We know from the Apollo missions and unmanned probes that the Moon's surface is covered with loose, unconsolidated material with a texture similar to soil on earth. How did this material form on the Moon?
◦ The material is mostly volcanic ash ejected from volcanos that are no longer active.
◦ The loose material is mostly micrometeorite fragments and ejecta from impact craters, so is very different from soil on Earth.
◦ The material is produced by spalling from rock surfaces caused by the extreme heat-cold cycles as the moon rotates through a 1 lunar day, or approximately one Earth month.
◦ The same as Earth, but soils are ancient from a time when the moon still had an atmosphere and water.