Scientists are confident that water ice can be found at the poles of the moon inside craters that the sun never illuminates. But observations show that water ice is also present on most of the lunar surface, even during daytime.
In a new study, NASA specialists have updated their old model, making the surface of the moon more rough and convex. In fact, they used images from the Apollo missions: photographs of boulders, craters that actually exist on the lunar surface.
Many computer models simplify the lunar surface by making it flat. Therefore, there are misconceptions that the surface far from the poles is evenly heated during the lunar day. If this were so, then the water ice could not be on the surface by the rays of the Sun for a long time.
In the new work, the authors found that the rough surface created shadows that allowed water to be trapped and allowed to move as the day heats up and cools down again.
As the sun passes a lunar day, surface ice can accumulate in the shadows of the moon, be exposed to sunlight, and enter the exosphere. Then water molecules freeze again on the surface, accumulating in the form of ice or frost in other places hidden from the Sun.