Ask an expert: Solar scientist

Dr Lucie Green studies the biggest eruptions in the solar system that occur in the sun’s atmosphere. She was a resident expert on the site for a month, and school pupils had the chance to ask her some questions about her life and work.

What is NASA like?

NASA is a great place to work or visit because there are so many amazing projects being run there. You meet inspirational scientists and engineers who have drive and passion for exploring space, and you can learn about how we are answering the big questions such as 'is there life beyond Earth?' One thing that I remember is that in the entrance to the buildings they have TV screens showing NASA TV. I used to love to stand and watch the view of the Earth from the International Space Station, or see what the astronauts were doing.

Many of my friends go to work for NASA for a couple of years and then return to the UK. However, we have a great space research programme in the UK so I prefer to stay here!

What do you think is the most amazing aspect of our sun?

That’s a tough question for me to answer as there are so many things! Using telescopes on the Earth and in space we get better and better views of the sun as technology develops and we keep discovering new things.

I think one of the aspects that I find most amazing is that the sun produces eruptions of billions of tonnes of material that are able to escape its immense gravitational pull. The sun exerts a gravitational pull 27 times that of the Earth yet these ejections are seen to occur all the time and travel with speeds of millions of miles an hour.

Why do you find the sun more interesting than other aspects of space?

It was pure chance that led me to being interested in the sun. Like many people I had completely overlooked it in terms of astronomy. I thought it was just a bright, but boring, object. And where was the challenge in studying a star so close to us?! However, when I started to look at the sun using telescopes on the ground and in space, I realised that it was an incredibly dynamic and interesting object.

I now think that the sun's proximity and the amount of detail that we can see makes studying the sun a huge challenge. This is the only star in the universe where we can study in detail things like how the atmosphere evolves to produce eruptions and explosions. To really see a star in action, you have to look at the sun. And by studying the sun we are building up a highly detailed picture of how a star works.

Would you ever like to travel in space?

I think I would like to travel into space. Human nature and our urge for exploration is strong and I would love to see the Earth from a different point of view. However, I'm not really an adrenaline junkie so I would have to get over my anxiety first!

I do find the current work by companies like Virgin Galatic to make space tourism available really exciting. The drive to get space tourism going is also leading to new developments in technology as well as raising our aspirations of what can be achieved.

Have you ever been to CERN?

I haven’t been to CERN yet, but I certainly wouldn’t miss the opportunity to visit this fantastic facility. It will help us answer some fundamental questions about the Universe and why matter exists in the first place. CERN is amazing as a physics laboratory but it is also amazing because it is an international endeavour on a massive scale. Thousands of scientists are involved regardless of politics and cultural differences. You are sure to meet some very interesting people there.

Have you experienced a conflict with your ambitions for examples, starting a family and being a successful scientist?

Being a research scientist certainly is a demanding job which can impact on your private life if you are not careful. For a lot of people it isn’t really a nine-to-five job, and you can find yourself moving university departments, for example, as research assistants only have contracts for a few years. This can be disruptive for some people. However, I feel extremely lucky to have the job that I do – in fact it doesn’t even feel like a job! What I do is a passion to me and so far I haven’t had any conflicts between work and my private life.

Do you think normal changes in the sun could be what's causing global warming, rather than it all being down to us?

The sun is a naturally active object and the amount of heat and light it emits varies over time. It is true that these normal changes in the sun have an effect on the Earth's climate. For example, a 'mini ice-age' which occurred during the late 1600s is thought to have been caused by a drop in solar activity which produced a reduction in the heat and light the Earth received.

However, having said that, it hasn't been possible to explain the global warming that we have been experiencing for the last 20 years by what the sun is doing. Actually, the sun seems to have been fairly inactive over the last 30 years. This means if the Earth's climate was only set by solar activity we should see a falling temperature now.

Scientists think that there are many natural factors that are influencing global warming, but even taking all these into account you cannot explain the high temperature that we are now recording. This is what brings us to look at humans. The global warming is consistent with what we expect when the levels of carbon dioxide, and other greenhouse gases in the atmosphere, increase in the way that they have. The dramatic increase of carbon dioxide in the atmosphere is well explained by human activity.

How does matter actually travel in space if there is nothing for it to travel in?

We think of space as being a vacuum but in fact there are a small number of particles out there. In the space near the Earth there are about five particles per cm cubed. However, this is actually a very good vacuum when we compare it to what we can achieve on the Earth artificially! Rather than thinking about matter, we tend to think about whether waves can travel through a vacuum. Light can as no material is needed to carry the light wave. A wave that does need a material to travel through is a sound wave. Sound is produced by a change in pressure – so matter is needed. Space can be considered a vacuum so there are no sounds in space.

Has the sun always been the same or has it changed over time?

The sun has changed over time. Indeed all stars change through their lifetime as they evolve through different phases. When the sun first formed it went through a proto-star stage when the material that formed the sun was coming together and its collapse released energy which made it shine. Later, when the centre of the sun reached a high enough temperature, nuclear reactions began and the sun as we know it was born. The young sun was quite active and its brightness varied. It also blew very strong winds into the solar system, stronger than the wind it produces today. The sun is thought to be half way through its life, and in five thousand million years it will change into a red giant, signalling the start of the final stages of its life.

Your shout!

What do you think is the most interesting thing about the solar system? Share your thoughts by posting a comment using the link below.