Kumiko Kotera

Kumiko Kotera’s first dream was to become a writer. But as destiny would have it, she found her true calling in astrophysics. The first female director of the Institut d’Astrophysique de Paris at the age of 42, Komiko decided to honour her childhood dream and publish her first book, L'Univers violent (The Violent Universe). In her writing, Kumiko shares her vision of the cosmos in its relentless upheaval and marked by extreme phenomena, alongside her daily life where science and human adventure are deeply intertwined.

A path connecting prose and the sky

Her universe could have been made of paper. Her story could have been completely different. For a long time, Kumiko Kotera thought that her life would revolve around writing. “I always cherished that dream, and even after becoming an astrophysicist, I never completely gave up on it,” she confides.

Born into a Japanese family in France, Kumiko was immersed in literature and science throughout her childhood. Her father, a chemistry researcher at the CNRS, passed on his love of discovery. “But it was never a question of following exactly the same path as him,” she explains. The poetical and metaphysical dimensions of astrophysics seemed to her like the obvious choice. After two years of preparatory science classes, she enrolled at ENSTA Paris, completed her Master's degree and PhD, before flying off to Chicago for a postdoctoral position.

In Chicago, Kumiko met Angela Olinto, an astroparticle physicist and current provost of Columbia University. “A brilliant woman and pioneer in her field, both strong and kind,” says Kumiko. As the first female professor in the physics department at the University of Chicago, Angela Olinto became a role model. “She helped me reconcile with the idea of being a female scientist, both respected and yet true to one’s values and oneself. It was a revelation. Until then, I had only had male supervisors, whose intuitions were very different from mine. I lacked a role model with whom I could identify.” Ever since, Kumiko has kept this compass: "When faced with a difficult decision, I ask myself what she would do. Her example continues to inspire me," she smiles.

The violent universe: a scientific and human adventure

The study of the universe, a theatre of extreme events where black holes, gamma-ray bursts, and stellar collisions rage, has been Kumiko Kotera’s predilection since her thesis. Now an astrophysicist, her work focuses specifically on cosmic rays. These ultra-energetic particles from the far reaches of the cosmos carry clues about phenomena in the universe. “We know they exist, but we still don't know where they come from,” she says. To unravel this mystery, she turns to a secondary messenger: neutrinos. Unlike cosmic rays, which are deflected by magnetic fields, these particles travel in a straight line, providing a direct trace to their source. “That's what makes them so valuable in our quest to understand the violent universe.”

GRAND, a window into the violent universe

A few years ago, this research gave rise to GRAND (Giant Radio Array for Neutrino Detection), a titanic project that Kumiko currently coordinates. The project consists of a network of antennas deployed in remote areas to detect cosmic messengers. “We want to open a window onto the violent universe,” she says enthusiastically.

In the Gobi Desert, 46 antennas are already scanning the sky, soon to be joined by a hundred more. The next phase, in Argentina, will mark a change of scale, with the ambition of detecting very high-energy neutrinos. This is a major leap in astrophysics, and its potential results are already being described as ‘Nobel Prize-worthy’.

Supported by Sorbonne University, the GRAND project brings together 145 researchers from 12 countries, with a strong European component and Chinese involvement. “Despite tensions around the world, science offers a means for creating bonds and rising above divisions. It represents one of the last frontiers of international diplomacy and cooperation,” Kumiko emphasises.

At the helm of the Institut d’Astrophysique de Paris

As head of the Institut d’Astrophysique de Paris (IAP), Kumiko Kotera is committed to cultivating the pioneering ethos of this institution, born from the convergence of astronomy and modern physics. “With the support of Sorbonne University, we are developing new digital methods to analyse and simulate the masses of data generated by major exploration projects, producing a new dialogue between theory and observation,” she explains.

Astrophysics has changed scale since the joint detection of gravitational waves and a gamma-ray burst in 2017. Kumiko explains: "we can no longer observe the sky solely through light. We must take all cosmic messengers into account. With the support of Sorbonne University and in particular the LPNHE, the IAP is engaged on several fronts: photons, gravitational waves, cosmic rays, and neutrinos, with large-scale projects such as SVOM, LIGO-Virgo, LISA, and GRAND."

Kimiko has a tightly organised schedule in order to carry out all her activities: mornings are for managing the IAP; afternoons are for research; and nights are for writing. Her day includes a non-negotiable break at 4:30 p.m. to pick up her children from school.

“I've found a balance,” she confides. “Working collectively is also a source of satisfaction. It's not a duty, it's a necessity,” she insists. This sense of community is deeply rooted in her Japanese heritage. “Perhaps my dual culture gives me a different perspective on scientific cooperation and collaboration. I am immensely grateful to all the people I work with and who support me in my career and my life. It's something deeply ingrained in me, and I think it's quite Japanese.”

Fieldwork: an open-air yet confidential environment

One of the moments when scientific collaboration becomes a true human adventure is during fieldwork. Set in an open-air yet concealed environment, three hours from the nearest town in the Gobi Desert, the GRAND project is taking shape. "It's not just about the universe, it's also about the human experience. We're there, with our antennas, waiting for signals from the cosmos, in sometimes spartan conditions," explains the researcher, recounting her latest expedition.

Out there, everything depends on preparation and patience. "I love the idea of being overwhelmed by what we observe, of waiting while meticulously preparing what will allow us to explore this violent universe. The constant vigilance, the total readiness for whatever may arise, is what excites me. In our field, cosmic events are fleeting. You have to be ready to capture them, to understand them as they happen. Ready for the unexpected, for upheaval. Ready for joy, too. And that takes preparation."

Preparation for fieldwork doesn’t simply require writing equations. It means adjusting, tightening and relaunching the system. "Quite often, things don’t work the first time. We test, we start over, again and again. And then, after repeated attempts, it works. And it's wonderful." In the afternoon, some of the researchers adjust the antenna communication and others analyse data flows. As evening falls, the temperature drops drastically. “We squeeze eight people into the pick-up trucks to go home. Driving on the backroads is an adventure in itself. After dinner, we catch up on emails, manage the finances, and analyse the data collected that day.”

And then comes the moment, late into the night, when Kumiko Kotera goes out alone to the sky and lifts her gaze to the horizon. “It’s dizzying. A moment that exists outside of time, in the middle of the expanse.” It is this sense of vertigo that fuels her need to write. Every night, instead of succumbing to sleep, she fills her notebook. “The experience is so intense that I don’t want to lose anything. Everything must take shape through words, I must capture the essence of my experiences, as if just living isn’t enough.” Her first book, L'Univers violent (The Violent Universe), in which she shares the human and scientific adventure of her research with her readers, was born from this necessity,

“At first, I didn’t talk about it with my colleagues. I always kept the various aspects of my life neatly separated. Then one day, I had my ‘coming out’,” shares Kumiko. Writing, like research, became essential for her. She is convinced that sharing science - conveying both its excitement and capacity to surprise - with the wider general public is vital. “You can't do science without sharing it. It's one of the core missions of the IAP.”

She wanted her book to be vibrant, just like her research: a human adventure, far from the coldness and rigidity often attributed to research. “Science is built on exchange, discussions over coffee, bursts of laughter, and the walks where we reinvent the world,” she explains. “I wanted to write a book that conveyed the emotion and joy that one feels when doing research.”

Published at the same time as she took on the role of director of the IAP, her book is also the story of a woman in science. “The first chapter begins when I was pregnant.” This choice is far from insignificant: she recounts how her physicist friends often “carry several projects at the same time.” A science where motherhood is not a hindrance but a strength. “I have two children, and I think it's important to say that it is possible to have a family and a scientific career.” It is a reality that is rarely mentioned, but nevertheless essential in her eyes.

Today Kumiko has become a role model, almost in spite of herself. "I am very honoured to be a role model and an inspiration for young girls who want to pursue science. Because I know how much it meant to me, and how much I lacked role models."

From the young girl who dreamed of writing to the researcher who studies the universe, Kumiko Kotera no longer chooses; she embraces both. Cosmic exploration and writing are a mutually enriching process. At the crossroads of cutting-edge research, science outreach and institutional responsibilities, she embodies a new generation of astrophysicists who, like neutrinos, overcome obstacles without ever deviating from their trajectory.

Portrait written by Justine Mathieu