Jupiter, the largest planet in our solar system, has always been full of surprises.
One of the biggest mysteries lies at its heart. Instead of having a solid, sharply defined core as scientists once expected, Jupiter’s center appears to gradually blend into the surrounding layers of hydrogen and helium.
This unusual structure is called a “dilute core.”
Ever since NASA’s Juno spacecraft revealed this strange interior, astronomers have been trying to figure out how it formed.
One popular idea was that billions of years ago, Jupiter was struck by a massive object about half the size of its core.
That violent collision, some thought, could have mixed up the planet’s insides enough to explain its blurry core today.
But a new study from Durham University, in collaboration with scientists from NASA, the SETI Institute, and the University of Oslo, suggests that explanation doesn’t hold up.
Using one of the world’s most powerful supercomputers, the team ran high-resolution simulations of giant impacts. These simulations included a new method to better track how different materials mix during a collision.
The results were surprising. No matter how extreme the simulated impact was, the planet didn’t end up with a stable dilute core.
Instead, the heavy rock and ice from the impact quickly sank back down and formed a sharp boundary with the surrounding hydrogen and helium. In other words, a single giant impact wouldn’t leave behind the kind of smooth transition zone we see in Jupiter today.
The researchers now believe Jupiter’s dilute core likely developed gradually as the planet grew. As Jupiter pulled in gas, dust, rock, and ice during its formation, the heavy and light materials may have blended together over time, creating the strange interior we see now.
This idea gains even more strength when looking at Saturn. Recent studies suggest that Saturn also has a dilute core, meaning that this structure might be common among giant planets—not the result of rare and catastrophic events, but of slow and steady planetary growth.
Understanding how Jupiter’s core formed doesn’t just matter for our solar system. Astronomers have found many planets around other stars that are similar in size to Jupiter and Saturn.
If dilute cores are created by gradual growth rather than giant impacts, it could mean that complex interiors are the rule, not the exception, for these massive worlds.
As Dr. Thomas Sandnes, lead author of the study, put it: “It’s fascinating to explore how a giant planet like Jupiter would respond to one of the most violent events a growing planet can experience. But in this case, the impact doesn’t explain what we see today.”
The mystery of Jupiter’s core may not be solved yet, but this research offers a clearer picture of how giant planets might have grown—not through sudden chaos, but through slow and steady evolution.
Source: Durham University.
