I photographed Susan Clark at Stanford in November 2024. The portrait sits in deep shadow, her face emerging from the dark with a quiet intensity, hands gently holding an ancient-looking armillary sphere. The sphere, a model of celestial order, feels apt, not for its historical astronomy, but for the way Clark’s own work reveals the hidden structure of the universe, drawn not in brass rings but in magnetic fields and interstellar dust.
Clark is an astrophysicist whose research focuses on the vast and turbulent medium between stars. This space, the interstellar medium, isn’t empty. It’s filled with dust, gas, and magnetic fields, and for decades, it was considered more a nuisance than a subject. Astronomers viewed it as visual interference, something to filter out in the search for cleaner cosmic signals. But Clark saw the foreground as a frontier.
Her work has changed how we understand galactic dust and the polarized light it emits. Using sophisticated data analysis and deep physical insight, she showed that this polarized light isn’t just noise, it carries a signature of the magnetic scaffolding of the Milky Way. These magnetic fields influence the formation of stars, regulate the motion of gas, and shape how we interpret the earliest light in the universe.
This matters deeply for cosmology. The cosmic microwave background, a faint radiation from just after the Big Bang, is one of the most important clues we have about the origins of the universe. But to see it clearly, scientists must first subtract the light scattered by dust in our own galaxy. Clark’s research has made that subtraction smarter. She’s mapped the galactic foreground with unprecedented precision, allowing cosmologists to see further and more cleanly into the beginning of time.
There’s a certain elegance to her work, a fusion of physics, astronomy, and computation that brings clarity to the chaotic. In some of her most striking visualizations, the dust of the galaxy flows like smoke caught in a current, tracing invisible magnetic fields that wind through space. It’s both science and a kind of cosmic cartography, sketching out the unseen shapes that govern the structure of the sky.
When I look at the portrait now, I think of that, of the stillness of her expression and the dynamism of what she studies. Magnetic fields, dust, light, and time. The space between stars turns out to be anything but empty, and Susan Clark is among the few who can read its patterns.
