Exoplanet Research: Searching for Life Beyond Earth | Laura Kreidberg Interview

Heidelberg, Germany – Perched above the historic city center on the forested Königstuhl hill sits the Max Planck Institute for Astronomy. A cornerstone of Germany’s academic landscape, Heidelberg boasts two universities and a dozen research institutions, with the Max Planck Institutes serving as the nation’s independent vanguard of scientific exploration. It is here that Laura Kreidberg (born 1988) leads a department dedicated to the study of exoplanets – planets orbiting stars beyond our sun.

Kreidberg has been instrumental in several breakthroughs over the past decade, including compelling evidence of clouds on a so-called “super-Earth” and the detection of carbon dioxide in an exoplanet atmosphere, a significant early achievement of the James Webb Space Telescope (JWST). Just under four years after completing her doctorate, she received an offer from Heidelberg that she couldn’t refuse – a rare combination of time, resources and academic freedom as a Max Planck director. “It was an offer I simply couldn’t turn down,” she says.

Her research focuses on the atmospheres of distant worlds, leading to the inevitable question: when will we find life beyond Earth? Kreidberg approaches this monumental task with a measured perspective. “I’d like to understand that myself,” she laughs. “But you have to learn to walk before you can run. The search for life is a sprint – and we’re not there yet. Right now, the field is focused on more fundamental questions: do rocky planets even have atmospheres? And if so, what are they made of? Those are the first steps.”

These atmospheres are primarily investigated using transmission spectroscopy, a technique where the light from a star is filtered through the thin gaseous layer surrounding a planet as it passes in front of it. This filtered light is then captured by a telescope and analyzed, revealing the chemical fingerprints of the molecules present. Currently, the James Webb Space Telescope (JWST) is the most powerful instrument for this type of analysis.

What the James Webb Telescope Can Reveal

What realistic expectations should we have for the coming years with JWST? Kreidberg believes the telescope will provide greater clarity regarding planets orbiting M-dwarfs – small, cool stars. However, she notes that finding true “Earth copies” around sun-like stars will require the next generation of telescopes.

The Trappist-1 system, consisting of seven rocky planets orbiting an M-dwarf 40 light-years away, is a key focus of current research. A major JWST campaign is underway to determine whether Trappist-1e possesses an atmosphere and, crucially, if it resides within the habitable zone – the region around a star where liquid water could potentially exist.

Is the intense focus on Trappist-1 justified? “Trappist-1 is a blessing and a curse,” Kreidberg explains. “As a system with multiple planets, it’s ideal for observations. But the star, like most M-dwarfs, is active and variable, making it tricky to distinguish between light from the planet and light from the star itself. We need to be careful not to put all our eggs in one basket, as there’s no guarantee the Trappist-1 planets have atmospheres. A diversified approach is needed – detailed study of a few well-observable planets, combined with observations of a wider range of worlds to gain a broader understanding.”

Beyond Trappist-1: The Rocky Worlds Program

Kreidberg is particularly enthusiastic about the Rocky Worlds program, which dedicates 500 hours of Webb telescope time to thoroughly investigate rocky worlds. One candidate she’s personally excited about is LHS 1140b, a relatively heavy, cool planet within the habitable zone of its star. This planet lies near the “cosmic coastline” – an unproven boundary where planets can either retain or lose their atmospheres. “It appears to be just on the ‘atmosphere side’ of that boundary, but we don’t have certainty yet.”

Transmission spectroscopy will remain a dominant technique in the field for the next five to ten years. Beyond that, Kreidberg anticipates direct imaging – obtaining actual photographs of planets alongside their stars – becoming the primary method. This will require larger telescopes, both on Earth and in space, with larger mirrors capable of separating the faint light of a planet from the much brighter light of its star.

Science and Politics: A Growing Concern

As an American scientist now working in Europe, Kreidberg expresses concern about the political climate in the United States. “I’m afraid. The developments are worrying. It breaks my heart to notice my country heading in an anti-scientific direction. That’s precisely why we must remain vigilant and participate in the political process. Scientists need to continue communicating with the public and explaining why this function matters. Science benefits society in so many ways – directly and indirectly. It’s, relatively speaking, a small government investment with an enormous return. Astronomy is one of the most accessible and inspiring forms of science. We have no political agenda; we are simply trying to understand the universe.”

Does Europe feel like a safer haven? “At the moment, yes. But I’ve seen how quickly the situation in the US changed. That could happen here too. What appeals to me about Europe is the stability: large projects like the CERN particle accelerator and the Extremely Large Telescope proceed with confidence and long-term funding. Europe is strong in building such infrastructure.”

Kreidberg as well highlights the improved work-life balance she’s found in Europe. “I work fewer hours than I did in the US and feel my science is more creative due to the fact that I’m less burned out. Here, it’s normal to abandon your work at work and enjoy your evenings and weekends. You don’t have to be constantly chained to your desk to do fine science.”

As a member of a new generation of female Max Planck directors, traditionally held by men, Kreidberg notes a positive shift. “In my student days, I was sometimes the only woman in the lecture hall. Now, my department is roughly fifty-fifty. That feels normal. You feel less like an outsider and can simply focus on your work.”

After six years in Europe, Kreidberg reflects on what she’s brought from American culture: “The idea that you should think large. That you shouldn’t list all the reasons why something can’t be done, but look for ways it can. Optimism, then. And hustle.” She smiles. “Let’s get this done.”

Looking Ahead

The search for habitable worlds and, life beyond Earth, remains a long-term endeavor. Kreidberg’s work, and that of her colleagues, is laying the crucial groundwork for future discoveries. As new telescopes come online and data analysis techniques improve, our understanding of exoplanet atmospheres – and the potential for life they may hold – will undoubtedly deepen. The next few years promise to be a pivotal time in this exciting field of astronomical research.

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