A Mole of Moles
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A Mole of Moles
What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place?
—Sean Rice
Things get a bit gruesome.
First, some definitions. A mole is a unit. It’s not a typical unit,<br>though. It’s really just a number—like “dozen” or “billion.” If you have<br>a mole of something, it means you have 602,214,129,000,000,000,000,000<br>of them (usually written \( 6.022\times10^{23} \)). It’s such a big<br>number because it’s used for counting numbers of molecules, which there<br>are a lot of.
"One mole" is close to the number of atoms in a gram of hydrogen. It’s<br>also, by chance, a decent ballpark guess for the number of grains of<br>sand on Earth.
A mole is also a type of burrowing mammal. There are a handful of types<br>of moles, and some of them are truly<br>horrifying.
So what would a mole of moles—602,214,129,000,000,000,000,000<br>animals—look like?
First, let’s start with wild ballpark approximations. This is an example<br>of what might go through my head before I even pick up a calculator,<br>when I’m just trying to get a sense of the quantities - the kind of<br>calculation where 10, 1, and 0.1 are all close enough that we can<br>consider them equal:
I can pick up a mole (animal) and throw it.[citation needed] Anything I can throw weighs one pound. One pound is one kilogram. The<br>number 602,214,129,000,000,000,000,000 looks about twice as long as a<br>trillion, which means it’s about a trillion trillion. I happen to<br>remember that a trillion trillion kilograms is how much a planet weighs.
… if anyone asks, I did not tell you it was ok to do math like this.
That’s enough to tell us that we’re talking about pile of moles on the<br>scale of planets. It’s a pretty rough estimate, though, since it could<br>be off by a factor of thousands in either direction.
Let’s get some better numbers.
An eastern mole (Scalopus aquaticus) weighs about 75 grams, which<br>means a mole of moles weighs
\[<br>(6.022\times10^{23})\times75\mathrm{g}\approx4.52\times10^{22}\mathrm{kg}\]
That’s a little over half the mass of our moon.
Mammals are largely water. A kilogram of water takes up a liter of<br>volume, so if the moles weigh \( 4.52\times10^{22} \) kilograms,<br>they take up about \( 4.52\times10^{22} \) liters of volume. You<br>might notice that we’re ignoring the pockets of space between the moles.<br>In a moment, you’ll see why.
The cube root of \( 4.52\times10^{22} \) liters is 3,562 kilometers,<br>which means we’re talking about a sphere with a radius of 2,210<br>kilometers, or a cube 2,213 miles on each edge. (That’s a neat<br>coincidence I’ve never noticed before—a cubic mile happens to be almost<br>exactly \( \frac{4}{3}\pi \) cubic kilometers, so a sphere with a<br>radius of X kilometers has the same volume as a cube that’s X miles on<br>each side.)
If these moles were released onto the Earth’s surface, they’d fill it up<br>to 80 kilometers deep—just about to the (former) edge of space:
This smothering ocean of high-pressure meat would wipe out most life on<br>the planet, which could—to reddit’s horror—threaten the integrity of the<br>DNS system. So doing this on Earth is definitely not an option.
Instead, let’s gather the moles in interplanetary space. Gravitational<br>attraction would pull them into a sphere. Meat doesn’t compress very<br>well, so it would only undergo a little bit of gravitational<br>contraction, and we’d end up with a mole planet a bit larger than the<br>moon.
The moles would have a surface gravity about one-sixteenth as strong as<br>Earth’s—similar to that of Pluto. The planet would start off uniformly<br>lukewarm—probably a bit over room temperature—and the gravitational<br>contraction would heat the deep interior by a handful of degrees.
But this is where it gets weird.
The mole planet is now a giant sphere of meat. It has a lot of latent<br>energy (there are enough calories in the mole planet to support the<br>Earth’s current population for 30 billion years). Normally, when organic<br>matter decomposes, it releases much of that energy as heat. But<br>throughout the majority of the planet’s interior, the pressure is over a<br>hundred megapascals, which is enough to kill all bacteria and sterilize<br>the mole remains—leaving no microorganisms to break down the mole<br>tissues.
Closer to the surface, where the pressure is lower, there’s another<br>obstacle to decomposition—the interior of a mole planet is low in<br>oxygen. Without oxygen, the usual decomposition doesn’t happen, and the<br>only bacteria that can break down the moles are those which don’t<br>require oxygen. While inefficient, this anaerobic decomposition can<br>unlock quite a bit of heat. If continued unchecked, it would heat the<br>planet to a boil.
But the decomposition is self-limiting. Few bacteria can survive at<br>temperatures above about 60 °C, so as the temperature goes up, the<br>bacteria die off, and the decomposition slows. Throughout the planet,<br>the mole bodies gradually break down...