Scientists put a number on the true value of the Psyche asteroid, and the figures are astronomical

An asteroid named ’16 Psyche’ has a keen way of keeping scientists on their toes. For years, it sent mixed signals about what it’s really made of. Some measurements hinted at a lot of valuable metals. Others argued for something more complicated.

Mind-boggling numbers are often tossed around that place astronomical dollar figures on Psyche’s worth, based on estimated values of the metals that formed this fascinating asteroid. The real story, however, is far more interesting, and far more scientific, than the headline.

The Psyche asteroid is roughly 124 miles in diameter and sits in the main belt between Mars and Jupiter, sharing space with more than a million other rocks.

Some early ideas suggested it might be the exposed core of a shattered young world. Newer data paint a richer picture – one that blends metal with rock and links texture to temperature.

Fresh eyes on the Psyche asteroid

After years of debate, researchers turned to the ALMA radio telescope array in Chile with 66 dishes to look at Psyche’s own heat.

They observed thermal radiation at millimeter wavelengths and tracked how the asteroid warmed in sunlight and cooled after nightfall.

Instead of the fuzzy, single‑pixel views common for distant asteroids, they produced a temperature map with about 50 pixels, each covering roughly 18 miles by 18 miles. That jump in detail helped them test competing ideas about the composition of Psyche’s surface.

The day-night temperature shifts were gentle – changes of only a few to low double‑digit kelvins across most of the surface – evidence that Psyche’s top layer resists rapid heating and cooling.

In other words, it shows moderate‑to‑high thermal inertia and a surface that is comparatively compact rather than fluffy.

“Low thermal inertia is typically associated with layers of dust, while high thermal inertia may indicate rocks on the surface,” says Saverio Cambioni, a Caltech researcher. “However, discerning one type of landscape from the other is difficult.”

What the data show

Thermal inertia alone cannot settle the metal question, so the team examined emissivity – the efficiency with which a surface emits heat at a given wavelength – and looked for polarized thermal light.

They measured low emissivity at millimeter wavelengths and found that Psyche’s thermal emission was 60% of what would be expected from a surface with standard thermal inertia.

Models that match those data require a significant metal fraction. The conclusion: metal makes up at least 30% of Psyche’s surface.

A second clue came from polarization. Metals often produce strongly polarized thermal signals, but Psyche’s polarized emission was near zero.

Rethinking thermal light

That is not a contradiction. Small metallic grains scattered through rock can scramble the orientation of thermal light before it escapes, leaving a weak polarization signal even when metal is abundant.

As Katherine de Kleer points out, “We’ve known for many years that objects in this class are not, in fact, solid metal, but what they are and how they formed is still an enigma.”

The new data lock in the mixed nature of Psyche’s surface and help clarify how texture can hide polarization.

“The findings are a step toward resolving the mystery of the origin of this unusual object, which has been thought by some to be a chunk of the core of an ill-fated protoplanet,” the study authors explain.

These results correct an earlier assumption: weak polarized thermal emission does not always mean little metal when metallic grains are mixed into rock.

Mission to the Psyche asteroid

NASA’s Psyche mission launched in October 2023 to put these ideas to the test up close and to sort fact from fiction about this unusual world. The spacecraft will reach the asteroid in 2029 and spend about 21 months studying it.

Engineers built a high‑gain antenna into the spacecraft to send data home and added two solar arrays to power the journey, including long stretches far from the Sun. The flight system uses solar electric propulsion to cruise efficiently through deep space.

Once in orbit, the payload will go to work. A multispectral imager will capture high‑resolution pictures through several filters to map geology and search for compositional variations.

A gamma‑ray and neutron spectrometer will measure the distribution of elements at the surface. A magnetometer will check for remnant magnetization, a telltale of past core‑like processes.

An X‑band radio system will track tiny changes in the spacecraft’s motion to read asteroid Psyche’s gravity field and probe its interior structure.

What scientists hope to learn

The mission’s science questions are straightforward and ambitious. Teams aim to determine whether Psyche is an exposed core or a different kind of metal‑rich body; estimate its age; map its topography in detail; and measure its elemental composition.

Taken together, those results will test how rocky planets grew and separated into crust, mantle, and core.

If Psyche is not a bare core, that answer still matters. A metal‑rich, consolidated surface made of rock and metal grains would record a long history of heating, impacts, and alteration.

That history can reveal conditions in the inner solar system when planets assembled and help connect laboratory experiments on metal‑silicate mixtures with a real object we can study from orbit.

Naming an asteroid “Psyche”

Also known as 16 Psyche, the asteroid was discovered in 1852 and named for the figure from Greek mythology. It stands out as the largest known M‑type asteroid, a class often associated with metal‑rich compositions.

Some researchers propose that Psyche could be very old and formed closer to the Sun before migrating to the main belt. Others keep the exposed‑core idea on the table but expect that any core‑like material would now be mixed with rock.

Valuation of a space rock

Where do people get the astronomical valuations for the Psyche asteroid? Here’s the simple “back-of-the-envelope” approach that is normally used.

Start with Psyche’s size and a reasonable guess about what it’s made of. Its total mass is about 2.4 × 10^16 metric tons.

If we assume that the metal mix looks like typical iron meteorites (about 91% iron, 9% nickel, and around 0.6% cobalt by mass), we can pair each metal with a basic sticker price from today’s market.

To keep it simple, use about $100 per ton for iron (close to iron-ore pricing), about $15,000 per ton for nickel, and about $48,000 per ton for cobalt.

Now we do the math with those round numbers. Two-thirds of Psyche’s mass is about 1.58 × 10^16 tons of metal.

Of that, iron would be about 1.44 × 10^16 tons; at roughly $100 per ton, that’s about $1.5 quintillion. Nickel would be about 1.36 × 10^15 tons; at roughly $15,000 per ton, that lands near $20 quintillion. Cobalt would be about 1.0 × 10^14 tons; at roughly $48,000 per ton, that’s about $4.8 quintillion.

Add those together and you get a headline number around $27 quintillion. Remember, this is a “mass × sticker price” fantasy. Real mining would face huge costs and limits, and dumping that much metal into any market would push prices way down. But…it’s fun to think about.

Why asteroid Psyche matters

We cannot sample Earth’s core directly, yet cores shape everything from magnetic fields to volcanic activity. A metal‑rich asteroid offers a natural laboratory for studying those processes at a smaller scale.

By tying mineral chemistry to gravity, magnetism, and surface texture, scientists can check models of core formation against a real object. The implications reach beyond one asteroid to the history of Mercury, Venus, Earth, and Mars.

This reading of Psyche’s signals sets a careful baseline for interpreting other worlds viewed from millions of miles away.

With an orbiter en route and a full suite of instruments ready, the field has what it needs to turn remote clues into a complete, testable story.

The full study was published in the Planetary Science Journal.

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