Alien life on K2-18B? What do we really know: the astrophysicist Amedeo Balbi speaks

Have we really found proof of the existence of life outside the earth? After the news circulating in the media a few days of the discovery, thanks to the James Webb spatial telescope, the strongest alien life tests on a planet not of the sun system, 124 light years from the earth, we asked Amedeo Balbi, associate professor of astronomy and astrophysics at the Physics Department of the University of Rome Tor Vergata, how real this possibility is.

On K2-18b, an oceanic world to 124 light years from us have been detected composed that on earth are produced only and exclusively by living beings. Is it proof of the existence of extraterrestrials?
«We cannot yet talk about a definitive test. A compound called Dimetylsolfuro has been observed in the K2-18B atmosphere, which is produced mainly by marine organisms such as plankton on earth. A possible interpretation is therefore the presence of living organisms on that planet. However, there are many variables to consider: we do not even know with certainty if an ocean exists on K2-18b. The identification of the molecule must also be confirmed, and it is necessary to exclude that it has not been produced by non -biological chemical processes “.

So, could dimetylsolfuro also derive from non -biological processes?
«Yes, it is a possibility that should be carefully investigated, also through laboratory studies. On earth the dimetylsolfuro is mainly of biological origin, but in theoretical line it can also be formed by a non -biological way ».

Can we consider this discovery as a significant step in the search for extraterrestrial life?
«It is certainly a very interesting clue, perhaps the closest to a direct connection with biological activities compared to other data collected so far. However, it serves prudence: the verification process will be long and will proceed by small steps ».

In the future, will the search for life continue in this way, looking for chemical traces?
“Exactly. We cannot send probes on distant planets, so let’s analyze the stellar light that crosses their atmospheres thanks to the observations of the telescopes. When the light of a star passes through the atmosphere of a planet, it leaves footprints that indicate which molecules are present. The reason why this discovery was presented in such an empathic way is that, until today, no other molecules had been found with a direct connection with organic production. And therefore there is enthusiasm, perhaps even a little excessive ».

How should you proceed now?
«It is important to go one step at a time and progressively understand if we actually find ourselves in front of a biological activity. It is an interesting clue, which will have to be deepened, but we are still far from being able to talk about a certain test of life on an extrasolar planet. However, today we have tools that allow this type of investigation, which until a few years ago would have been unthinkable ».

And then?
«Further observations will be made with the same tool, the James Webb spatial telescope. The research group that made this announcement had already conducted similar studies a few years ago on the same planet: the novelty does not concern both data, as the level of confidence in the results. Even if there is greater trust in the presence of the dimetylsolfuro, we do not yet have a definitive certainty. Further research will be needed. In addition, other groups have proposed different interpretations: some, using the same data, hypothesize that K2-18b is actually a gaseous planet, not an ocean world. This shows how far we are still far from a definitive understanding ».

And the probabilistic studies that speak of numerous civilizations in our galaxy?
«A certain skepticism must be maintained. We know that there are many planets in our galaxy and that a fraction of these could have characteristics suitable for life as we know it. So if we say that it is likely that there are many worlds that could host life, this is a fairly correct statement and actually based on real data. When we begin to say: therefore it is likely that there is life, we do an inference there that, in my opinion, is not supported by what we know. We know a single case, that of the earth therefore we generally say behind these statements there is the idea that what happened on Earth must be typical, but this is a hypothesis, it is not something that we can be sure ».

So we don’t know if elsewhere exist thinking beings or complex life forms similar to us?
“Exact. All our considerations are based exclusively on what we know on our planet. We should find at least another example to clarify things ».

Are you optimistic about future prospects?
«What I know is that now we have many possibilities to scientifically solve things. The research is making great steps forward. We have telescopes such as James Webb and in the future we will have others even more sophisticated. Even if the final response may request one or two decades, we are proceeding in the right direction. We must study the atmospheric and climatic compositions of the planets, collect data and create interpretations. I don’t know if we will find life out there, but we are certainly approaching the possibility of understanding it ».

Is there the possibility to send probes to other planets?
«Within the sun system, yes: we will continue to explore Mars and the moons of Jupiter and Saturn, where they could, in theory, exist forms of microscopic life. But as regards planets outside the sun system, unfortunately not: the distances are enormous and current technologies do not allow us. For the next hundred years, I don’t think it will be possible ».

So we have to wait for the aliens to arrive with us?
“It is equally difficult for them too. The laws of physics are universal. Even if they were very advanced civilizations, they would have quite insurmountable barriers, due to the enormous distances and the impossibility of overcoming, or even just approaching, at the speed of light. It is complicated for everyone, if it were easy maybe they would have already arrived ».