Why is Mars red? A new clue to the history of habitability in Martian dust

Planetary Radio: Space Exploration, Astronomy and Science · Apr 9, 2025 · 54m

For decades, scientists hypothesized that Mars’ reddish color came from hematite, an iron oxide thought to have formed through dry oxidation after Mars lost its water. But new research suggests the story is more complex—and more watery—than we once imagined.

In this episode, planetary scientist Adomas (Adam) Valantinas from Brown University joins host Sarah Al-Ahmed to discuss his team’s discovery that Mars’ iconic red dust is likely dominated not by hematite but by a hydrated mineral called ferrihydrite. This subtle but significant shift in understanding could…