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When I was young, I spent a lot of time exploring nature in the woods and fields around my home. I also enjoyed sports like golf and baseball, as well as reading. At school I always liked maths and science.

I went to University in Toronto to study physics but ended up taking a couple of optional classes in geology to round out my timetable. I really enjoyed learning about the Earth and how physics could be applied at the scale of atoms to the scale of planets, and to figure out how the Earth has changed over billions of years. So, that is what I decided to study, and what I have done ever since.

I still enjoy getting out into nature, playing golf, and learning about our planet.

Deep below the rocky surface of the Earth lies its iron core, most of which is liquid due to the very high temperatures. This Mars-sized sphere of liquid metal has currents and waves, just like our oceans. The motion of that liquid metal is part of how our planet generates its magnetic field.

The magnetic field of the Earth is at least 3 billion years old. Sometimes it has been stronger than today, sometimes weaker, and sometimes it has flipped over – so that compasses would have pointed south instead of north. I use a combination of maths, physics, computer modelling, and observations to try to understand exactly how the field is created, why it has changed through time, and how it might change in the future.

The same is true for other planets. Mercury still has a magnetic field. Mars once had a field but now it does not. We want to learn why some planets kept their field and others lost it. That will tell us things about what is going on deep inside those planets and why they have had different planetary histories.

Scientists think that the magnetic field of the Earth has helped to protect our atmosphere. Electrically charged particles from the Sun can strip oxygen and water away from the Earth’s atmosphere. The magnetic field can deflect those particles around the Earth. This is a slow process, but one that matters over geological time scales – the magnetic field may have helped protect life over billions of years.

When there are big solar storms, those charged particles from the Sun give us the northern lights, but they can also mess with modern technology.  Satellites can be damaged. Radio signals can be disrupted. GPS becomes less accurate. Power grids can fail. If we can figure out how the magnetic field will change over the years and decades to come, we can know if the risk of these “space weather” events is growing.