NASA’s InSight mission uncovered Mars’ mantle as chaotic and fractured, resembling a Rocky Road brownie rather than a layered planet. Seismic data revealed ancient fragments, some over 4 km wide, preserved by a rigid crust for more than four billion years. The findings offer fresh insights into Mars’ explosive past and the evolution of rocky planets.NASA’s InSight mission uncovered Mars’ mantle as chaotic and fractured, resembling a Rocky Road brownie rather than a layered planet. Seismic data revealed ancient fragments, some over 4 km wide, preserved by a rigid crust for more than four billion years. The findings offer fresh insights into Mars’ explosive past and the evolution of rocky planets.