic properties of gold and bemoans financial system reliance on gold. Somewhat off topic and interesting discussion of fiat currencies ensues.
3. User C comments that gold is intrinsically worthless.
Great example of why I find HN so interesting and infuriating.
The value of gold in any of those technologies is only worth as much as the alternatives that accomplish the same effects. Gold as a concurrency is completely detached from gold as a useful commodity.
people have been telling us that probable in-ground oil reserves have been known for decades, but those estimates keep going up. I see no reason to believe there is a better estimate for in-ground gold reserves, nor do I believe the true size of those reserves is factored into the price. Considering the 40+% margins shown by Barrick Gold, I doubt even the marginal cost of mining gold is factored that well into the current price.
Gold currency was only ever a "promise" to pay. Banks could invent money out of thin air just as easily with gold-backed currency as with pure fiat currency, and banks did just that since the founding of the U.S.
There's some investment debate but ethically, there's no debate.
It's simply not "right" to tie the value of everything in society to the value of a specific good. Gold, like all other goods should be free to have a value that is intrinsic to its uses (of which there are many in science and engineering) and other goods should not be subject to price fluctuations due to supply and demand issues related to gold.
Obviously, people have issues with their fiat currency issuer – especially since currencies tend to be a government monopoly and lots of governments abuse that monopoly. However, that's well outside the point I was making. In any case, that's not an issue with fiat currency per se but with government monopolies on fiat currency (something that currencies like Bitcoin have set out to address).
Debate can't really be had. Fiat currencies are better and more predictable... right up until they aren't. Which takes so long that hard-earned experience has long since diffused.
Err, some of those are tied to stock exchange crashes, others to extended warfare periods etc. And all are tied with ever-expanding industrial production, which is another independent parameter.
When did the actual observation that gold economies are not more stable happen?
The list provided only shows that they also have crises -- it doesn't show how those crises measure (respective to fiat currency economies) in magnitude, frequency and consequences.
Well, go on and make your point then. They seemed pretty frequent, consequential, and high-magnitude to me, certainly comparable to the 20th and 21st centuries (and even the Great Depression began under the gold standard).
You can buy gold on the open market and use it as you wish. I think the important uses for gold can use small amounts, like gold plating electrical connections. There's no use for bulk gold that justifies the cost.
Is there not a way to synthesize gold, like how diamonds can be synthesized (obviously a different process.) I searched around, and I guess there isn't a good process for this, yet.
Also, how much could NASA really be spending on gold, anyway? They're already spending billions on the rest of their space program.
Gold, being an element, needs nuclear processes for manufacture instead of chemical processes (like diamond). Before modern particle accelerators, this was flatly impossible, and even today, it is very, very hard and expensive. The cost to produce an amount of gold like this is millions of times more than it's value.
Somewhat interestingly, gold is actually being actively destroyed in particle accelerators, as it has several properties that makes it a desirable target. As my professor once put it, we finally have the secrets the alchemists only dreamed of, and we use them to destroy gold.
I have a rather vague recollection that gold has been transmuted from other elements in experimental (fission, I presume) reactors as well, although the best reference I can find right now is [1]. Accelerators do seem to be the modern/"practical" approach though.
Which properties in particular make it a good target?
Edit: more details from wikipedia[2] suggest starting from either mercury or platinum, although it's all a bit fiddly and isotope-specific. That page has some other interesting facts as well - I'd never really thought of element synthesis as economically practical (and with capital equipment costs, probably still isn't), but tungsten ($30/kg) -> rhenium ($6k/kg) -> osmium ($12k/kg) sounds like a nice business to be in if you can solve the practical problems.
When the balloons all run out, we might want to start making our own helium as well, which has the bonus of being really quite easy to do.
Gold has a large cross section, which basically means it presents a big target (amusingly such measurents are made in units of 'barns'). It's also stable, so you don't have to worry about natural decay events polluting your data.
> Is there not a way to synthesize gold, like how diamonds can be synthesized (obviously a different process.)
To convert other forms of carbon into diamond, you just need to simulate the conditions in which diamonds are formed (heat and pressure inside the earth.)
To convert other elements to gold, you just have to simulate the conditions in which gold is formed, which, as a heavy element, I'm pretty sure is reproducing a nuclear process that occurs in large stars or possibly supernovae, i.e., something you can reproduce only on Earth only on a very small scale using particle accelerators (or maybe nuclear weapons.)
Actually, only a supernova or equivalent energy magnitude event.
Fusion only releases energy up to iron. Creating heavier elements consume energy in the reaction rather than releasing it, therefore cannot sustain a reaction.
Fission goes the opposite way. Heavier elements than iron release energy.
I think the inside of a star is not perfectly clear-cut. Various elements get created and cycle, with only the energetically-favorable ones accumulating. It's not altogether unlike chemistry.
What little I know of this comes from wikipedia, but I think there are other ways to synthesize elements apart from fission and fusion. Sometimes they simply catch a neutron, and the decay of a particle produces a different element.
> Is there not a way to synthesize gold, like how diamonds can be synthesized ...
Diamonds are a form of carbon, all you need is a different form of carbon and sufficient pressure. Gold is an element, and creating it requires a supernova. Were this not so, if gold could be synthesized, it wouldn't be selling for $1300/ounce.
> if gold could be synthesized, it wouldn't be selling for $1300/ounce.
That's not by itself true. If gold could be synthesized for less than $1300/ounce, then it wouldn't be selling for $1300/ounce. As noted in sibling comments, it is possible to synthesize. It's just unreasonable to actually do so in any meaningful quantity.
Let me amend my original claim: "If gold could be synthesized with something other than a multi-billion-dollar accelerator and produce daily yields greater than nanograms ..."
While the other answer made me laugh, the reason is because gold is an element. Diamonds can be manufactured because they are made out carbon, and carbon and cheap and plentiful.
You either have gold or you don't. Alchemy tried to convert elements into other elements which is nearly impossible (The sun and other nuclear reactions do this, but not directly to specific elements).
It's not actually gold foil, it's typically a mettalised polymer film, Kapton. This becomes part of a multi-layer insulation material where each layer is composed of a different material that has certain advantageous properties, with all of the layers separated by a small shim between them to avoid thermal conduction.
I really gotta stop playing so much Kerbal Space Program.
Most of the shiny 'gold' things seen in aerospace and motorsports is just vapor deposited Kapton/polymide.
But there are applications where gold is indeed used - but it's unclear (in the literature I've read) when/where it's appropriate to use gold. The helmet use case I can believe. I also imagine large swathes of gold would be problematic - structural surfaces being unnecessarily conductive or introducing inductive noise.
The US Navy EA-6B Prowler, an airplane that emits a LOT of radio frequency energy, has a conductive gold layer on its canopy for Faraday cage reasons, to protect the crew from the radar jammer.
I dunno how it is in the US, but here in Brazil, firemen also use gold-plated helmets.
I once in a first aid training asked one fireman that was present to borrow me his helmet, because I was doubting you could see through it (I was 12).
The nice man put the helmet correctly on my head, and to my surprise, I really could see! Everything was blue, but I could see everything, it was really cool.
This article explained to me WHY I could see... I was still puzzled (I thought gold reflected 100% of visible light)
It depends on how thin it is. There is no 100%, the thinner the more is transmitted (weighted by the curve shown in the linked article). A solid block of steel would be transparent if you illuminated it with enough light.
I have known for a while (since I read Quicksilver) that gold becomes visibly transparent if you hammer it thin enough, and transmits greenish light, but I have never been able to find a picture of this or a video of someone demonstrating it. How is this possible?
You've seen it before... Stained glass. Stained glass was one of the first use of nanoparticles and plasmonics to become commonplace. The wide range of colors that you can get in stained glass is due to the nano properties of the materials you add to the glass. The effect is due to surface plasmons - electric field waves that travel on the surface of conductors. Much like ocean waves, plasmons are created from light's electric field. They bounce back and forth, and since they are only permitted on the surface of a material, there are limits on what waves can exist. This is what gives them the weird properties - the size and shape determine the optical properties.
On another tangent (this one's pretty cool) - since you can tune the properties of these nanoparticles, you can make them respond in a specific way. Let's say we have a cancer cell that we want to kill, and only that cancer cell should die. We can create nanoparticles that bond with that cancer cell, and only that cancer cell. But how do we kill it? We can tune the absorption spectrum of the nanoparticle to absorb infrared light - light that is transparent to the human body. We create a small heater that absorbs tons of the input energy, while keeping the rest of the area cool. Localized heating destroys the nearby cancer cell.
Gold reflects reddish light. That means only greenish light gets through. You don't need a solid piece of gold to see this; anything tinted with gold dust will work as well.
I am surprised that I can't find evidence of consumer gold foil sunglasses. Are the optical properties really terrible for day-to-day use? I'd think they'd be pretty sharp looking, and the cost of the gold shouldn't be prohibitive.
Most sunglasses are intended to reflect or absorb UV. As you can see in the OP, gold is only good at absorbing IR, which the atmosphere (and clouds and trees) do a decent job of absorbing when we are at ground-level. The gold would be more style than function for non-astronautical activities.
This reminds me of uchuu kyodai or the space brothers anime where hibito wraps his comadre's body with a gold like foil to keep his body warm but also to reflect sunlight when it gets too hot.
This anime is pretty realistic and I recommend you watch it if you'd like to know what it takes to be an astronaut.
Reminds me of the movie Sunshine, with their striking gold space suits. I thought it was just for theatrical effect until I read it was actually based on this theory.
The gold-leaf shielding in Sunshine was influenced by NASA satellite designs for deflecting heat and other forms of radiant energy. Boyle designed the gold-coloured space suits along these lines despite persistent encouragement to model them after the NASA template.
I am not qualified to understand the chemistry, but I got the idea from somewhere that the ionization of the atmosphere filled near earth space a highly corrosive environment because a large number of liberated hydrogen atoms were present. Gold is inert and therefore not subject to the corrosion that would otherwise take place, and also would not catalyse other material.
Maclaren also lined the engine bay of the 90's F1 road going car with gold. Additionally many of my friends who highly modify their turbo charged cars line the interiors with gold foil (although I can't help but think this is mostly for aesthetics :).
Doesn't it look cooler if we use gold? Short of practical purposes, if you have something that you need to convince a politician to support, wouldn't gold be better than silver for no reason other than it looks good?
The Admiral in charge of the group that designs nuclear submarine propulsion plants had a famous quote about switching the naming of American submarines away from fish to things like U.S. cities, states, etc. as being because "fish don't vote on our budget".
Religious objections were raised when they got around to naming a nuclear fast attack submarine after Corpus Christi. That's why SSN-705 was christened† the City of Corpus Christi, rather than just the Corpus Christi.
