Life beyond Earth is the next big question: Nobel laureate Didier Queloz on exoplanets, AI and the future of science

Life beyond Earth is the next big question: Nobel laureate Didier Queloz on exoplanets, AI and the future of science

Olha Konsevych

The idea that other worlds may exist somewhere in the universe has troubled and inspired humanity for longer than modern telescopes have existed. Every new discovery seems not to bring us to final clarity, but to push us toward deeper questions. In cinema, a good script is enough. In science, there must be evidence.

In 1995, Swiss astronomers Michel Mayor and Didier Queloz announced the discovery of 51 Pegasi b – the first confirmed planet orbiting a star similar to the Sun. Twenty-four years later, Mayor and Queloz shared half of the Nobel Prize in Physics for that discovery. The other half went to Canadian-American cosmologist James Peebles for theoretical discoveries in physical cosmology.

51 Pegasi b was not the “second Earth” that popular culture so often imagines. It was a gas giant, extremely close to its star, with a year lasting only a few Earth days. But precisely because it was so unexpected, it changed astronomy.

Nearly three decades later, Queloz says the question has changed. Humanity no longer needs to ask whether planets exist around other stars. They do. The deeper question is what kind of planets they are — and whether any of them can tell us something about life.

“I think the question about the planet is solved,” Queloz said in an interview during the 75th Lindau Nobel Laureate Meeting. “There are plenty of planets orbiting other stars, so there is no doubt about that. The question is really reflecting on the diversity and trying to understand how the Solar System fits in the picture.”

And eventually, he added, the question becomes life. “Ultimately, the question comes about life — whether we can say something about the potential of life on a planet, the likelihood of life, or even detecting life on a planet,” he added.

For a reader outside astronomy, this may sound almost simple. But a planet in a habitable zone is not a promise of a habitable world. Size, mass, atmosphere, the type of star, orbital stability, radiation, geological activity — all of these matter.

Planets as laboratories for life

Queloz now teaches and works at the intersection of physics, exoplanet research and the study of life in the universe. He also directs ETH Zurich’s Centre for Origin and Prevalence of Life — an interdisciplinary effort to understand how life can emerge and under what conditions it may exist beyond Earth.

Speaking at Lindau in a Synergy Talk titled “Why We Are Here, Why We Live, and Why We Die,” Queloz placed this question in a much longer history. The search for life beyond Earth, he said, is not new. What changed is the scientific capacity to approach it.

In the 1970s, Mars missions helped turn the old question into a practical programme. If a spacecraft went to Mars, scientists had to ask: how would we detect life? That question helped shape astrobiology, a field that tried to combine the astrophysical view of the universe with biology’s question of life.

The programme did not produce a dramatic discovery of life. But it changed the way scientists thought. It led to the study of extremophiles — organisms that survive in extreme environments on Earth — and showed how resilient life can be. Still, Queloz noted, extremophiles tell us more about the ecological limits of life than about its origin.

The field then shifted again. Exoplanets changed the scale of the problem. “When you look at the galaxy now, there are as many planets as there are stars,” Queloz said.

Most detected planets are very close to their stars. “You have to imagine the orbit of Mercury,” he said. “Ninety percent of the planets we have detected would fit within the Mercury orbit.”

That creates an uncomfortable scientific fact: the only planetary system where life is known to exist still looks somewhat unusual. Astronomers have found systems that resemble ours in certain ways, but not a clear twin of the Solar System.

This matters because planets are now seen as laboratories where life might appear. “The planet is seen as the lab for life to appear,” Queloz said. “And the good news is we have as many labs as we can think about, because there is a diversity of planets.”

The search, however, does not lead only outward to exoplanets. It also leads back into our own Solar System. Venus, for Queloz, is one of the most important examples of how much remains unknown. It has almost the same mass and size as Earth, yet it became a radically different world. “Venus has the same mass and the same size as the Earth. Well, it is pretty obvious it is a very different planet. We have no idea why,” he said.

Did Venus once have water and lose it? Or did it never have it? The answer matters not only for understanding Venus, but for understanding whether Earth-like conditions are common or rare.

This is why certainty is difficult. Telescopes can detect atmospheres. Chemistry can identify possible biosignatures. Statistics can suggest probabilities. But proof is harder.

“I mean, we have no idea what is underneath 20 centimeters under Mars. And we only know a tiny bit of Mars. Think about that. You send a lander on Earth, you land somewhere in the Sahara or the Atacama Desert, and you conclude this is a desert planet. Quite wrong, right? So you see. So I think it’s just the beginning” Queloz explained.

“A good scientist will never be fooled by any AI system”

The search for life beyond Earth needs this kind of discipline. Scientists must be open to strange signals, but also suspicious of them. A signal may be real, or it may be the result of the way it was measured. A pattern may reveal something, or it may show what researchers hoped to see.

This is where Queloz’s view of artificial intelligence becomes relevant. Modern astronomy works with vast amounts of data, complex models and increasingly automated systems. AI is already part of that world. But for Queloz, it is not a mystical threat to science. It is a tool.

“We are using AI, of course,” he told Mahabahu. “It’s a great tool. I think it’s a fantastic tool. We’re just discovering how to use it.”

He compares AI to earlier technological shifts: computers, telephones, airplanes. Each changed society. Each produced fear. Each needed time before people understood its uses and limits.

“There is no reason to get scared,” Queloz said. “AI is a change of society, like computers in the 1970s. It’s a massive change. We have to get used to it.” But tools do not remove the responsibility of the scientist. When asked about AI hallucinations and scientific errors, Queloz rejected the idea that science simply trusts its instruments.

“A scientist will never trust any equipment whatsoever, especially when it does something strange. Never ever,” he said. “A good scientist will always consider that the equipment can be wrong.”

For him, this is not specific to AI. It is part of the scientific method. If something unusual appears in the data, the response should not be excitement alone. There should be greater caution.

“If you want to see something, you will see it,” he noted. “But a good scientist will never be fooled by any AI system. Never. Because when you feel there is something unusual, an anomaly, you will be even more careful.”

This attitude matters in the search for life. The first claimed signs may be ambiguous. The most exciting signals may also be the most dangerous ones intellectually, because scientists and the public may want them to be true.

Queloz also does not believe AI will kill curiosity. “Not at all,” he said. “It’s like the phone. When we had the phone, did people stop meeting each other? No. When we had the computer, did people stop writing? No. It’s just a tool.”

Future of science

Machines can calculate, search for patterns and process routine work. But they cannot decide the central human question: what is worth asking?

That question requires freedom — not as an abstract ideal, but as a practical condition of science. Researchers need time, funding, institutions and space to pursue difficult questions.

The geography of science is also changing. Queloz noted that the United States became dominant in science after the Second World War because it invested heavily in research for decades. That history, he said, explains why so many Nobel laureates have been linked to American institutions. But he does not see this dominance as permanent.

“There will be more Chinese, more Indians, more Southeast Asian scientists,” he said, pointing to regions where investment, education and scientific capacity are growing. Africa, he added, has no shortage of talent, but the conditions for researchers living and working on the continent are often not yet sufficient for work at this level to flourish.

For countries outside the traditional Western centres of science, this matters. The next era of discovery will not be shaped only by who asks the oldest questions, but by who builds the institutions capable of pursuing them for decades.

At Lindau, Queloz also met young scientists, though he was modest about how much one can learn from brief conversations.

“They all have the energy and the youth,” he said. “They have this appetite for science. This is great. I keep telling them: do what you want. Some of them will be successful and some will be less, but it shows where the future goes. This is them, clearly.”

Queloz’s final worry is not whether humanity will eventually develop the technology to search deeper. He believes it will. “My only worry right now is: is our society going to survive long enough to develop the technology to make it happen?” he asked. “Because we will. But do we have the time? I’m not sure.”

Photos: The European Southern Observatory, Nobel Media, IAC

Olha Konsevych: Journalist, researcher; Vital Voices; GMF; WZB Berlin ;  Max Planck Society alumna ;Mahabahu Correspondent

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