Five-story-high spikes of ice could make it difficult to land on Jupiter moon

Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called penitentes, for their resemblance to devout white-clad monks. First described by Charles Darwin, penitentes are sculpted by the sun in frozen regions that experience no melt; instead, the fixed patterns of light cause the ice to directly vaporize, amplifying minute surface variations that result in small hills and shadowed hollows. These dark hollows absorb more sunlight than the bright peaks around them, vaporizing down further in a feedback loop.

From the research paper in the scientific journal Nature:

We estimate that penitentes on Europa could reach 15m in depth with a spacing of 7.5m near the equator, on average, if they were to have developed across the interval permitted by Europas mean surface age. Although available images of Europa have insufficient resolution to detect surface roughness at the multi-metre scale, radar and thermal data are consistent with our interpretation. We suggest that penitentes could pose a hazard to a future lander on Europa.

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