When a stream of charged particles known as the solar wind careens onto the moon's surface at 450 kilometers per second (or nearly 1 million miles per hour), they enrich the moon's surface in ingredients that could make water, scientists have found.
Using a computer program, scientists simulated the chemistry that unfolds when the solar wind pelts the Moon's surface.
As the Sun streams protons to the Moon, they found, those particles interact with electrons in the lunar surface, making hydrogen (H) atoms.
These atoms then migrate through the surface and latch onto the abundant oxygen (O) atoms bound in the silica (SiO2) and other oxygen-bearing molecules that make up the lunar soil, or regolith.
Together, hydrogen and oxygen make the molecule hydroxyl (OH), a component of water, or H2O.