Prof. Gerry GilmoreCredit: Gerry Gilmore
Prof. Gerry Gilmore


Gerry Gilmore

Professor of Experimental Philosophy at the Institute of Astronomy, Unviersity of Cambridge

Where do you work and what is your job?

I teach, research, initiate and manage research, and initiate and manage research projects. I also am coordinator of OPTICON, the EC coordination network in optical-infrared astronomy. And, directly under UK Space Agency auspices, I am UK PI for the Gaia data processing and analysis activities. This activity supports about 30 people in the UK at present.

What does your job involve?

I struggle to understand reality – what the universe is really made of, as well as the rather insignificant bits which we can 'see' in light, x-rays, infrared, radio, and so on.

One of the best ways to do this involves weighing things, since all matter has weight. So I weigh galaxies, and parts of galaxies, to measure (via Newton) how much stuff is out there, where it is, and – ambition check!! – what it is. Weighing involves measuring speeds and positions – which is what I do. I’m a Galactic speak-your-weight machine.  Much of this involves the largest ground-based telescopes, of which I am a voracious user. Some can be done only from space.

As well as weighing what there is, we wish to understand how things got to be the way they are – so my other main interest is discovering the formation history of the Milky Way. Galactic archaeology.

Gaia will revolutionise both these major subjects, as well as oodles of other fascinating science, from asteroids to cosmology.

What interested you in working in the space sector?

Science follows experiment – otherwise it is speculation. Precision experiments of the scale needed to measure the positions and speeds of enough stars so we can start to understand an entire Milky Way are simply not possible from the ground – all that horrible air gets in the way. So I work in the space sector since that is the best way to do the best science. As it happens, the technology challenges are also intellectually fascinating in the extreme. But that is a bonus reward, not motivation.

What do you do in a typical day?

Weighing things involves measuring velocities – Doppler shift (radial) velocities from the ground. So a very large part of what I do is collecting that information. Then I think. Look for patterns. Test out models using mathematical calculations. Try out ideas. Read the literature, to keep perspective, so I can focus on the key big-picture stuff. Tossing ideas about with clever people I find very productive – trying to explain a half-formed idea to a very smart sceptic is the main way I do research. Almost always they show me why I’m wrong. Then we start again on the next idea.

I also spend significant effort on public talks, discussing the big ideas, the nature of existence, the meaning of meaning, ..  I am fortunate to be able to spend lots of time thinking about fascinating issues. The people who support this work are as fascinated as I am by it, and deserve the opportunity to hear from we who do it.

Are there any other interesting aspects to your work?

My job is fascinating at many, many levels. Big international projects involves intriguing politics.  It involves managing staff, which is easy since they are so smart and motivated, but is an interesting challenge given real-world resources. The ground-based telescopes I use are on mountains far away – Chile, Australia, Canary Islands, ... – using ultra high-tech kit on mountain tops is awesome. And humbling. Working at the interface between 'classical' astronomy and elementary particle physics – the dark matter – provides enormous intellectual stimulation. I find feedback after public talks especially stimulating. Perhaps the aspect I least expected to find so remarkable is the space industry engineering. That is simply awesomely impressive! Those guys and gals are just so smart.

What is it about your job that fascinates or inspires you?

I’m lucky to be able to do what lots of people would enjoy. Many –probably most -  people are fascinated by wanting to understand what we can see. The Milky Way being the classic example. Nature being what it is, to understand we have to think rather carefully about what we can see, and why we can see it. The obvious example everyone puzzles over is time – we can’t see it, but everyone thinks about it, and eventually gets to appreciate (and often re-invent) relativity. To understand the Milky Way we need not only relativity, but also dark matter – what you see is not what you get.

Why is what you do important?

Hey! Amazing challenge! How could that not fascinate?

At a very top level, I push the limits of knowledge, and motivate projects – like Gaia – which push the limits of technology. I do what is called 'basic' science, which at face value has huge short-term value, in exciting and motivating the public, and raising the content of our culture’s awareness of our place in the Universe. Like an unusual zoo animal. But we get back even more: history shows that  long-term technology advances follow advances in basic science – sometimes soon (computers), sometimes slowly (electricity). In space science we get the best of both worlds. While I am pushing the limits of reality, the space science technology community – much smarter people than me – are already pushing the limits of technology.  Building something as sophisticated as Gaia advances technologies in fields from imaging to precision measurements relevant to nanotech. Society will make both a cash profit and an intellectual profit from Gaia. I’m honoured to be a small part of making that happen.

What advice would you give to someone considering a career in space?

The trivial answer is that the language of the Universe is mathematics – so stick to the STEM! Real day-day work involves engineering, computing, physics. Get good at those, and the world is your oyster. I’m not sure I am a valuable role model to anyone, actually. I didn’t get  into what I am doing by planning – I am an astronomer by accident, not design. I think the most important thing is one’s approach to life – focus on what you find challenging. Don’t take the easy option, or the easy option will suck you down. You have only one life – make sure you spend it doing something which delivers self-respect. That is actually more important than a salary. Space science certainly delivers intellectual self-respect. And, sometimes, even a salary.


UK Space Agency

UK Space Agency

The UK Space Agency is an executive agency of the Government of the United Kingdom, responsible for the United Kingdom's civil space programme.

This article contains public sector information licensed under the Open Government Licence v3.0.

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