What's it like being an astronomer?

An interview with Hubble scientist Dr Catherine Heymans of the University of Edinburgh

In Issue 2 of the Starlight Newsletter, which is now available to download (just click on the image at the top of the website), we interview Dr Catherine Heymans, an astronomer who has worked on the Hubble Space Telescope. Here is the full length interview to get you inspired!

What kind of work do you do with Hubble?
I look at how galaxies are changing with time. Hubble can stare at the same part of space for a very long time and collect light from very distant objects. Because the light that you see in the night sky has taken time to get to us, you are actually looking back in time. We can use this fact to see how galaxies are transforming and evolving as the Universe gets older. We look at how their stars age and their shapes change, and recently we have been looking at how those changes are affected by the dark matter that surrounds them.

What is dark matter?
The majority of the matter in the Universe is dark, which means we can’t see it, but we know that it is there. If you have a ball on a string and you are spinning it around your head, then the string is keeping the ball spinning around. In a similar way gravity keeps the stars spinning around galaxies, but there is not enough visible matter in galaxies to create enough gravity to hold on to the stars, so we know there must be more matter there, we just can’t see it, so we call it dark matter. What Hubble lets us do is look at light from very distant galaxies, and when that light comes towards us it travels through the dark matter in the Universe. The dark matter leaves its signature on the light of those galaxies, because its gravity can also bend light, and this warps the light of the galaxies into funny banana shapes!

What is the coolest thing about working with Hubble?
Definitely the coolest thing is when you first get the data and you look at it and you think, “nobody else has seen this before – I’m the first person who can see this galaxy!”

How do you look through Hubble?
You tell the telescope operators that you want to look at something, and then they point Hubble at the right part of the sky, and inside it there are electronic cameras, just like inside your digital camera or mobile phone (only much more sensitive). It takes the picture and then it is beamed back down to Earth from a satellite, just like mobile phone satellites, and then it is sent to our computers and we can display them just as we would with a digital photograph.

What new science will Hubble be doing after it is repaired?
I am interested in the Wide Field Camera 3, which is going to be looking at the very distant Universe. We’ll be looking back to when the Universe was less than one billion years old (the Universe today is almost 14 billion years old). The light from these galaxies will have travelled 3 x 10^26 metres before it arrives at Hubble. That’s 3 with 26 zeroes after it (300,000,000,000,000,000,000,000,000). We’re hoping it is going to be able to see what we call the ‘end of the dark ages’. After the big bang the Universe was very hot, and it expanded and cooled down, and there comes a point where gas in the Universe is cool enough to condense and form galaxies. We’re hoping this new instrument will be able to see these first galaxies. It is also going to be able to see light from some of the first quasars, which are really bright beacons of light, and they are black holes in the centres of galaxies eating up some of the gas and that produces a lot of light and heat.

What is your day-to-day job like?
Most people will start the day answering e-mails, and astronomers are no different! I have colleagues all around the world, and everyday they put their new scientific results on the Internet, and it is important to read them and see whether you agree with them or not. I spend some of my day with my postgraduate students, who are working towards a PhD and I am training them. I also spend a lot of time writing proposals to Hubble to photograph new and exciting things. At the moment I’m also working on a new and exciting project that NASA is hopefully going to be putting up into space, a telescope bigger and better than Hubble. I also spend a lot of time doing computer programming – astronomers have to write our own programs to analyse the pictures from Hubble. There is a lot of travelling as well. I use ground-based telescopes in Hawaii, in La Palma in the Canary Islands, and also in Chile. We also get to go to lots of conferences across the world to present our scientific results. Probably the best place I have been to is Kyoto in Japan. I love my job! Every day you are doing new and exciting things. I work in teams a lot, when we are using Hubble we are working with 20 or 30 people, and we all have our different jobs and responsibilities. It can be very social.

Have you always been interested in astronomy?
When I was 14 my physics teacher was chosen to be a representative for the UK on a teacher’s trip to NASA. When she came back to our school, we would ask her about NASA, and she’d get very excited because of course she enjoyed it as well. So astronomy was always an exciting part of physics and a way of avoiding the boring parts! I had my own telescope too. So from 14 years old I was dead set on being an astronomer.

What qualifications do you need to be an astronomer?
You need to do GCSEs in science and maths, and then at A-Level I did Physics, Chemistry, Maths and Further Maths. Maths is the big thing, because all of physics is based on maths. When I finished my A-Levels I went to the University of Edinburgh and I did a combined Masters/Bachelors degree in astrophysics for four years, and then I went on to do a PhD at Oxford University for three years.

What advice do you have for any budding astronomers?
When I was an undergraduate at university I was really lucky to spend two summers working with astronomers, one in the UK and one in Australia. That helped me find out what this job was really all about and if I really wanted to do it. There is always stuff going on at science museums and planetariums, weekly talks and exhibitions aimed at the public, so you can go and look and see whether astronomy really does interest you.

Let us know what you thought of this interview, or who else you think we should interview, by emailing us at yoursay@starlight-news.co.uk. We'll even post your suggestions on the 'Have Your Say' part of this website!