Interview with Łukasz Wyrzykowski, Ph.D., from the Astronomical Observatory of the University of Warsaw, specialist in the field of searching for black holes.
– You are an astronomer and a musician. Do these two areas have anything in common? Ancient Greeks believed in the Music of the spheres.
– One thing that combines these two areas is maths and it allows astronomical phenomena to be presented in the form of sounds. Actually, people keep doing it all the time — even the latest observations of gravitational waves have been translated into music. I have also made some attempts to translate changes in the brightness of stars that I observe into music. But I am more an amateur musician, not a professional.
My brother, on the other hand, is a professional conductor. When we were kids, we were both interested in music and exact science. Then he followed the musical path and I focused on science — but music has always been present in my life. When I worked in Cambridge, I led a choir in the Polish parish. I also listen to music at work: usually Baroque music in the morning, and jazz in the afternoon. Just now, as I am preparing to give a lecture in the Planetarium, I am also wondering what music to choose.
– Music, exact science… It seems to me that you and your brother grew up in a very inspiring environment.
– We come from Choszczno, a small town near Szczecin. We owe our interest in music to our mother, and in science — to our fantastic high-school teachers. I also have a debt of gratitude to the Polish Children’s Fund, which organises various classes and workshops for kids and supports young talents. Now I am trying to repay this debt by leading my own classes for young people.
– And how are they doing? Do they have a mind for astronomy?
– Definitely! Some of them do expect romantic looking at the stars but the majority think in a very modern way and, what is very important, are good at programming.
– Yes. Today astronomy is mostly about writing correct algorithms. There is one more branch of science which depends on computers to such extent, and it’s genetics. Both astronomy and genetics have to analyse huge amounts of data.
– So you are a programmer?
– That’s maybe a bit of an exaggeration. When I worked in Cambridge, I cooperated with real programmers — and I still do. These are people who are able to change a code that would take years to calculate something into a different code which does all the calculation in just a couple of minutes. On the other hand, they don’t have any knowledge of astronomy and physics. I have it and I am quite good at programming, and that’s why we complement each other and our cooperation runs smoothly.
– How does a black hole seeking algorithm look like? Because this is what you deal with, am I right?
– Everything is based on spotting changes in the level of star brightness. The first method is called gravitational lensing and bases on the same phenomena that allows us to discover extrasolar planets. If a black hole or a planet keeps moving in front of a star, for some time it will strengthen the star’s light – we know that from Einstein’s theory of general relativity. Now, the whole trick is to be able to say if the lens is a plane or a black hole.
– And the second method?
– The second method allows for detecting bigger black holes. It also consists in searching for flashes — but longer ones that last up to a few years. Such flash may be a sign that a black hole is just swallowing a star.
– How many black holes have you found using these methods?
– I have three candidates but I still need to verify them.
– Three? It doesn’t seem a lot.
– It depends how you look at it. Please remember that so far in our galaxy — this is my field of interest — only 20 black holes have been found.
– Only twenty? So why is there so much noise about them? All those books, films, songs? I even remember worrying as a child that I might fall into a black hole after I read a sci-fi story.
– Black holes are very inspiring, they stimulate imagination of both artists and scientists. However, it has to be stated clearly that all hypotheses calming that our physics doesn’t work there or that they are passages to different universes are just pure fantasy — even if written with the language of maths. We don’t know what is inside black holes. And the way I see my task here is that if we manage to find more black holes — which is exactly what I am trying to do — we will have the possibility to find out more about them. Not hypothetical and imagined black holes but the concrete ones.
– How many black holes could there be in our Galaxy?
– My friend theoretician, with whom I talk about it quite often, says there could be about 3,000 of them.
– How do you calculate that?
– A typical black hole, which weights as much as a couple or a couple of dozens of Suns, is formed after a stellar explosion called Supernova. No every Supernova, though — only if the exploding star is really massive. We are able to calculate the number of explosions of stars that had been huge enough to leave black holes as a result.
– But there are also larger black holes, as big as a million Suns. Just like the one in the centre of the Milky Way.
– Yes and they are very mysterious. Probably there is one such giant in the centre of every galaxy, although it’s not 100% certain. We also don’t really know where they came from. They might have been formed as a result of unification of smaller black holes during the clash of galaxies. But even then it’s hard to explain their massive weight. So maybe they had formed into black holes right from the start? We really know very little about these objects.
– Will we ever find out more about them? How can we explore an object that doesn’t even transmit light?
– I think we will. Today we have tools and scientific methods we couldn’t even dream of in the past. We are, for instance, starting to register gravitational waves, which for astronomers is as important as the invention of the X-ray was for doctors. It opens a whole lot of new possibilities. Who knows what we will come up with in the future? It’s also important that astronomy is a field of science that interests people — because space is fascinating. The society wants us to conduct our research, even if it doesn’t have immediate or practical results. Every time I am at a party and I mention that I am an astronomer I am bombarded with all sort of questions straight away.
– Are you happy to answer them?
– Of course! I sometimes think that temperament is what differs us from physicists. It would actually be quite hard to find an astronomer, who is an extreme introvert immersed in his theories. We, astronomers, are physicists whose laboratory is the night. We have to go outside and look up to the sky. This opens us to the world.
Interview by Łukasz Kaniewski.
Date of publication: 27 April 2016
Łukasz Wyrzykowski, Ph.D., assistant professor in the Astronomical Observatory of the University of Warsaw. His fascination with astronomy evolved in high school, where he was a member of the Almukantarat club and as a scholar of the Polish Children’s Fund. He studied and wrote his MSc and PhD in Warsaw but also spent nine years in science centres of Tel-Aviv, Manchester and Cambridge University. In 2000, he joined the Polish OGLE project, which has discovered extrasolar stars, thousands of variable stars and quasars. Since 2008 he has been involved in the Gaia space mission, where he is responsible for the search of Supernova explosions and other temporary phenomena. For the last few years he has conducted research on the dark matter. His discoveries proved that dark matter is not found in large quantities in compact objects. Currently, he is looking for black holes by combining the opportunities provided by the on-land OGLE project and cosmic Gaia mission.