I read an article a few days ago concerning a change in one of NASA’s upcoming missions. By moving up the launch window on a planned mission to 16 Psyche, an asteroid, by a year, they were able to shave three years off the travel time. Instead of leaving Earth in 2023 and arriving in 2030, the probe will leave in 2022 and arrive in 2026, which is made possible by taking advantage of orbital slingshots that would not have been available with the later launch window.

So, why are there suddenly dozens of articles covering this change, a change, it should be noted, that will not actually take place for another half-decade? Simple. 16 Psyche appears to be largely composed of iron. How much iron? 10,000 quadrillion dollars’ worth.

That’s so much that a lot of media outlets are going bonkers:

Oh, wow. Could this asteroid be just as damaging to humans as it was to the dinosaurs?

Well, many of the articles correctly point out that the GDP for the entire world is about $75.242 trillion. I’m no mathematician, but 10,000 quadrillion sounds like a lot more than 75 trillion, by a few orders of magnitude. Maybe bringing that much of a raw material back home would crash the economy, after all.

But, probably not.

I doubt this claim for a lot of reasons. The first is that I can’t find an attribution for the estimated value of the asteroid. Every article I’ve read attributes the number to Dr. Lindy Elkins-Tanton, the lead scientist in charge of the 16 Psyche mission. However, NASA’s press release about the mission does not mention the number. Neither does an article by The Arizona Republic, which covers Arizona State University, where Elkins-Tanton teaches. Intriguingly, while other quotes from the panic-mongering articles are in quotes, suggesting they’re sourced from an interview or press release, the number 10,000 quadrillion never is. I’ve traced it back as best as I can, trying to figure out from which article it was originally sourced, which lead me on a rather wild chase.

The first mention of the number I can find is an in article by The Sun from January 18th.

Here’s the quote as it appears in the article:

“It is valued at £8,072 quadrillion ($10,000 quadrillion), according to Lindy Elkins-Tanton, the lead scientist on the NASA mission” (quotation marks are mine). No citation for this number is given in the article. It’s worth noting that the press release from NASA announcing that this mission had been approved was from January 4th, and did not mention the value of the asteroid. It’s more than a little suspicious that the number appears out of nowhere. It’s even more suspicious given that it comes from The Sun, a tabloid so famous for unreliability that Wikipedia makes a point of telling its users not to trust it.

I don’t want to flat out accuse them of making it up. I just cannot find any evidence that Elkins-Tanton actually said such a thing. I’d be more than happy to be wrong in suspecting that the claim was fabricated, as it means that dozens of journalists did not do their homework when creating new articles about 16 Psyche. It’s especially disappointing given how odd the number is. 10,000 quadrillion is a very British way of representing a number, and Elkins-Tanton went to the Massachusetts Institute of Technology and teaches at Arizona State University. I’ve tried to find information about where’s she from originally, and nothing I’ve seen suggests she isn’t American by birth. Even if she is British by birth, all her work in recent years would likely have been done in American units, just by the nature of who her professors and colleagues have been over that span. I can’t come up with a reason why she would have suddenly given a number in a uniquely British fashion.

Additionally, 10,000 quadrillion is a stupidly large number. How large? Let me put it into a numerical notation.


That’s a 1 followed by 28 zeroes.

Here’s the GDP of the world, in the same format:


Here are those numbers side-by-side:



Huh. Something seems wrong here. I find it hard to believe that a single asteroid, even a large, valuable one like 16 Psyche is worth 1015 times more than every part of the economy in the entire world combined.

So, can we figure out what 16 Psyche is actually worth?

We can try. I’m drawing stats on the asteroid from Wikipedia, so take them with a grain of salt.

16 Psyche is estimated to be 90% iron, 10% nickel. It has a mass of 2.27×10^19 kg. Iron ore is worth about $70.40 per metric ton, which is about 7 cents per kilogram. Nickel costs more, at about $10,204 per metric ton, or about $10.20 per kilogram.

Here’s the formula: Value of 16 Psyche = (% of 16 Psyche that is Iron)(Mass of 16 Psyche)(Value of Iron per kg) +(% of 16 Psyche that is Nickel)(Mass of 16 Psyche)(Value of Nickel per kg)

Here’s the math: Value of 16 Psyche = (.9)(2.27×10^19)(.07) + (.1)(2.27×10^19)(10.20)

1,420,100,000,000,000,000 + 23,154,000,000,000,000,000


Just 25 quintillion dollars. That’s all.

Here’s all of the numbers we’ve had so far:

10,000,000,000,000,000,000,000,000,000 – the number The Sun gives.

24,574,100,000,000,000,000 – the number I calculated

75,242,000,000,000 – the value of the world economy.


That’s a lot of money.

If my calculations are correct, The Sun’s number is still really wrong. You’d need about 500 million 16 Psyches to be worth that much.

On the other hand, that was way more money than I expected.

But could it crash the world economy?

I’m not an economist by trade, but I do know how supply and demand works.

If you were somehow able to drag the asteroid back the Earth, you’d crash the price of iron, which is already pretty low. In 2015, the world production of iron amounted to 3, 320,000,000,000 kg (3.3 trillion kg). Psyche 16 has about 2.04*10^19 kg of iron ore. You’d be bringing an amount of iron that could meet world demand for the next 6.2 million years or so. Would this collapse the world economy?

Probably not. Here’s what we can know for certain:

  1. The price of iron ore would collapse. The greater the supply of a product, the lower the price falls. Dumping 6.2 million years’ worth of iron on the economy would destroy the price of iron. Iron mines would go out of business. Products that were made from iron, especially steel, would also fall in price. Steel is a common building material, and the resulting drop in steel’s price would likely fuel a construction boom. Even if that resulting boom drove the price of steel drove up, and the world somehow consumed multiple years’ worth of iron and steel in a shorter timeframe, the price of iron would remain almost zero, because you would still have about 6.2 million years’ worth of iron.
  2. If you try to sell it all off at once, you won’t make very much money. If the price of iron is almost zero, due to an overabundance of supply, it won’t matter how much you sell, the end result is you not making very much money.
    1. The world can and will only buy so much iron. While, theoretically, the world has $75 trillion to spend on iron, it would have to liquidate everything it owned to spend that much on iron. Which it wouldn’t do, because it only demands as much as it can afford, and as much as it needs. The world doesn’t need 23 quintillion dollars’ worth of iron, and while the low prices will drive demand up, there are only so many uses of iron that would generate profit—and the world economy would only proceed with those.
  3. The world economy is not dependent on iron. Tanking the price of iron would not significantly hurt the economy as a whole.

At this point, it seems premature to say that the world economy would collapse—especially because the world economy is not dependent on high prices for iron. Sure, a lot of iron mining companies would go out of business. However, the economic impact of those closures would probably be balanced out by the resulting construction boom. Additionally, we can look at other commodities for comparisons. When the price of oil is high, companies make less money because the price of transport goes up, and when the price of oil falls, profits go up across the board. It should be similar for iron. And if the world is only buying iron that it can use, then there’s no reason that the economy should be adversely affected.

Overall, the level of journalism I encountered while trying to get to the bottom of this mystery is disappointing. A lot of journalists seemingly didn’t bother to check their sources, and thus repeated a bad number, and it doesn’t seem like many of them know enough about economics to make a claim of this significance.

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