I look out across Trinity College’s Great Court and spot a fabulous silver puffer jacket catching the early morning sun. It belongs to Dr Hilke Schlichting, Professor of Exoplanets and Planetary Sciences at UCLA, Visiting Fellow at Trinity, and Murray Edwards Natural Sciences alumna. Hilke is in Cambridge for just one week, but has agreed to meet with me to discuss her work before her eleven-hour flight back to California later this afternoon.

What does your research entail?

On a day-to-day basis, we are interested in understanding the formation of planets, both in our solar system and in all the planetary systems that we discover around other stars. In practice, we mostly work on theoretical models to explain their formation and evolution – we then compare these models with data taken by various telescopes on the ground and in space.

What is an exoplanet, and why do we care about studying them?

An exoplanet is a planet that orbits a star other than our Sun. I think the main reason we care about studying them is because we’d like to answer the question of where we come from, and whether we are alone in this universe? A long time ago, we thought we were the centre of the universe, and then we understood that we were all orbiting the Sun. For a while, people then believed that the Sun was at the centre. Now, we’re in this interesting time where we’ve realised that we probably have more planets than stars in our universe – it’s making it more and more likely that there are other places where life may be possible.

“Ultimately, we would like to find and characterise habitable planets around other stars to try to determine whether there is life elsewhere”

What are you currently working on?

When we observe some planets, mostly what we can study is the light that gets transmitted through the atmosphere from the host star. By looking at that spectrum, you can infer what elements are there. We’re trying to use this elemental signature to tell us about the rest of the planet: how much does it reveal about what we can’t probe, and what’s hidden underneath?

Did you always know you wanted to go into astronomy?

It was always something that I’ve been fascinated by as a child. I just think for the longest time I never thought it was a realistic career path!

What’s the most exciting result you’ve produced in your research?

The answer to that question changes every couple of years because I get excited about something new! Depending on what we’re working on, I think that’s the most interesting thing.

At the end of my PhD, we looked for really small objects in the outer solar system using stellar occultations, meaning we’re trying to catch them by chance when they transit background stars. These objects are so small that you can’t see them directly in the light they would reflect back to you. We came up with a clever way to look for them, so I’d say that was a fun and surprising thing we were able to do.

You have an asteroid named after you – why, and how does it feel to have that sort of recognition?

It was for my work on the Kuiper Belt, mostly during my PhD. There are actually loads of asteroids out there, so there’s plenty that can be named – for people who work on small bodies in the solar system, I don’t think it’s such a unique distinction, but it’s a fun fact!

“The more you study other planets, the more you understand how special Earth is”

How does education and research in the UK and the US differ?

Education is definitely very different. At the undergraduate level, in Cambridge, you pick one subject and then you study that for three or four years. I took physics classes throughout, but almost nothing else apart from some maths for physicists. It’s very intense in one subject, whereas in the US, you would be majoring in physics, but still have requirements to take some languages or history classes. There’s more breadth, but less depth.

At the PhD level, in the UK, people usually start immediately with a specific research project and work on that for three to four years. In the US, the typical time is five or sometimes even six years. In the first two, people will take classes in the area of specialisation, so it’s a little bit like catching up or getting the depth they didn’t get as an undergraduate. But then you have more time to decide what your main research focus will be for your PhD.

What’s next for astronomy?

It depends on the branch of astronomy, but for exoplanet research, I think the next ten years will be spent by better understanding the spectra from the James Webb Space Telescope, and then using that to inform the next major NASA exoplanet mission, with the Habitable World Observatory. Ultimately, we would like to find and characterise habitable planets around other stars to try to determine whether there is life elsewhere.

As a final question, do you have a favourite planet (or exoplanet)?

That’s a great question – I think Earth is my favourite planet. The more you study other planets, the more you understand how special Earth is, and how many things have to be just right to provide an environment that humans feel happy to live in. That’s why we need to take very good care of protecting it.