Scientists uncover hidden history of the Moon in new analysis of soil samples brought back by «Apollo 16» half a century ago

A new study of the lunar soil collected by the astronauts «Apollo 16» in 1972 has allowed scientists to reconstruct billions of years of the Moon’s history.

In 1972, after a «lunar landing» in the multi-cratered Cartesian region of the lunar highlands, astronauts John Young, Charles Duke and Ken Mattingly collected approximately 96 kg of material from the lunar surface. Preliminary chemical analysis of the samples revealed the presence of various noble gases, including argon and xenon — which are essentially important tracers for identifying the impact of solar wind and asteroid impacts on the formation of the lunar surface over billions of years.

Most of the samples had been carefully studied in previous years, but one of the last ones was unpacked by NASA «» two years ago — and much of the knowledge about the evolution of the Moon is derived from it (in particular, regarding the age of our satellite, which turned out to be 40 million years older than we thought). The latest analysis opens «new chapters» of this story:

In analyzing the samples, Nottingham and his colleagues used mass spectrometry techniquesMass spectrometry is a method of determining the chemical, phase composition and molecular structure of a substance based on the recording of the mass spectrum of ions formed by the ionization of atoms and/or molecules of a sample. to catalog the gases and their amounts in the samples, which helped them «determine how long the samples had been exposed on or near the lunar surface».

The chemical composition of the gases that were exposed to these «regolith breccias»A breccia is a coarse fragmentary rock composed of sharply angular cemented fragments larger than 2 mm. by asteroid impacts shows that they have been exposed to solar wind and asteroids for a long time. The specific age of each of the samples varied quite a bit: from 2.5 billion years to less than a billion. This indicates that the lunar soil around the landing zone is «mixed», with some gases coming to the surface as a result of recent impacts.

Nottingham says that the study, in addition to offering a clearer picture of the effects of asteroid impacts on the Moon, will help in planning future missions and identifying potential locations for satellite bases.

The study was published in October in the journal Meteoritics & Planetary Science (via Space.com).