A frozen moon should look dirty. Space tries hard to make it so, as micrometeoroids, charged particles and ultraviolet radiation steadily grind and scorch surface grains into a dull, charcoal film. Yet some ice worlds shine with an albedo close to a laboratory mirror, as if someone keeps repainting them between each orbit.
The blunt answer is that these moons behave less like dead rocks and more like slow, pressurized machines. Hidden beneath the crust, tidal heating and radiogenic decay pump energy into buried oceans and slushy mantles, building reservoirs of liquid water and volatile gases that act as a geologic reset button. When that pressure vents through fissures, cryovolcanism and geyser plumes eject fine ice particles, which then fall back as a fresh, high‑albedo coating that buries the older, space‑weathered layer.
The brightness, then, is not a cosmetic quirk but an observable metric of internal power. High reflectivity, sparse impact craters and active plume spectroscopy together imply ongoing resurfacing, where sublimation, condensation and ballistic transport constantly shuffle grains across the crust. Space weathering keeps trying to write a dark history on these moons. Their hidden oceans keep erasing the script mid‑sentence.
