Moon's history gets a wetter rewrite: Groundbreaking study finds more water than predicted in lunar rocks

Tara Hayden, a PhD candidate at Western University, made this significant discovery while assessing a rock sample for a collector. The sample was not just a lunar meteorite but also a valuable repository of information about water on the Moon. Most of the existing data on this topic comes from analyses of samples collected during the Apollo missions.

Initially, experts thought the samples were "poor in volatile substances", implying that the Moon was a dry sphere millions of years ago. However, it wasn't until 2008 that Alberto Saal and other researchers found considerable amounts of water and other volatile substances in the Apollo mission samples. A press release from Western University states that this revelation instigated a reassessment process that spanned 15 years.

Hayden underscores that most of our knowledge about the Moon's water history comes from "samples from the Apollo program". Yet, these samples are thought to "represent only about five percent of the Moon's entire surface". Hayden adds that until new samples collected during the forthcoming Artemis missions reach Earth, meteorites are the only other lunar surface samples that could offer invaluable information.

The focus of analyses was on apatite, a mineral containing volatile elements. This mineral is found in all lunar rocks except glass beads and anorthosites, which signify the Moon's early crust. The researchers emphasized in their press release that these anorthosites are exceptionally old, dating 4.5 to 4.3 billion years back. They're the only known type of rock that emerged directly from the lunar magma ocean.

Experts propose that finding apatite in such rocks has allowed for the first direct study of this previously undiscovered stage in the Moon's evolution. They also believe their timely discovery will assist in shaping the programs and objectives for astronauts partaking in the Artemis missions.