By Michael A
I make rocks. They do sometimes look like galaxies, molecular clouds and stars (see above), but they are most definitely rocks.
Someone thought it’s a good idea to pay me a generous scholarship just so I can make rocks, as if there are not enough rocks around already.
The problem with rocks is that they are extremely useful. We build stuff from them, on them, inside them, we mine metal and other resources from them, we sculpt them, we bounce them across lakes and other fun stuff. To do (some of) that more efficiently, we need to know how they formed. One of the ways to do it is to synthesise them in a lab, which is what I do.
As a teenager, I always wondered what stuff is made of. So yea, in chemistry classes you learn that water is made from two hydrogen atoms and one oxygen atom, and that we are all made of organic stuff which is mostly carbon. We did put some calcium metal into water to see it merrily fizzing around, but that’s about it, or at least what I can recall. But what about the rest of the periodic table?
What about the funny sounding things like erbium or osmium or the sci-fi sounding things like beryllium or iridium? What are they, and where do you find them? How do they look like? Can I hold a chunk of polonium in my hand? (No, it’s hazardous.)
Mind you, as a high-schooler, you can appreciate that these thoughts were relegated to the back of my mind. I had far more important things on my mind like “will anyone notice if I skip this class?” (yes) or “will she say yes if I ask her out?” (no). Fast forward several years and I’m facing a hard decision: what should I study at university? Eventually I drifted towards geology because it was easy to get into, geology is not a real science*, and they promised a bunch of field trips.
My undergraduate studies brought back my favourite past times from high-school age: asking girls out (one of them eventually married me), and pondering about what stuff is made of.
*Geology turned out not be a real science after all. Real scientists pipette stuff all day in white lab coats, right? We hammer rocks and climb mountains! That was actually fun.
As time progressed I was drawn more and more to the world of petrology. Take just a few building blocks: silicon, magnesium, calcium, iron, aluminium, titanium and combine them in different variations under different temperatures and pressures and you can have so much variety in things (i.e. rocks). This just seemed so much more interesting than the high-school chemistry that we had to do. I started a Masters project dealing with some of the rare earth elements (including that funny erbium from earlier), while tutoring my own undergrads, trying to mould their minds to love petrology as much as I did.
Doing my own research on rocks I collected myself was indeed fun and I truly experienced The Pleasure of Finding Things Out (Feynman 1999), but there was something missing. Large parts of my thesis (and the following paper) can be summarised as this: “I see this, he did an experiment and showed this and she did another experiment and showed that, therefore this and not that”. This was not fundamental enough. I wanted to go to the heart of things. I wanted to be the “he did an experiment” guy. Somehow I ended up starting my PhD at the Research School of Earth Sciences of the Australian National University, a place famous for its infamous experimental petrology lab. My supervisor was (and still is, actually) John Mavrogenes and at first we didn’t think of any defined project I should do. Basically, my task as a young PhD student was to “put some random stuff in a capsule and see what happens”.
Now, this “put some random stuff” part of my PhD is extremely fun. I said that geology isn’t a real science because we hammer stuff. Being an experimental petrologist is downright being a mechanic, and blatantly calling it science. Remember those obscure elements from the periodic table? We have shelves full of this stuff. Just take some, mix it, and abuse it. And we definitely have the ways to abuse it. I will refer to this video from my colleague Eleanor, with me polishing some stuff in the background:
We melt rocks! We make magma! Lava! And the best thing is that we do it in a safe controlled environment, so no need to get killed in an unexpectedly erupting volcano (even though we do have a new student now doing experiments with thallium, known from Australia’s “Thallium Craze” back in the day.) Our job is to take those basic starting materials, the building blocks of Earth, and make stuff out of them that no one ever did before. And almost by definition, putting “random stuff” in there leads to occasionally serendipitous results.
All this is accomplished by operating a variety of equipment, including big hammers, pumps, presses, saws, crushers, grinders, lathes (I didn’t even know what a lathe is), drills, welders (!!), etc. Then we got machines that can put our synthetic rocks in extreme pressures. Think putting a small rock on your head. That’s manageable. Now let’s put a big rock on your head. Getting heavy, no? What about a cubic metre of rock (that would be around 3,000 kg)? That’s a lot of pressure. Now think 30 kilometres of rock on your head. This is the kind of pressure I use in my experiments—and that’s minor compared to some of my fellow students who go down to hundreds of kilometres. Of course, with depth comes temperature and having stuff running at 1200 °C is not unusual (or more!). The machines we use to achieve these delightful feats are called piston cylinder apparatuses. Here’s a picture of some:
This stuff is so good that even this band wrote a song about the piston cylinders a while back!
What’s neat about it, is that we don’t do it purely for fun (or do we?). There is actually science behind this thing. At the end of the day, we’re trying to understand a natural phenomenon. There are few things that feel better than having an idea that might contribute to an answer to one long standing question, and conjuring up some experiment that precisely shows that.
And this is why I love experimental petrology.
ps: I’m not stuck in the lab all day. I also do field work! Look: