Spike-shaped structures are produced by light-driven ablation in very different contexts. We report the first laboratory generation of centimeter-scale snow and ice penitentes.
Under special conditions bacteria excrete an attractant and aggregate. The high density regions initially collapse into cylindrical structures, which subsequently destabilize and break up into spherical aggregates.
Penitentes and suncups are structures formed as snow melts, typically high in the mountains. When the snow is dirty, dirt cones and other structures can form instead.
