A new Durham University study has found that a giant impact may not be responsible for the formation of Jupiter’s remarkable “dilute” core, challenging a theory about the planet’s history.

Jupiter, the largest planet in our solar system, has a mystery at its heart. Unlike what scientists once expected, its core doesn’t have a sharp boundary but instead gradually blends into the surrounding layers of mostly hydrogen (a structure known as a dilute core).

How this dilute core formed has been a key question among scientists and astronomers ever since NASA’s Juno spacecraft first revealed its existence.