Manel Perucho: ’Science makes better societies, it makes us more respectful, more open and more aware of reality’

Manel Perucho holds a PhD in Physics from the University of Valencia (UV) and full professor in the Department of Astronomy and Astrophysics, and is a member of the Astronomical Observatory. His research focuses on active galaxies and relativistic plasmas, their role in the evolution of galaxies and the impact they generate on their environment. From December 16, 2022, he is also director of the Language and Linguistic Policy Service of the UV. He also collaborates in the -Stimulating scientific vocations- initiative of the Scientific Culture and Innovation Unit through his participation in conferences aimed at spreading scientific culture.

How did you become interested in the study of space?

I had an uncle who really liked to read about space and the Theory of Relativity, and he would explain things to me, like the Twin Paradox, which says that if a person travels at a speed close to the speed of light to the centre of the galaxy and back, for him it would not take as much time as for us on Earth. I became interested in it thanks to him and the summer skies. I wanted to know what was happening, why the stars were shining, what physical processes feed them and a little the why of it all, which is what every scientist wonders, what are we doing here and what is the meaning, which you don't end up finding never, but in the end that is the question, look up and look for answers.

What research have you been working on lately?

Currently, we have developed a numerical code to study the evolution of plasmas that have fundamental relevance in many astrophysical scenarios. Whenever there is an object on which matter falls, supersonic plasma jets are formed, which generate shock waves, heat their environment and condition it, it happens above all in active galaxies, which are the scenarios we study the most. We are investigating the evolution of these jets through our codes and how they relate to the galactic environment. We also try to improve the codes so that our numerical simulations are closer to reality and we can draw more conclusions.

On the other hand, we participate in the analysis and interpretation of observations and we hope to be able to publish shortly an article about some observations we made, where we used a device of radio telescopes spread all over the Earth, plus one that is in orbit. What we have done is analyse the results and we have been able to extract very relevant information about the nature of quasars, a type of active galaxy. I would say that the interpretation of these observations is one of the most relevant results we have obtained.

How would you define black holes?

A black hole is a rupture in the space-time fabric. In colloquial terms, space-time has a certain consistency, and the theory of general relativity interprets that gravity is caused by a deformation of this space-time fabric. If you take a sheet and put a stone it deforms, now you take a ball and throw it and it will roll until it falls, the fall is caused by the ball rubbing against the fabric. In the case of gravity, the absence of such intense friction keeps objects in stable orbits. The moment you put a needle head with the mass of twenty elephants in a sheet it holes, that is a black hole. What a black hole does is generate a very strong gravitational pull and we don’t know what’s inside. We know there is an event horizon and beyond that point we get no more information and we don’t know if the break leads somewhere else, if it’s a singularity, or if our interpretations have limitations and no such break occurs.

"The moment you put a needle head with the mass of twenty elephants in a sheet it holes, that is a black hole"

"There are different types of black holes such as stellar mass black holes, which are formed by the collapse of high mass stars, they can also be formed through a supernova or a direct implosion"

How are they formed?

There are different types of black holes such as stellar mass black holes, which are formed by the collapse of high mass stars, they can also be formed through a supernova or a direct implosion. The moment a star’s core runs out of fuel, what happens is that everything starts to collapse. If the star has a small mass, a compact object is generated, or if it is larger, a supernova explosion or outright implosion can occur, and as a result the core of the star collapses in on itself, because it has too much mass to resist collapse, and that’s when the black hole forms. We do not know the origin of the supermassive black holes at the centre of galaxies, but they were probably formed by the direct collapse of very large gas masses early in the evolution of the universe.

What are the jets associated with black holes?

When the black hole is accreting matter, that is, when there is a contribution of gas by different processes, such as the coalescence of galaxies, which occurs when one galaxy approaches another and by tidal forces, the gas one of them ends up feeding the black hole of the other, an enormous energy process takes place, the most efficient in the universe. What happens is that there is a magnetic field that is anchored to the gas that is falling and once it reaches the black hole it is attached to it. At this point, we must understand the magnetic field as a force that generates field lines. These lines are like hairs that offer a small resistance to the rotation of the black hole, which generates an extraction of energy that ends up producing the jet. This process can occur both in supermassive black holes in active galaxies and in binary stars in our own galaxy or stars in formation.

Could they pose a real danger to our galaxy?

This phenomenon can pose a risk to us in a specific case. When a star is collapsing, when the black hole is being formed, an ejection of energy occurs, which is called a gamma ray burst. This could indeed put at risk the atmosphere and, therefore, the life of our planet or any other that passes through it. The fact that the Earth is located on the outskirts of our galaxy is in our favour, it is cause and effect, we are here for that, in the centre of the galaxies there is a lot of activity and many explosions, it is dangerous to live there and, therefore, it is unlikely to find life in the centre of galaxies. The black hole itself is not dangerous; if you don’t go looking for it, it won’t come.

What are active galaxies?

They are those galaxies that have a supermassive black hole at the centre, which is being fuelled by matter. This process, which is very energy efficient, makes the galactic core shine as much or more than the entire galaxy itself. At first, the researchers thought they were stars, because they could only see the core of the galaxies, due to the light they emitted, and could not see their structure. Our galaxy also has a black hole at its centre, but it is not being fuelled by sufficient amounts of gas to create all that energy. A black hole in an active galaxy swallows one or several solar masses per year.

"The a ctive galaxies are those galaxies that have a supermassive black hole at the centre, which is being fuelled by matter"

"A black hole in an active galaxy swallows one or several solar masses per year "

"Surely at some point we will find some kind of bacterial being on some satellite of our galaxy or on Mars itself"

Do you think that future astronomical research will be able to prove the existence of life in our solar system?

NASA sent a probe to Titan, a moon of Saturn, to explore its surface, and they detected lakes where there could be molecules that could give rise to this organic chemistry, but there is no obvious proof. Then, on Europa, a moon of Jupiter, there is an ice core, but it is assumed that because of the heat that the core of the satellite can produce, there may also be a layer of liquid water where it could find -some type of organism, and it could also be found in the subsoil of Mars. It is a complicated matter, you need to bring samples to analyse them, and there are many technical complications to do so. The probes on Mars have done experiments from there, but the situation on Jupiter and Saturn is even greener. Surely at some point we will find some kind of bacterial being on some satellite of our galaxy or on Mars itself. We all agree that microbial life must be there, the difficulty is in the step towards consciousness, that is not so obvious.

Is there any possibility to exceed the speed of light or is it physically impossible?

Theoretically, there are particles called tachyons that propagate faster than light, but it is only on a theoretical scale. I would say that exceeding the speed of light is an unattainable limit. The only way to get close to the speed of light would be by investing huge amounts of energy or traveling through space using other methods that would be equivalent to traveling faster than the speed of light, but if we are thinking of taking a ship and accelerating it to exceed this speed would be impossible, it is an insurmountable physical barrier.

Space research requires large investments, should these studies be prioritised over others that may have a more practical application on Earth?

I wouldn’t frame the debate in those terms. Research must be funded, and better than what is being done, not only in the amount but also in the way. All societies have priorities, health research is obviously a priority and that is why it receives more resources than astrophysics. If what we do is fund only the big groups or only a few groups, we are doing it wrong because these groups may be doing very interesting things, but that does not mean that there is funding for other smaller groups, which maybe they’re doing things that don’t have direct application now. Science has never worked according to fads, and now it seems to work like this, research is being funded because it is now fashionable to study this. We are creating oases and a desert around the oases. It is necessary to study in all possible areas, because you never know where the next great discovery will come from and if we focus on fashions, we will generate knowledge gaps in other areas. In astrophysics, we need funding for telescopes and computers, but it is also necessary to train more scientists and take them out of precariousness.

How do you rate the University of Valencia’s initiative ’Stimulating Scientific Vocations’

The universities in Valencia must be a point of reference, and a society that does not have a powerful scientific body is a society that will necessarily lag behind. Science makes better societies, makes us more respectful, more open and more aware of reality. I doubt a lot of the things I think and this is thanks to scientific thinking, I don’t think I’m right in everything I say, but I am clear that in the recognition of rights we must move forward and not back down. In other matters it is necessary to doubt, great certainties are bad for the whole world and science also teaches you this. I think that promoting young people'’s interest in science cannot be to the detriment of anyone. We are in a country where having culture is restricted to the humanities and this is a historical mistake, we must have scientific culture and, therefore, this initiative is very positive.

" We are in a country where having culture is restricted to the humanities and this is a historical mistake, we must have scientific culture and, therefore, this initiative is very positive"

"What needs to be achieved is that if a woman wants to be a physicist, she doesn’t back down because she thinks it’s something for men, which is what happened before"

What do you think about the use of social networks and platforms like YouTube as channels for scientific dissemination?

Any platform is useful. Each spreader may like one thing more. Video production is more expensive, but also more impactful. There are people who disseminate on Twitter or Instagram and others, in writing. I like it better in writing, but either is good. What must be done is to be rigorous. When disseminating, sometimes you have to lower the level of discourse and speak in colloquial terms, but when you do, you must try to lose as little rigor as possible so as not to say things that are not true.

How do you rate the interest of women in the field of physics and astronomy?

We have a low percentage of women in the Physics degree. What needs to be achieved is that if a woman wants to be a physicist, she doesn’t back down because she thinks it’s something for men, which is what happened before, the enemy is cutting vocations because of a gender issue. Obviously, it is good that there are more women, unfortunately in my department there is only one female permanent teacher and we are very happy to have her, but we would like to see more. The problem with the Physics degree is that after the degree study it is so long that some women have to abandon it in order to lead a more or less normal life. Female scientists who have a partner and reach the age of 35 without a permanent position are forced to make a decision and it is not good that they have to make it. In order to contribute to the scientific career of women, there should be more references and the problem is that they do not get to be so because many times they are forced to make this decision. All scientists have gone through careers that are precarious enough to not forget them until we stabilise, in the case of women it is even more difficult and this must be avoided. The more references there are, it may be that more girls who had not considered it will consider it.

" The quality of teaching in Valencian and English must be equated to that of other languages "

What direction does the Language Service and Linguistic Policy intend to take in this new stage?

First of all, I will maintain the plan to increase teaching in Valencian that was initiated by director Rafa Castelló and which has been successful. On the other hand, we would like to incorporate master’s degrees into language policy, not only because of the increase in teaching in Valencian, but also because of English. It doesn’t make much sense that 90% of the Master’s degrees at the University of Valencia are in Spanish, the university’s academic point of reference must be Europe and, therefore, we need to deepen teaching in English. And with regard to professional master’s degrees, we must respond to a need to have psychologists, lawyers and teachers who speak Valencian. The quality of teaching in Valencian and English must be equated to that of other languages.

What can this service bring to the university and to our language in general?

The Language and Linguistic Policy Service is restricted to the university, but obviously the University of Valencia has a large social projection. To begin with, we try to dignify and give visibility to the fact that studying in Valencian is as possible as doing it in Portuguese, Italian or Danish, and that knowing more languages is something that favours you, because it helps you understand better other people and it is a step to study the grammar of other languages, it only has positive aspects. The same thing happens with English, it opens the doors to the academic and working world, it is the universal language at the moment. The university must train people, good citizens and this goes perfectly with learning languages and learning in languages.

"We try to dignify and give visibility to the fact that studying in Valencian is as possible as doing it in Portuguese, Italian or Danish"

"In a territory where there are two co-official languages, citizens have the right to be served by the administration in either of them"

What do you think about the need to have a language certificate in Valencian to access some public positions?

It is a question of user rights, in a territory where there are two co-official languages, citizens have the right to be served by the administration in either of them. This right is not respected in one of the cases and, therefore, requiring the civil servant to be able to respond to this right is an obvious thing. In Finland there is a Swedish-speaking community that represents 5% of the population and any Finnish civil servant has the obligation to learn Swedish in order to attend to the linguistic rights of this population. Here we are not asking to speak a language that is impossible to learn for someone who already knows a Romance language. An obvious thing is being asked, which is based on respecting people’s rights, it is not normal to go to the doctor and not be able to attend to you in the language in which you find it normal to express yourself.