Between a Rock and a Hard Place

Yesterday, The Japan Times reported that a Hokkaido University team led by Noriyuki Kawasaki worked out when the body from which the Ryugu asteroid formed was born: within about two million years of the birth of our Solar System, more than 4.565 billion years ago.¹ They reached that figure by analysing carbonate minerals – in particular dolomite – from samples that Japan’s Hayabusa2 mission brought back from Ryugu in 2020.²

»We tend to think of destruction as something that knowledge must survive – the damage you do around the edges while trying to find something out. But sometimes it works the other way round. You have to destroy something entirely to be able to ask the question at all«

That asteroid was destroyed three times, in three different ways. First, radioactive decay heated the ice inside the body until it melted, and the resulting water drove the reactions that formed its dolomite. Later a collision shattered the body; gravity reassembled the debris into the rubble pile we now call Ryugu. Billions of years after that, human scientists fed a piece of it into a mass spectrometer, dissolving the dolomite until nothing was left of the crystal – a third destruction, to learn when the first one happened.

There’s a real question hiding in that sequence: not whether destruction can produce knowledge, but what kind of knowledge. Is what it turns up something that’s already true, but inaccessible until you break in? Or does the breaking sometimes manufacture the fact rather than uncover it? The difference matters for what actually happened here.

Take the mildest version: cooking, something you do most days without calling it an epistemic act. Anthropologist Claude Lévi-Strauss discussed the difference between raw and cooked food. Adding fire returns something that’s chemically different from the natural beginning.³ Cooking doesn’t disclose a fact that was already true; it makes the carrot digestible and meaningful, properties it lacked in its raw state. You don’t preserve your way to a meal. Cooking, and eating, are fundamentally destructive acts.

The second kind of destruction knowledge is closer to forensic evidence. A metallurgist trying to explain why a component failed will perhaps cut and polish a section, then study it under a microscope for fatigue lines invisible to the eye. The fact was genuinely there before anyone looked for it: a crack already propagating through the metal. Destruction manufactures nothing here, it just removes whatever stood between you and a fact that already existed, fully formed.

Ryugu’s dolomite is not quite the same. Scientists didn’t find a date stamped inside the rock, no number that a careful eye could read off directly. What they measured was the ratio of isotopes, atoms of the same element with different masses, and what they know independently is the rate at which one isotope decays into another. The date is inferred from a physical law about the world and a chemical history particular to this rock. It isn’t a message that the rock carried; it’s an inference its present state makes possible, but only after several transformations.

There’s also a stranger possibility: sometimes there isn’t an answer there to uncover at all. A quantum particle can exist in »superposition«, several possible states held together until a measurement produces one definite result. Physicist Erwin Schrödinger’s famous cat experiment was devised to make the strangeness of this seem absurd: seal a cat in a box with a device that will kill it if a randomly timed quantum event occurs, and ask whether it’s alive, dead, or in some strange way both dead and alive before anyone opens the box and takes a look.⁴ The paradox has survived as a genuine problem in physics. Measuring, at this scale, isn’t necessarily like opening a box to see what was already inside – the measurement can partly determine what you find.

Ryugu’s case sits closer to that of the metallurgist than the cat: its birth had a true date whether or not anyone measured it. Destroying it didn’t reveal a hidden message or a manufactured fact, but an inference. But that knowledge was purchased at the cost of the specimen that made it possible.

Which makes the 5.4 grams of Ryugu now being consumed in labs strangely precious. Only around 15 percent of what Hayabusa2 brought home has reached outside researchers, in milligram amounts.⁵ The rest stays sealed, a bet that a better instrument, later on, might provide knowledge worth more than a simpler answer today.

We tend to think of destruction as something that knowledge must survive – the damage you do around the edges while trying to find something out. But sometimes it works the other way round. You have to destroy something entirely to be able to ask the question at all.

The body that became Ryugu is long gone. Pieces of it survived. Destroying those pieces now lets us know when it was born.

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