Oh, getting ready to take part in some chats. It's been a little while, hope my typing skills are fast enough.
EducationI went to Lancaster University and got a MPhys in Physics with Particle Physics and Cosmology and then I went to Queen Mary University of London and got a MSc in Astrophysics. I'm currently at the University of Southampton working on getting my PhD.
QualificationsMSc, MPhys, A-levels, GCSEs
Work HistoryBefore my PhD I've done all sorts. I was a paper girl, I've cleaned toilets, I've worked in a shoe shop, I've worked in a pub.
Current JobPhD student
University of Southampton.
Favourite thing to do in my job: Learn about the dust close to supermassive black holes
About Me: A UK/US dual national at the University of Southampton. My life is dust.
My name is Bella Boulderstone (she/her), I’m a PhD student at the University of Southampton. I’m a dual UK/US national. I’m 27 years old. I like badminton, Eurovision, feminism, Star Trek, David Attenborough nature documentaries & the NFL team the 49ers. I have a 1174 day streak (as of 11/03/2020) on Duolingo (I’m trying to learn Spanish). I’m currently training for my first 10k, which I expect will be exceptionally slow.
My Work: The dust around supermassive black holes
So, at the centre of most galaxies lies a supermassive black hole. This is a lot of information to take in and usually prompts a few questions:
- What is a black hole?
- What happens when I fall in one?
- Just how big is supermassive?
And those are pretty good questions. Here are some answers:
- A black hole is essentially a hole in the fabric of spacetime. Which also, is a lot of information. If you imagine that all of space is some big stretchy fabric, then all the planets and the stars and the galaxies sit in what are called ‘wells’, like a dimple. The size of the space dimple (or well) is dependent on how much stuff there is in it – how much mass it has. The way we (as humans) see the Earth’s space dimple is as gravity. Everything that is made up of stuff, has gravity associated with it.
Great. So everything travels on this stretchy dimply space fabric stuff. Even light itself travels along this stuff. Now imagine, that there’s something on the fabric that is so heavy, that things can’t even escape from it. That there’s a hole in this dimply stretchy spacey fabricy stuff.
That’s a black hole. They’re objects that are formed by huge exploding stars (supernovae) which leave behind a central core where nothing can escape. But things do rotate around black holes, and that’s important
2. What happens if I fall in one?
Ok, so you’re an astronaut and you see a black hole and you go, ‘Hey, it would be great if I were to take a quick trip to a black hole, what could go wrong, right?’ WRONG. So many things could go wrong!
You end up as spaghetti. Or, spaghettification, real scientific term for what happens to you if you decide to take a trip to a black hole. You get spaghettified. Which is exactly what it sounds like. If your fellow astronaut watched you as you fell into the black hole, that’s what they’d see.
3. Just how big is supermassive?
Well, a ‘small’ black hole can be 5-10 times the mass of the sun and a ‘supermassive’ black hole can be a million times the mass of the sun. So there’s quite the range. It’s worth noting that the sun’s mass (how much stuff the sun is made of) is about 100000000000000000000 kg. Which is so heavy, it doesn’t really bare thinking about.
But this isn’t really the bit that I do. So, at the centre of these galaxies, the black holes hang out and they can grow by stuff falling into them. This is called accreting and produces a lot of energy around the black hole (Not coming out of it, nothing can come out of a black hole). This stuff that’s falling into the black hole forms a flat disc structure (like a CD, if those even still exist anymore) and swirls around the black hole until it eventually falls in. Being ripped apart and spinning fast and all sorts. This flat hot, spinny bit is called the accretion disc.
The famous picture you may have seen recently of the black hole shows the black hole at the centre and the accretion disc:
Ok, so we have the black hole, and the accretion disc, I gotta do one of these things, right? Sorry!
So, outside of that, there’s some dust. It acts as a way for all the stuff in the galaxy to funnel onto the accretion disc so that it can funnel into the black hole. It’s in a sort of donut shape, but if the donut was made of a lot of little dust clumps.
The inner edge of this donut is set by the dust sublimating – turning straight from a solid into a gas like dry ice. This happens at a specific temperature which relates to the infrared bit of the electromagnetic spectrum.
This dust absorbs the light coming from closer in and then re-emits it, just with a bit less energy. This means that all the variations in the light closer in will be seen in the light further out. Basically, the dust is creating a space echo.
And that’s cool, because then we can find out sizes. So speed = distance / time (the only equation I’ll use I promise) and we know that light travels at the speed of light (which is great, very handy) and we can find the time the light takes to echo, so we can find the distance the light travels to make that echo!
Why do we care about space echos?
So, space has this really awkward problem. How can you tell if something is small, dim and close or bright, big and far away? We work a lot on finding things that we can use as ‘standard rulers’ or ‘standard candles’. This is the ‘scale’ of the universe.
Like in this map of Southampton here, it has a scale so you know how far away things are from each other. That’s what we’re trying to find, the ‘scale of the universe’.
My Typical Day: Programming to find space echoes!
I do a lot of programming as part of my PhD.
I use the code that I write to look at the images that a telescope in Chile has taken.
I use these pictures to find the brightness of my objects in order to create lightcurves – watching how the brightness changes over time. I have pictures in visible light (like we see with our eyes) and infra red (like the heat vision).
Because visible light is emitted by hotter things and infrared is emitted by cooler things, if you see a pattern in the visible light and see it later in the infrared, it’s an echo. The light has been absorbed and then given out again, but colder. These space echoes are what I’m looking for.
This is the sort of thing. I do this to find the distance between the accretion disc and the torus as I probably explained above.
When I’m not coding, I’m going to a lot of seminars, which are just talks by other scientists. They talk about what they’re doing and you get to learn all about so much other stuff, which is really important because so many bits and pieces are interconnected in science. You might be really struggling with a problem that someone else has already solved!
Already this week I’ve been to a talk about objects called pulsars which are collapsed stars which pulse like lighthouses, sometimes thousands of times a second. They’re incredible. We have a lot of people in my department who work on supernovae – exploding stars. As well as that, there are a lot of people who work on trying to simulate the entire universe!
We also have to read a lot of papers – scientific publications about recent developments in our area (and others): https://arxiv.org/list/astro-ph/recent they’re really tough going! I usually scribble all over the papers that I find useful in order to read them better (I also try not to spill too much tea all over them!).
Another part of my work is related to my scholarship which depends on doing some teaching. I have to run problems classes (essentially help undergraduate students finish their homework!) and mark students’ exams. This can be really time consuming because you have to be really fair and mark the same all the way through the exam scripts! I have a lot of sympathy for people taking exams because I was never any good at them.
How would you describe yourself in 3 words?
Oh man, this is a tough one. Um, Tenacious, funny & excitable.
What or who inspired you to follow your career?
I think I really enjoyed the idea of learning as much as possible and physics seemed to be a good way to do that.
What was your favourite subject at school?
I really liked maths, I thought it was fun to see how everything moved from one step to another and it worked pretty nicely together. I also liked drama a lot because it lets you get really creative.
What did you want to be after you left school?
I'm not really sure, I don't think I had any real clear ambitions after leaving secondary school, I just wanted to do science.
Were you ever in trouble at school?
Absolutely. My friend bought me one of those plastic blow-up sofas for a birthday present and I insisted on inflating it right then and there. I took it around to all my lessons, my teachers were not impressed.
If you weren't doing this job, what would you choose instead?
I'd be an astronaut? I really love having adventures and I couldn't think of a better one than going to the moon (or Mars) or even living in the ISS.
Who is your favourite singer or band?
I'm a big fan of heavy metal, at the moment one of my favorite bands is called Clutch. I also enjoy some Iron Maiden. On the other end, I like Janelle Monae and David Bowie, their creativity is so impressive.
What's your favourite food?
Burritos. Or a bagel? I love katsu curry as well.
What is the most fun thing you've done?
On a conference I went to recently in Chile, I got to go white water rafting on a really beautiful tealy-blue river. The views of the volcanoes were pretty stellar but I got to jump of a little cliff into the water which was so much fun, I went and did it again.
If you had 3 wishes for yourself what would they be? - be honest!
1. No more global warming. I'd like the planet to be alright. 2. I'd like to go to Mars? Mars would be excellent. 3. I think I'd like to make it out of my PhD alive! These things are tough!
Tell us a joke.
A photon goes into a hotel and the person behind the desk says, 'Hello, would you like us to take your bags to your room?' and the photon says, 'No thanks, I'm travelling light.'