Scientists have long been intrigued by an enormous potato-shaped asteroid, dubbed 16 Psyche, that they suspect to be teeming with metal — and therefore potentially worth a ludicrous amount of money to future asteroid mining operations.
The 173-mile object, which orbits the Sun in the asteroid belt between Mars and Jupiter, features two enormous crater-like depressions, which researchers say could be closely related to its still largely unknown origin story.
In a new paper published in the journal JGR Planets, an international team of researchers tried to get to the bottom of one of the key questions regarding 16 Psyche that remains unanswered. Is it a core of a planetesimal, a billions-of-years-old building block of a planet, in which case it would have a “large metallic core buried under rocks,” or is it a “homogeneous mixture of iron and rock?”
Put differently, could 16 Psyche be the ancient exposed remains of a planetary core whose crust and mantle were blown off, or is it a separate primordial lump of far less dense and potentially riddled-with-holes rock that either started out metal-rich or became blended with metal after colliding with other asteroids?
While the latest paper doesn’t necessarily exclude any of these possibilities — its simulations support both hypotheses — the goal was to know what to look out for once NASA’s mission to the space rock, which launched in October 2023, arrives roughly three and a half years from now.
Once there, the spacecraft could finally allow us to solve the mystery surrounding 16 Psyche’s history once and for all. As Universe Today points out, 16 Psyche’s size makes it far more approachable than the thousands of miles we’d have to drill into the Earth. (So far, we’ve only made it around 0.2 percent of the way to our own planet’s center.)
For their paper, the researchers took into consideration 16 Psyche’s unusual dented shape, previous findings that concluded it may be teeming with metal material, and its porosity.
“Large impact basins or craters excavate deep into the asteroid, which gives clues about what its interior is made of,” said first author and University of Arizona doctoral candidate Namya Baijal in a statement. “By simulating the formation of one of its largest craters, we were able to make testable predictions for Psyche’s overall composition when the spacecraft arrives.”
“One of our main findings was that the porosity — the amount of empty space inside the asteroid — plays a significant role in how these craters form,” she added. “Porosity is often ignored because it’s difficult to include in models, but our simulations show it can strongly affect the impact process and shape of craters left behind.”
A more porous asteroid would theoretically feature deeper and steeper-sided craters on its surface. The researchers are hoping that close-up observations by NASA’s Psyche mission could allow them to determine its porosity and therefore infer if its interior is metal clad in rock, or a more homogenous mix of both.
To explain their line of thinking, the researchers used the unusual metaphor of an abandoned pizza parlor.
“The cooks have long left, but you can look at what’s left behind — the ovens, scraps of dough, the toppings — and make inferences about how the pizzas were made,” said coauthor and University of Arizona’s Lunar and Planetary Laboratory professor Erik Asphaug in a statement. “We can’t get to the cores of Earth or Mars or Venus, but maybe we can get to the core of an early asteroid.”
The team came up with two possible interior structures.
“One is a layered structure with a metallic core and a thin, rocky mantle, which likely formed if a violent collision stripped away the outer layers,” Baijal explained. “The other is a uniform mixture of metal and silicate, created by a more catastrophic impact that mixed everything together, like some metal-rich meteorites found on Earth.”
By simulating a series of asteroid belt collisions with objects of varying sizes, they tried to reproduce the known dimensions of 16 Psyche’s craters.
“We found that an impactor about three miles across would create a crater of the right dimensions,” Baijal said. “The crater’s formation is consistent with both scenarios of Psyche’s makeup.”
In short, while we’re only inching closer to answering the question of whether 16 Psyche is the ancient remains of a planetary core, we’ll be ready when NASA’s mission gets there.
“When the spacecraft arrives at Psyche in a few years, the geochemists, geologists and modelers on the team will all be looking at the same object and trying to interpret what we see,” said Asphaug.
“This work gives us a head start,” he added.
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