NASA scientists are turning to the moon to solve one of Earth’s oldest mysteries: where our water comes from. A new study led by the US space agency is using lunar soil collected during the Apollo missions to investigate how many water meteorites may have been delivered to Earth and when this may have happened.
The research is based on the lunar regolith, the dusty surface layer of the moon. This has had an impact for billions of years. Unlike Earth, the moon has no weather or geology to destroy its history.
The research was conducted by NASA postdoctoral researcher Tony Gargano, based in Houston at the Johnson Space Center and the Lunar and Planetary Institute. The research team used samples of lunar soil collected during the Apollo missions. The team used a method based on triple oxygen isotopes. This method acts as a fingerprint for identifying the type of meteorites that hit the moon.
The previous studies used metal-based markers, which were sensitive to changes after multiple collisions. However, the isotopes of oxygen do not change under extreme conditions, and this makes it easier to track the meteorite materials.
The research found that at least 1% of the surface material on the moon came from carbon-rich meteorites, which were known to contain water. However, after adjusting the results to take into account the higher number of impacts on Earth, the amount of water in the meteorites turned out to be too small to take into account the amount of water on Earth.
According to NASA planetary scientist and study co-author Justin Simon, the results do not rule out the possibility that meteorites transport water to Earth. However, the study found that late meteorite impacts were unlikely to be the source of Earth’s water.
