August 5, 2020

"The exploration of life on other planets will be the task of astronomy of the next century" | Science



The International Astronomical Union (UAI) celebrates its centenary this year, and the Dutch astrophysicist, Ewine van Dishoeck, its new president, has set itself the task of bringing the science that studies the stars, their movements and laws, to the public. Also to encourage more women, who now make up 18% of its members, to become astronomers. He has only five months in office, already marked by the arrival to the hidden face of the Moon of the Chang'e-4 probe, launched by the Chinese space agency, CNSA, and the first photos of Ultima Thule, a binary object located at 6,600 million kilometers from our planet, captured by New Horizons, the NASA probe. Two great events that not only underline the Chinese presence among the great powers of the new space race that is approaching. Above all, they mark the challenges of the future. From a closer observation of black holes, and the possibility of mounting a lunar space station as a springboard to travel to Mars, to the search for life on other planets: the great cosmic adventure.

This Sunday, Van Dishoeck, born in the Dutch town of Leiden 63 years ago, was sitting next to one of the telescopes at the Leiden Observatory, the Dutch city where she is a professor of Molecular Astrophysics. During the weekend, similar centers around the world have organized some 750 visits and colloquia in 87 countries to commemorate the UAI century of life. The rest of the year, there will be more activities around the theme "Under the same sky", to show how our vision and knowledge of the cosmos has changed.

Question. How has astronomy evolved since 1919, the year of the foundation of the UAI?

Answer. One hundred years ago, we ignored things that we take for granted today: how the stars shine, the size or structure of the Universe, or the existence of other planets around stars like our Sun. We have gained in knowledge and technology, and this has had repercussions in society and science in general. In 1995 we found the first extrasolar planet, or exoplanet [bautizado 51 Pegasi b, porque orbita la estrella 51 Pegasi, en la constelación de Pegaso, lo detectaron los astrónomos suizos Michel Mayor y Didier Queloz]. Today we know that there are about 4,000 of these planets, and that each star has at least one in its orbit. We know where to look, so the next challenge is to determine the composition of your atmospheres and look for signs of possible life there. That exploration on other planets will be the task of astronomy in the next century.

P. It has been speculated for centuries about the possibility of life out there. Has the time finally come to find out?

"What we hope has nothing to do with the green people of popular culture, I think of much simpler forms of life, or maybe something more complex: that they have already developed artificial intelligence in the form of robots.

R. We are the first generation of human beings with enough technology to approach this question from the scientific point of view. Astronomers, and people in general, have made many conjectures about the existence of life in the Universe, and toward that search the large installations under construction are oriented. For example, the Extremely Large Telescope (ELT), in the Atacama desert in Chile, which will be 39 meters in diameter. Proposed by the European Southern Observatory (ESO, also in English), it will allow us to measure the light spectrum of exoplanets to deduce their characteristics and look for signs of life.

P. What do you expect to find?

R. We are talking about molecules, other species, or a combination of species that can signal the presence of life on other planets. Unicellular bacterial life, which is what first appeared on Earth after its formation, although it took millions of years. The multicellular cost billions of years. Of course, nothing to do with the green martians of popular culture. I think of much simpler life forms, or maybe something more complex: that they have already developed artificial intelligence in the form of robots. We do not know.

P. China has reached the hidden side of the Moon and revolutionized astronomy. Maybe a new space race will open. Why is it so important to have landed there, apart from the national pride of being first?

R. The year 2019 has started big with the Chinese exploration mission Chang'e 4. We know little about the non-visible part of the Moon. For example, we have never studied its composition, which seems to be different from the one we do see, from the point of view of craters or their stones. I do not know the details, but it is interesting to investigate, and from the International Astronomical Union we congratulate China. It is good that they develop their space program. They also have theirs United States, Europe, with the European Space Agency (ESA) or Japan. By the way, this year also commemorates the 50 years of humanity's arrival on the Moon (the Apollo 11, in 1969).

P. Does it seem feasible to build a space station in the Moon's orbit to facilitate a possible trip to Mars?

R. It is a project in consideration. In mars, we investigate its history and the existence of water, and therefore, of life. It may have, like Venus, the same amount of water as Earth. But while the second planet is too close to the Sun, and being too hot, lost it, Mars is small compared to us. He could not contain his atmosphere and his water, so he evaporated. Mars is important not only for being the first to arrive.

P. Black holes are even more popular than Mars. To what do you attribute it?

R. They have always been a stimulating phenomenon. They had known each other for a long time, but we have more data. We know that there is a super large one at the center of our galaxy. We have seen it thanks to the movements of the stars around it. And also for other energetic phenomena. They are important to study the formation of a galaxy. There are black holes supermassive, with millions of times the mass of the Sun, and other stellar, arising from the death or collapse of massive stars. And the good thing is that we can study the fusion of some of them through the gravitational waves [perturbaciones en el espacio-tiempo producidas por materia acelerada, transmitidas a la velocidad de la luz] that allow us to open new eyes towards the Universe. NASA and ESA collaborate here.

"In the Astronomical Union we have created a working group to see how we can attract more women, because only 18% of our members are"

P. You studied Chemistry, then went to Astronomy and have received awards in Europe and the United States. Do you miss a greater presence of women astronomers?

R. In the Astronomical Union we have created a working group to see how we can attract more women, because only 18% of our members are. It is true that to join you have to be advanced in the race, and that in the junior category there are more women. In the University, they are between 30 and 40% of the students. There are countries, such as Brazil and Argentina, where there are many astronomers. In southern Europe there is usually more than in the north, and I have heard all kinds of explanations. Including the tradition, earlier greater, of course, of the segregated schools where the girls seem to have less pressure from the group -with boys- when it comes to studying science. The important thing is that they come, and by the end of 2019 we hope to organize a symposium in Japan on inclusion and diversity in astronomy.

P. And science fiction movies. Is it pure fantasy?

R. There are movies, like Gravity (2013) and Interstellar (2014), which approach the laws of physics. Others, like the franchise of Star Trek, that I love, they take great liberties. That of the warp speed, a theoretical form of propulsion at speeds much higher than that of light, is far from being achieved.

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