Asteroid 16 Psyche has baffled scientists for 200 years. Now, new research from the University of Arizona may be bringing us closer to understanding what this giant space rock is really made of, and what it tells us about how planets were born.
Psyche sits in the main asteroid belt between Mars and Jupiter. It is the largest known metallic asteroid, stretching about 225.3 kilometres across.
Scientists believe it could be the exposed iron core of an ancient planet that was violently torn apart billions of years ago. Nasa’s Psyche spacecraft, launched in 2023, is set to arrive there in 2029.
WHAT DO THE CRATERS ON ASTEROID PSYCHE TELL US?
Researchers at the University of Arizona’s Lunar and Planetary Laboratory ran computer simulations to study how a large crater near Psyche’s North Pole could have formed.
The crater is roughly 48 kilometres wide and 4.8 kilometres deep. By modelling different impact scenarios, the team was able to make predictions about what the asteroid would look like on the inside.
The study, published in JGR Planets, tested two theories. One suggests Psyche has a layered structure, with a metallic core wrapped in a thin rocky shell. The other suggests it is a uniform jumble of metal and rock, the result of a catastrophic collision that mixed everything together.
Their simulations found that an impactor about 4.8 kilometres across, travelling at roughly 4.8 kilometres per second, could have produced that crater. Both interior models were consistent with the result, meaning the spacecraft will have to settle the debate when it arrives.
DOES THE EMPTY SPACE INSIDE AN ASTEROID MATTER?
One surprising finding was how much the asteroid’s porosity, or the amount of empty space inside it, affects how craters form. Porous asteroids absorb impact energy differently, producing deeper and steeper craters. This had been largely ignored in previous models.
Professor Erik Asphaug compared the approach to walking into an abandoned pizza parlour and working out how it operated from the leftover equipment and ingredients. If Psyche is indeed an ancient planetary core, it could offer scientists a rare look at what the deep interior of an early planet looked like.
The Psyche mission is led by Arizona State University, with Nasa’s Jet Propulsion Laboratory managing the overall mission.
