How It Works
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Interview: Dr Lucie Green

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Dr Lucie Green is one of the world’s foremost authorities on solar physics. We caught up with her to chat about the impact the Sun has on all our lives, the Curiosity rover, and how the ESA’s ExoMars mission plans to follow in NASA’s footsteps, as well as her commitment to engaging with the public through science.

How It Works: How did you get involved in space science initially?
Lucie Green: I guess it was more from an indirect path. I always liked physics from an early age while I was at school. That was my passion: problem solving or asking questions and then finding out ways of answering those questions. But I never had a burning ambition of being a space scientist, and I wasn’t even into amateur astronomy [at that time].
Once I left school I went to do an art course, but then I decided that it was physics I wanted to study at university and it was my parents who mentioned that I could do astrophysics. That was the start of the process that has led me to where I am today.

HIW: One of your main areas of expertise is solar science. What is it about this field that interests you in particular?
LG: It’s for two reasons. The Sun is our closest star and the only one we can see the surface and atmosphere of clearly. So in terms of understanding the physics of a star – how a star operates – the Sun is our best [bet]. Through history there are lots of developments in solar physics that then get taken to the stars to help us understand them – like models of their internal structure or even techniques such as spectroscopy. It is the best way to understand how a fairly typical star works.
The other aspect is that it is important because it’s so close to us and the energy it emits flows towards Earth and we see the effects of that every day. So its direct relevance to us in our day-to-day lives is also key.

HIW: Could you give our readers a new fact about the Sun that they might not know?
LG: The Sun’s hot atmosphere can’t be contained by the star’s gravity, so it manages to escape into space. The gases are expanding outwards at huge speeds of around 400-800 kilometres (250-500 miles) per second and it has taken us a long time to understand exactly how those gases get away and accelerate up to those speeds. In some areas the gases should be held on the star by magnetic structures; the Sun’s atmosphere is filled with magnetic fields. Because the gases in the atmosphere are ionised they should be trapped and tied to these magnetic fields, yet we often see gas winds escaping and it has been a real puzzle [as to] why that happens. However, recently some work done by a colleague of mine has shown there are chimney structures in the magnetic fields that form where the gases can flow out. That’s answered a 50-year-old question in solar physics.

HIW: What are the benefits of taking part in academic and non-academic scientific pursuits in your opinion?
LG: There are lots and lots of benefits. From an inspiration point of view, learning about space science is a great way into science in general. Science gives you so many skills like problem solving, numeracy, literacy – you have to write up your experiments! – and these are skills that you can take into any job. I know people talk about this a lot, but it really is true that you have to have very convincing arguments and very clear logic to be able to convince someone of your ideas. So communication skills come in too. [All of these things are transferable and beneficial qualities in any line of work.]

HIW: You’re involved in the future Solar Orbiter programme that’s currently underway at the European Space Agency. Could you talk a bit about your role?
LG: This is a hugely exciting and ambitious mission and I have been working on it for more than seven years. Solar Orbiter is set to be launched in 2017 and it goes back to what I mentioned earlier about the importance of studying the Sun. There is something called the Sun-Earth connection that has this solar wind that expands out into space and takes energy into the Solar System, as well as generating eruptive events called coronal mass ejections [CMEs] and solar flares that all give off energy that, ultimately – when they reach our world – can create problems for us.
So the Sun has this outflow of magnetic fields and charged particles and we can look at the Sun remotely and see what’s happening, and [detect] the material when it gets to Earth, however there is a 150-million-kilometre [93.2-million-mile] gap in between where we can’t do anything. So the Solar Orbiter will get very close to the Sun – inside the orbit of Mercury – and measure the material coming off it, before it has altered. This will provide us with the missing link: we’ll see what’s happening at the Sun, record what’s happening on Earth and also measure what’s happening in between. This will help us to understand how the flows evolve over time.
My role on the programme has been to decide what science we can do with the Solar Orbiter. You always have to justify the mission by [setting out] the big questions you want to explore or answer. My interest, personally, is in the Sun’s coronal mass ejections. I’ve been studying how they happen and why in some cases they come and hit our planet, however we want to be able to predict which CMEs will strike the Earth and which ones won’t. [The Solar Orbiter should go a long way in helping us achieve just that.]

HIW: What other projects are you working on at the moment?
LG: So many! There are some nice school projects that I’m involved with such as Science Live and Maths Inspiration. I’m very keen to show how we use mathematics in science. I couldn’t do [any of] my science if I didn’t have my maths training. So these projects are events where we gather up to 1,000 students in a hall and do exciting maths and science talks.
There’s always a huge buzz and it’s a great opportunity to meet a large number of students and find out what they are interested in – they are always tweeting so you find out what they really think immediately. My colleagues are currently working on the upcoming ESA mission to the Red Planet called ExoMars.

HIW: Tell us more …
LG: The mission involves building a rover – similar to the Curiosity rover that recently landed on Mars. The major difference, however, is that Curiosity can’t drill into the surface of the planet; it uses a technique where it fires a laser to evaporate pieces of rock on the surface and then analyses the [resulting] dust.
With ExoMars, the plan is to be able to drill into the [top layer] and that will be really important as the surface of the Red Planet is sterilised by high-energy ultraviolet light coming from the Sun. It is probably very unlikely that any life exists on the surface, but it could well be buried beneath.

Dr Lucie Green is a space scientist at the Mullard Space Science Laboratory at UCL. For more information about Dr Green and her work, visit: www.ucl.ac.uk/mssl. You can also follow her via Twitter @Dr_Lucie.