First off I’ll let you into a secret, my names Natalie and I’m a lunar geologist. You guessed it, I study moon rocks, and by rocks I mean small samples of grains and ‘dust’, but awesome nevertheless. My job here is to give you some reasons why I study the Moon and what we can learn from pieces as small as mine.
It all kicked off with Sputnik (USSR, 1957) which was the first satellite to be launched into space. Since then space exploration has grown, with the Moon a major focus, why?… mainly because we can see it and point a rocket at it. Although it’s not that simple, it has been done and men have landed on the Moon to bring us some of those cool samples back here to study. Lunar samples (meteorites-produced by impacts hitting the Moon) have also been collected from places like Antarctica and Africa, where they are not like anything seen in those surroundings.
So why is the Moon important to us? Well the Earth and Moon are ‘close friends’ in a huge neighborhood, so we could assume that whatever happened to the Moon throughout its history also happened to the Earth. The Moon has some of the most extremely ancient surfaces (some up to 4.5 billion years old – near the start of the Solar System) seen throughout our Solar System. Here on Earth these ancient surfaces are now well hidden or destroyed by plate tectonics (movements within the Earths crust) to make new rocks. So a record of what the early earth was like, or at least the inner planets, is preserved in rock samples from the Moon. The outer layer of the Moon, known as the crust, holds a record of this inner solar environment and can give us clues to what the early Earth’s crust and atmosphere were like.
In the case of my studies, I am studying lunar meteorites collected from various regions around the world, as mentioned. I have a particular interest in the thin layer (a few meters in depth) of ‘soil’ (the actual name is Regolith) that covers the Moon’s surface. As the Moon has no atmosphere there is no barrier to stop interactions between the space environment and the Moon’s surface. We can study the noble gas isotopes formed by these interactions. This will tell us things like when the meteorites were excavated, how long it travelled in space before it reached Earth and how long it was on Earth before being collected. It is also possible to estimate how deep the rock was buried before the impact and whether the sample experience a simple history (was never/only at the surface of the Moon once) or a complex history.
Now I figured this complex history part deserved a paragraph of it’s own as it is often the case for lunar rocks. There is a process on the Moon known as ‘gardening’, yes that’s right imagine a huge gardening trowel mixing the regolith layer. However, instead of a trowel mixing the surface its meteorites, but not always the huge dinosaur killing types I’m talking meteorites that are smaller than a gram that constantly bombard the Moon. These micrometeorites rework the regolith, bringing material to the surface and also burying them over millions of year.
To summarise, studying lunar rocks not only helps us to understand our friend in the sky but also allows us to further understand what the early Earth was like and some of the process that occurred throughout the start of the solar system. Also as a kid I always wanted to be an astronaut, so for the time being I’ll settle for the rocks coming to me rather than me going to them, but just for now 🙂