"We could actually see in full 3D renderings how the sulfide melts were moving through the experimental sample, percolating in cracks between other minerals," said Crossley. This groundbreaking observation, part of a study published in Nature Communications, marks a paradigm shift in our understanding of how planets form.
The research, conducted by scientists at NASA's Johnson Space Center, provides the first direct evidence that molten sulfide, rather than metal, can migrate through solid rock and contribute to the formation of a planet's core. This discovery challenges the long-held belief that core formation requires large-scale melting of a planetary body.
The team’s experiments revealed that in the outer reaches of the solar system, where sulfur and oxygen are abundant, these elements act like road salt, lowering the melting point of metals. This allows molten sulfide to percolate through solid rock, eventually forming a core. This process could have occurred much earlier in a planet's history than previously thought.
Using advanced techniques like X-ray computed tomography, researchers created detailed 3D renderings of the process. They also analyzed trace elements in meteorites, finding evidence of sulfide percolation. This new understanding is particularly relevant for Mars, which shows signs of early core formation. The findings suggest that Mars' core may have formed more efficiently due to its sulfur-rich composition.
This discovery has implications for how scientists interpret data from spacecraft and analyze samples from missions to the moon, Mars, and beyond. It also raises new questions about dating core formation events using radiogenic isotopes. This research opens new possibilities for understanding the evolution of rocky bodies in our solar system and beyond.