There’s one question I’ve been asked quite often these past few months, whenever I talk about my latest work and the PhD I’ll be doing for the next 3 years. Lately, I’ve been asking it myself too.
random person, my dad, me
I have a simple question: Why Jupiter?
Except… it’s probably not so simple. I often have to ask for clarification, or check whether I’ve interpreted the question right. It can be about me, or about all of us: why do you study Jupiter, or why do we, as in humanity, study it at all? Often it’s a bit of both.
Caption
Jupiter in visible light, as seen by Hubble on 19 May, 2017
Philippe Huneman, in Why? The Philosophy Behind the Question, retells an old joke: a bank robber is asked why he robs banks, and he answers, “Because that’s where the money is.” The joke works because he’s answering why banks, rather than grocery stores? when the person asking meant why rob, rather than work? Why-questions often hide a rather than, and which one is meant depends on who is asking.
So “Why Jupiter?” is really three questions, though they don’t split neatly between the three people in the quote above. A random person usually means why Jupiter, rather than something useful? My dad means that too, but also why Jupiter, rather than something safe? That one I ask myself as well, along with a third: why Jupiter, rather than anything else?
Rather than something useful?
From a random person, and from my dad, the question is really about research in general. Why do scientists study Jupiter at all? What is it for? What difference does it make to the average human life on Earth? Who cares about the collapse of molecular clouds, or the effects of Saturn’s rings on its moons, or the atmospheric composition of exoplanets light years away?
I have a practiced answer to this one. Jupiter is a giant natural laboratory of fluid dynamics, with extreme weather that we don’t get on Earth. Studying it with the physics we built for Earth shows us how far that physics stretches, where it breaks down, and what we need to add or change to explain a new system. Or, as a planetary geologist puts it:
Mathieu Lapôtre ( Stanford Report, 2020; see also Lapôtre et al., 2020)
We don’t only look at other planets to know what’s out there. It’s also a way for us to learn things about the planet that’s under our own feet.
The other half of my answer is that nobody can tell in advance which detours in our pursuit of knowledge will turn out to be useful. When Mariner 9 reached Mars in 1971, the planet was hidden under a global dust storm, and the spacecraft found the atmosphere warmer and the surface colder than they should have been. Planetary scientists spent years working out how dust in an atmosphere does that. Some of the same people went on to apply that physics to volcanoes, then to the asteroid that killed the dinosaurs, and finally to the smoke and dust a nuclear war would throw into the sky, in the study that gave us the phrase nuclear winter (Turco et al., 1983). I still find it wild that a dust storm on Mars ended up there.
I sometimes wonder if that’s why we’re curious at all. Maybe we evolved a general curiosity because we can never tell which information will pay off. And so we gleefully stray into paths that sometimes lead to discoveries.
That’s the answer I give to other people, and it works for planetary science, or cosmology, or pure mathematics, or any STEM field with an ivory-tower reputation. I find the more personal versions of the question harder.
Rather than something safe?
My dad asks it a second way: why this, instead of a stable job?
To be honest, when I chose space science as my major, there wasn’t a speck of practical thinking behind it (my parents would totally freak out if they read this).
I had no idea what a research career would look like, and neither did anyone I knew. For most of my bachelor’s degree, family and friends back home gave me doubtful looks. I did look up the jobs this major might lead to in my country, mostly in satellite engineering, but that was more to convince my parents. I didn’t even want to become a satellite engineer. I lay awake at night worrying about unemployment, about becoming a disappointment and a financial burden to my family. And yet I somehow kept going. Part of that somehow was privilege. My parents covered my living costs during university so I could focus on my studies without juggling part-time jobs, which not everyone gets to do. Without that support, I doubt I could have afforded to ignore practicality in the first place.
Of course, luck like that can run out for anyone, so I’ve been torn ever since between chasing my starry-eyed ambitions and settling for something more realistic. Five years later, I have a much better idea of what I signed up for. I know what research and living abroad alone are really like, and how little job security there is in both academia and industry. I also know that opting out now with a master’s degree to join industry would probably be a better financial choice. But… I still cannot bring myself to choose a safer route if it means giving up the work I dream of: doing curiosity-driven research, without the need for immediate practical applications.
What made me so stubborn about a field with such poor job prospects, especially in my own home country?
Perhaps pride. Where I grew up, the way I looked, dressed and acted didn’t fit the usual mold for my gender, and some of the people closest to me never let me forget it. Anything below the very top of the class wasn’t good enough either, and I heard about it every time I fell short. So pursuing a strange, niche scientific field was my way of rebelling, of saying: I’m still gonna try something that’s not what you had in mind for me, just because it makes me happy, and I’ll do it well without having to be the best.
Perhaps the wish to take my mind to outer space, where there are no barriers, hierarchies or national borders. Studying the fluid dynamics of astronomical objects, something few people back home had heard of, turned out to be a ticket out in real life, too. It lets me work on something I enjoy while travelling to new places where I can unlearn the rigid ideas I myself had internalized about how people should look and behave.
But plenty of other paths would have let me rebel, and plenty of others lead out of a judgemental society. So why did I choose planets, of all things?
Rather than anything else?
The last version is mine alone: why is Jupiter interesting to me?
I remember being fascinated by rain as a kid (I still am, actually). Having lived in a tropical country most of my life, I loved the cool it brought. I loved the smell of rain-soaked earth, and watching raindrops splatter and trail down the windows. In high school, I found out that I enjoyed physics and wasn’t bad at it. There were also many books about space on the shelves at home, collected by my older sibling. I read them when I was bored, and the vastness of space started to fascinate me. Around the same time, I heard about a space science program in Hà Nội that taught both atmospheric science and astrophysics. That was when the thought popped into my head: do other planets have rain and storms too? What does the weather even look like in such alien environments?
Caption
A folded filamentary region captured by the Juno spacecraft on 15 April 2021. It began almost a year earlier as a storm called Clyde’s Spot (Palotai et al., 2023). Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin Gill.
They do, and their thunderstorms are oddly similar to ours in some ways and bizarrely different in others. On Jupiter, as on Earth, they are driven by water vapour condensing and releasing heat. But Jupiter’s air is mostly hydrogen, so air carrying water vapour is heavier than dry air instead of lighter, and something has to push it up before a storm can even start.
That’s my project now. I’m using a computer model with a grid fine enough to simulate individual clouds to study moist convection on Jupiter, meaning storms driven by condensing water: how strong they get, how often they form, how long they last, and what triggers them. We also want to see how these storms might affect the planet’s large-scale circulations.
From the outside, those large-scale circulations show up as Jupiter’s stripes, and its appearance drew me in too, though for a much more childlike, whimsical reason. It’s the kind of reason that scientists tend to downplay, as the mathematician Terence Tao points out:
Terence Tao ( Mathstodon, 2026)
… perhaps in order to impress the other adults observing (and, through public funding agencies and the like, financially supporting), we often downplay the “childish” aspects of the craft, in favor of the more tangible “serious” outcomes — including the hard, objective target of solving some designated open problem.
So here it is: I find the colours and patterns of Jupiter pretty. Earth from space is mostly blue, white and green, but Jupiter is striped in cream and rust, and along the edges of the stripes, the cloud patterns curl into long, feathery plumes and eddies. Its two hemispheres don’t even mirror each other, and the Great Red Spot has no twin in the north. At the poles, the stripes fade into a bluish, blotchy zone of cyclones. They crowd into rings of eight (in the north) and five (in the south) around each pole like petals of a flower. I wondered why the planet is striped, what gives the stripes their colours, why they don’t mix, and what goes on underneath the clouds we see.
Caption
Jupiter’s south pole, combined from JunoCam images taken on two passes, 27 August 2016 (left) and 2 February 2017 (right). Credits: NASA/SwRI/MSSS/Gerald Eichstädt/John Rogers.
Some of those questions have at least partial answers by now, but not all of them. The darker stripes are belts and the white ones are zones, and nobody is sure yet what gives the belts their reddish-brown colour (Ribeiro et al., 2025). It’s not even clear anymore that the white clouds are made of ammonia ice, as textbooks say (Irwin et al., 2025). Juno also found that deeper down, around where the water clouds should form, the pattern of belts and zones flips (Fletcher et al., 2021). The clouds suggest that air rises in the zones, but the winds suggest it sinks there, and that contradiction goes back decades (Fletcher et al., 2020). A recent paper proposes a way to reconcile the two (Mendonça et al., 2026), but even its authors say it can’t yet explain everything Juno found.
Maybe that’s part of the pull: a planet full of problems nobody has fully solved yet. And whether or not the problems get solved, I know for sure that I enjoy the journey of doing research itself. The tinkering, the failed attempts, the moment something finally clicks, even the deflating moment of realizing the approach you spent weeks or even months on was wrong and you have to back out of it. Trying to understand something feels worth doing for its own sake, not just for the destination it leads to. You can always ask what a goal is for, and then what that is for, but at some point the chain has to end in something wanted for itself (right?). Mine seems to end in curiosity.
Jupiter, for now
How I actually got here was a series of detours. During a meteorology course in my master’s program, I got interested in gravity waves, which ripple through the atmosphere a bit like waves on a pond. So for my first master’s internship, I looked for a researcher working on gravity waves on other planets, and found one in Germany. His proposed project wasn’t about gravity waves, though. I spent the semester working on hydrogen escape on Mars instead, but I really did enjoy it. My supervisor in Germany suggested I consider gas giants for my next projects, since they are still not as thoroughly explored as Mars. That’s a practical reason, and I do agree with it. But to a meteorology enthusiast, giant planets made almost entirely of fluid with extreme weather are already just so alluring in themselves, with so much to look at, so many questions to ask, and so many winding paths to wander down. And so for my master’s thesis (which has now turned into a PhD), I looked for groups working on gas giants in France, since I didn’t want the hassle of moving to another country again this year. That’s how I ended up simulating storms on Jupiter, for the next 3 years at least.
Perhaps Saturn and its rings and moons come next. Exoplanets are tempting as well. Or maybe one day I’ll come back to molecular clouds, something I worked on during a summer internship.
Who knows, it doesn’t even have to be physics forever. I can always take another detour.