Sam Geen

Thanks guys! You are all amazing. Project details coming soon...

Favourite Thing: (Note: Favourite thing *in science*) I love coming up with new projects. It’s much easier to come up with cool ideas than it is to finish them.



Chandag Junior School in Keynsham, then Prior Park in Bath, then Oxford University in Chelmsford


A buncha GCSEs, A-levels in Physics, Maths, Further Maths and Latin (which was awesome but which I have forgotten almost entirely. Sorry Mr Holland!) a masters degree in Physics, then a doctorate in Astrophysics. I probably have my old swimming certificates somewhere, too.

Work History:

Other than research, I’ve done some summer jobs working with sonar systems at a company in Bristol.

Current Job:

I’m a postdoc (i.e. someone who’s finished their PhD and is bouncing around institutes every few years)


The Observatoire de Lyon. Well, technically the French Atomic Agency. Well, technically the European Union. Academic funding is weird.

Me and my work

I run computer simulations on supercomputers of the gas inside galaxies to try to understand how stars and galaxies are made.

A galaxy is a bunch of gas and stars. It’s also made of dark matter, but let’s not go there just yet. What’s over there? A squirrel? Ah no, it was just a branch. Oh well.

The gas in a galaxy is mostly hydrogen, with some helium and a small amount of other elements. It’s turbulent and messy, stirred up by a variety of things going on inside the galaxy. When clumps of gas come together in this turbulent mess, they begin to collapse under gravity. These clumps eventually form smaller clumps, which can collapse to form stars. Most of these stars are small and rubbish and don’t do much. Some of these stars are like our Sun; medium sized in the grand scheme of things. A few of these stars are much larger than our Sun, however. Bigger stars lead short, violent lives, pumping out winds travelling at thousands of kilometres per second, bathing the space around them in ultraviolet radiation, and eventually exploding as supernovae. All this messes with the gas around them – blowing away gas that might have formed stars, creating shockwaves that blow huge bubbles in the galaxy, even blasting gas out of the galaxy itself. This problem is very difficult to understand; it’s like trying to forecast the weather if gravity moved in all directions, temperatures went from near absolute zero to tens of millions of degrees, and winds could blow from one side of the Earth to the other in a few seconds.

My job is to use supercomputers to understand all of this. Previously I used a simulation of a galaxy like the Milky Way that took millions of hours (in total) on thousands of processors and Terabytes of data to try to understand what happens to all the small galaxies that should be orbiting our galaxy, but apparently are missing. Now I’m working on a project where I put a simulated star in the middle of a box full of gas and try to figure out what happens – watching the ultraviolet radiation heat up the gas, the stellar winds blow outwards, and finally the supernova ripping through it all. The eventual goal of my work is to understand exactly how the insides of galaxies work, and the complex relationship between stars and the galaxy they live in.

My Typical Day

I program supercomputers, read research papers and talk about bananas in French.

A terrible, depressing truth is that astronomers spend most of their time sitting at computers sifting through data. This counts doubly for people like me, who don’t even use telescopes but call themselves astronomers because calling yourself an astrophysicist at parties is code for “don’t talk to me”.

I go to work by bus, and then walk up a huge hill because building observatories in flat places that are easy to get to apparently isn’t cool. Occasionally I meet the observatory warden and we talk about peaches and bananas (this is a thing). When I arrive, I put my stuff down, wander up to the kitchen area and check my regular mail (which usually contains a huge amount of junk mail from the French atomic agency marked URGENT). I then check my e-mail, my b-mail, my q-mail and yes ok those are not real things, webcomics and Rockpapershotgun, which are real things. I then log into the supercomputer in Oxford (part of the STFC DiRAC facility), and type “st” to see who is blocking me out by using five hundred processors at the same time (YOHAN). I tend to do most of my work on this computer as I curently have 10TB of data, which makes my laptop sad if I try to copy, store and process it on there. So much of my time is spent typing into a terminal that is open on a machine a thousand miles away and I should stop trying to reference The Matrix because it just makes me look old. If I’m running simulations (hello, re-railed train of thought), I check that they’re going OK and haven’t started making weird squares again (this took me weeks to figure out). If they’re done, I try to analyse it by writing programs that reduce all that data into simple images or 1D plots that describe what’s happening in them (I use Python, which is super nice and you should try it. TRY IT.) If this is done, then I write a paper that puts it all together, which is probably my least favourite thing and which I procrastinate continuously on (more brackets! MORE.) Otherwise, I spend a lot of time reading papers – either (I don’t read them all, as I’m not insane) or papers from the 1970s written by people who I’m sure are some kind of algebra wizard or warlock or sorceress or whatever.

Eventually, I get tired or hungry or have some kind of music thing in the evening, so I flop down the hill and catch the bus, where I listen to kids shout JE TE JURE JE TE JURE at each other.

What I'd do with the money

How does making your own galaxy and then flying through it in 3D with VR goggles sound?

If I win, I’m going to write a program that allows you to make your own galaxy and fly around it in 3D. One of the thngs that got me into science was putting all those dumb equations into Javscript (which I was using to write stupid webpages) and seeing stuff fly around in real-time. I’d spend the money on computer hardware and web space, possibly visiting schools to try it out or opening an Amazon web server to let people who have sucky computers try it out for themselves.The Oculus Rift is an upcoming Virtual Reality headset, and it’d be really cool to allow people to fly through their galaxy in full 3D. Your votes can help you become a Virtual Reality Galactic overlord!

Another fun thing might be to buy 50,000 one penny sweets to run a demonstration on how sick you can get, and I will not be doing this.

Man no OK I am totally doing that.

Yeah, no I’m not.

My Interview

How would you describe yourself in 3 words?

Hi, I’m a

Who is your favourite singer or band?

Naragonia (Belgian folk band, and yes, but this is amazing and if you disagree then don’t worry it is OK to be objectively wrong from time to time:

What's your favourite food?

There are some amazing cakes in the bakeries here in Lyon

What is the most fun thing you've done?

Possibly not the *most* fun thing, but the party at the AAS conference with 2000 astronomers in a Seattle gay club was pretty entertaining.

What did you want to be after you left school?

I dunno. I’ve sort of stumbled into things I thought sounded interesting or useful to know. Doing an astronomy PhD was a last minute decision, and one I haven’t gone back on just yet.

Were you ever in trouble in at school?

Not really. I was a pretty quiet kid. This usually means that if you do do something wrong, you don’t get in a whole bunch of trouble for it. Heh. I did get chased by a farmer for launching fireworks at 4am, but in my defence that was someone else’s terrible idea.

What was your favourite subject at school?

Man, I dunno. Not-sports, I think. I was a little husky, if we’re being charitable.

What's the best thing you've done as a scientist?

I visited Korea with my research group, which was pretty amazing.

What or who inspired you to become a scientist?

I was always interested in space, and both my parents were scientists (well, a sonar engineer and a medical doctor). I also played way too many videogames as a kid, and learning game programming was possibly my gateway into computational astrophysics.

If you weren't a scientist, what would you be?

A moustachioed jewel thief. Or something to do with computer programming. I like playing music, but I’m too lazy to practice.

If you had 3 wishes for yourself what would they be? - be honest!

Honestly, aside from obvious ones like world peace, etc, my life is pretty sweet. I mean, it would have been nice if my mum didn’t die of multiple sclerosis, but I don’t know if you can unwish that kind of thing. I should ask the Département de génie.

Tell us a joke.

Smoothed-particle hydrodynamics. Or, well, OK, so you can tell ducks are baryonic because they’re always going quark quark quark.

Other stuff

Work photos:

In my day the internet was all like BEEP BEEP BRRRRP and then it would stop when your mum picked up the phone. We also ate coal instead of sweets and had to go down the mines to earn our families tuppence so we could buy gruel. Now you can see pictures from across the world on glowing squares and they have birds which are angry at pigs for some reason and I don’t understand anything any more. Here are some of those pictures. Blat:

This is me by the entrance of the place I work:

Walking down to my office. Try turning your head left for optimal viewing discomfort.

My desk. My awful camera skills seem to have artfully cropped out most of the towering pile of crud heaped up around it. The two monitors were there when I got here and I’ve never used them. Cathode ray! Yeah. Now we’re cooking with 1990 etc etc.

The telescope domes (only used by students now; the proper telescopes are all huge and on the top of mountains). Getting photobombed by a tree is super embarrassing because they’re really slow but this one was all ninja wow.

It’s an old telescope! Exclamation mark! It was built in the 1800s. The telescope sticks out of the obsevatory building so the astronomer can sit inside in the warm and not get pneumonia and die like astronomers usually did back in the day. Also the weather here is super nice at the moment you guys, though it sucked right up until this week and I was all like WHAT IS THAT GIANT YELLOW THING so I guess swings and roundabouts.

Oh wait yeah I study stars so I should have known what that giant yellow thing was. Anyway. Here’s a lot of toilet paper delivered to the building. I took a picture. Sideways, apparently (there’s some tag in the jpeg format that rotates it but the website is all like YOUR PUNY IMAGE FORMATS ARE NOT RECOGNISED IN IMASCIENTIST.ORG.UKLAND man I should probably get some sleep close bracket).

The view from behind the observatory, looking over orchards and hills. The building in the middle there is a restaurant school where you can learn to be a restaurant. I think that’s how it works.

A picture of a galaxy simulation I wrote my PhD thesis on. The colours are the gas, zooming in on the main galaxy. The grey is the dark matter, and the red is the stars. I’ll explain what all this means in the questions.

The simulations I’m using now. This shows the density of the gas when a supernova goes off and blasts into the space between the stars (called the “interstellar medium”).

Un pamplemoose.