Determining rock ages remotely would create new possibilities for planetary science.
A teleoperated robotic rover retrieves a sample from an outcrop on the Moon. Determining the formation age of such rocks is an important scientific goal (artwork by Pat Rawlings)
Returning samples to Earth for analysis is one of planetary sciences’ holiest of grails. Although many different, complex measurements on returned samples are possible, one of the most important ones – from the standpoint of geologic study – is to determine the age of a rock. Ages are determined by obtaining precision measurements of the amounts of different isotopes of certain elements (some of which are radioactive and decay at known rates). By comparing the ratio of these radioactive elements to their daughter products, the amount of time that has elapsed since the rock formed can be calculated and thus, the age of that rock can be inferred. If we know from which regional unit the rock comes, we can infer the ages of major events in planetary history. This is one of the principal reasons why planetary scientists crave samples from other worlds.
We’ve determined the ages of most of the more than 380 kg of rock and soil ...