The power of life

We know that life needs a planet to develop. How much of the “seed” must come from space is still an open question today. There are elements that seem to support the idea that life developed as a kind of chemical laboratory experiment on planet Earth, most likely on its surface. The whole principle of the chemistry of life is about energy. It is like cooking: you need a very high-energy starting point, because the more you transform your chemistry, the more energy you lose. If you want to create new chemicals, you need to find a way to add more energy into the system or to break energy barriers through what is called catalysis, in order to produce new elements.

Now, a series of reactions discovered in the last ten years suggests that the origin of life is a mixture of elements occurring at the surface of planet Earth, with some water, triggered by energy from the Sun — especially ultraviolet radiation, which, at that time early in the Solar System, was reaching the surface of the Earth.

Now, what is interesting today is that we only observe one kind of life on planet Earth. It is worth reminding ourselves that there is no fundamental difference in the structure of life between bacteria and us, or between the trees outside and us. We are made of the same components. We are built in the same way. We are simply the result of different branches of evolution. But at the origin, we all come from the same element, and it is the same chemical principle that governs life.

One of the surprising aspects of life on Earth is that we have evidence from the remnants of early life showing that it started very early in the history of the planet. The Solar System is about 4.5 billion years old, and we have evidence of life after about 1 billion years. If you go back 3.5 billion years, you find traces of life, usually preserved in rocks.

It then took a very long time for life to evolve. It remained at the bacterial level for a long period, without using oxygen, relying instead on other mechanisms to obtain energy — possibly a combination of factors such as heat from the Earth, volcanic activity, or radiation. The early atmosphere changed and evolved, and the Earth as we know it today is very different from the early Earth. Life itself produced oxygen, which was the major transformation of the atmosphere and enabled the development of more complex forms of life.

At some point, life began to move, marking the beginning of animals, which only appeared about half a billion years ago. This shows that the timescales involved are very significant. Understanding the origin of all these processes is at the core of the question of the origin of life.

A related question is how far these processes may have occurred on other planets. Asking about the remnants of life as we know it on Earth — on Mars and Venus — is therefore a very valid question. If we assume that similar conditions existed, we might expect similar processes to have taken place on those planets as well. If, in the coming years, we find evidence that similar forms of life once existed on these planets through the remnants we discover, it would be a fascinating result. It would suggest that there is a kind of universal process which, given the right conditions, leads automatically to the emergence of life.

We know Earth, and from Earth we can try to extrapolate. The rocky planets we currently know that are not extremely hot or cold are not truly Earth-like, in the sense that they orbit stars very different from the Sun. In most cases, these stars are small, known as M stars, and the planets orbit much closer to them. The difficulty in extrapolating from Earth comes from the fact that low-mass stars have very different characteristics. They produce different kinds of radiation, and the formation processes of their systems must also have been different, since these systems are not the same as the Solar System.

When addressing the question of life, staying close to Earth-like conditions makes it easier to identify life that we could recognise and test for. That is why we aim to find systems similar to our own. Unfortunately, Earth-like planets around Sun-like stars have not yet been detected.

We are going to do that. It is one of the main focuses of an experiment I am about to begin. It relies on a proven technique — detecting stellar motion through radial velocity — but with a crucial difference: we will observe a small number of stars very intensively. This has not been possible so far, because it requires a dedicated instrument and significant telescope time, and it takes considerable effort to convince the community to provide the necessary funding and telescope access.

In the future, we expect that Earth-like systems do exist. If we can demonstrate a method that works to find them, we will be able to map the neighbourhood of the Solar System — around a thousand Sun-like stars within 100 to 200 light-years. Given enough time, we should be able to determine which stars host systems similar to our own, or at least not too different from the Solar System. From there, we can begin to think about building a major observatory — perhaps on the Moon or in orbit — to start taking pictures.

The challenge, when asking questions about the diversity of life or how widespread life is in the universe, is how to find it. The minimum approach is to consider the basic conditions required for a planet to support life. One is that the planet must be rocky; it must have water; and it must have an atmosphere, whatever that atmosphere may be. Finding these three conditions does not guarantee life, but we understand them as the minimum requirements, because they were present on early Earth. We have not yet been able to identify such conditions elsewhere, but we hope that in the future we will be able to do so systematically.

There are also more extreme cases. The most definitive case would be to find a planet whose atmosphere is identical to that of Earth. In that situation, you would be compelled to conclude that life exists there, and that it likely performs similar functions, because it produces exactly the same atmosphere. But this is an extreme case. In reality, there is a wide spectrum of possibilities. Depending on the situation, you are dealing with probabilities. You might detect an atmosphere and say: this is a promising atmosphere, but there is no direct evidence of life. Yet there could still be abundant life that we simply cannot detect. If you had observed Earth during its first billion years, you would have had no indication of life. Still, you would have detected water, an atmosphere, and a rocky planet — enough to suggest that life might be possible.

Within the Solar System, the situation is easier, because we can bring back rocks. Imagine retrieving a rock from Mars, analysing it in the laboratory, and finding something moving — that would be a direct detection of life. It could be easy like this. Life might also reveal itself through strange chemistry. On Earth, we typically confirm life by cultivating it. Yet, perhaps surprisingly, we have no idea whether nearly half of what we cultivate is alive on planet Earth. Biologists refer to this as the “dark matter” of biology: they can detect DNA and all the signatures associated with life, but they are unable to cultivate these organisms to demonstrate growth and replication. By strict biological definition, something is not considered alive until it can be cultivated. This illustrates the immense complexity of the problem. It is likely that detecting life will remain a significant challenge.

In practice, there will be a growing body of evidence, and from this you can build increasingly long lists — each reflecting different preferences. Some people would insist on evidence of plate tectonics, for example, by detecting volcanic activity or outbursts on a planet, since plate tectonics is key and is what differentiates Earth from Venus.

Others would argue that a magnetic field is essential, and they are right. Mars, for instance, has lost its atmosphere largely because it lacks a magnetic field. A magnetic field is crucial to protect an atmosphere from being stripped away by the solar wind, and also to shield the surface from high-energy particles that are lethal to life. So you can construct a long list of necessary conditions before reaching a clear indication of life. There will always be some degree of uncertainty, and in the end it becomes a statistical assessment of likelihood. In some cases, you may have a high expectation that life is present; in others, a much lower one.

I still believe we might one day be fortunate enough to find a planet that is an exact analogue of Earth. That would suggest that the evolution of life follows a universal trajectory — that there is a kind of universal theory of life. It would imply that life always uses the same chemistry and develops similar components, because that is the only viable pathway. There may be no alternative that works.

The fundamental ingredients of chemistry are known. We are not going to discover new atoms. We expect life to be based on carbon and water, or perhaps another solvent, but elements such as nitrogen, carbon, and phosphorus will always be present, because they are ubiquitous. The complex chemistry, however, may vary — or it may be that there is only one viable pathway, the one we observe on Earth, which we will find everywhere. This question can be answered. As soon as we have observations of hundreds of planets, and as soon as we detect atmospheres, if life is everywhere and follows the same pattern, we will recognise it. That is my view.

If, however, life is rare or highly diverse, we may struggle to understand what we observe. There is still much to learn, and unfortunately I will not live long enough to see the outcome. Nevertheless, it is a fascinating prospect, and I hope it will motivate our species to stay alive. Because the greatest risk we face today is our own behaviour. Given the current state of the world, I am not confident we could sustain an experiment lasting more than a hundred years. Unless we fundamentally change how we operate and live together on this planet, we are bound to disappear — because we're just crazy as a species.

I think we are all philosophers to some extent, because we are alive and we all face the same fundamental challenges. We know that we are going to die. We know that our impact on this planet is very limited and short-lived. We know that we interact with other people, that we are sensitive beings, and that we respond to emotions. In that sense, we are all philosophers, because we all experience these conditions.

Some people may be more philosophical than others, because they are more aware of what they experience. I am aware of the chance to be alive. I am aware of the consciousness I possess, and I try to use it to contribute to the development of a broader, shared consciousness across our species. I am also aware of the need to interact with my peers in order to build continuity in knowledge and understanding, which I think is something exceptional in our species. It has never happened on Earth before. We are the first species to reach this level of consciousness — perhaps the only one in the galaxy, or even in the universe at this moment.

But there is a price that comes with this level of consciousness: the power to understand the universe. And once you understand it, you can replicate it. When you can replicate it, you gain access to immense power — the power of destruction, which we began to develop in the twentieth century, and potentially the power of creation. One day, we may be able to produce life in the laboratory. If we truly understand it, we should be able to do it. It is going to happen.

At the same time, we are already talking about artificial intelligence, and there may come a moment when we are able to create consciousness itself. These are tremendous powers — the powers of god. This inevitably leads to philosophical questions: if members of our species are developing such capabilities, are we able to control them? Will we use them for good? I have my doubts, because, fundamentally, we have not changed. We are the same as we were a million years ago.

We have built our success, I think, on curiosity, on the ability to work together, but also on a certain level of aggressiveness. If you look at the diversity within our species today, everything is present in our societies. We have people who are extremely benevolent, who want to help and cooperate. We have people who are deeply curious, who push the boundaries of knowledge as far as possible. But we also see the third part of this triangle: people who are highly aggressive, driven by power, and who can become a source of our own destruction.

It is this mixture that makes our species both fascinating and very dangerous. That is one aspect of my philosophical perspective. The other is that I am fully aware that I am going to die. In practical terms, I do not worry about it, because I feel there is so much to do on this planet, and so many emotions to share with others. I want to engage with as many people as possible and to understand my place in the world, and within the broader structure of the universe.

I do not think we have any particular role, except perhaps to be the only beings aware of the universe. And that’s hope! This will be enough to motivate our species to continue evolving — and to still be alive in a million years.

Editor’s note: The original filmed interview has been edited for length and approved by the author. This article has been transcribed from the original interview filmed with the author, lightly edited and carefully proofread. Edit date: 2026