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, NASA 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.
"We think of water as this special, magical compound," said William M. Farrell, a plasma physicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who helped develop the simulation. "But here's what's amazing: every rock has the potential to make water, especially after being irradiated by the solar wind."
Understanding how much water -- or its chemical components -- is available on the Moon is critical to NASA's goal of sending humans to establish a permanent presence there, said Orenthal James Tucker, a physicist at Goddard who spearheaded the simulation research.
