Mercury, the closest planet to the Sun, surely has no frozen water, right? Guess again: Solar winds form ice • The Register
https://www.theregister.co.uk/2020/03/17/water_mercury_ice/
❄ Here’s how they form: charged particles from the solar winds bombard the soil on Mercury’s surface. When a proton (H+) smashes into molecules containing hydroxyl groups (OH), it kicks off a chemical reaction to form water (H2O).

These water molecules rise above the surface. Sometimes they don’t survive and break apart under the sunlight. But in some cases, they float around and land in the shadows of #Mercury’s craters.

These nooks and crannies receive little light and are kept at -200 degrees Celsius. Over time, the water molecules that settle here freeze and turn into ice.