Space exploration will soon experience a big boom, says the new holder of the “Austrian Nobel Prize”

Slovak astrophysicist Norbert Werner had an extraordinary week in the second half of March 2021. On Monday, he watched the launch of the Soyuz rocket carrying the first nanosatellite for detection of gamma-ray bursts into orbit, on which he participated in the development. Just four days later, he received the Ignaz L. Lieben Award, also known as the ‘Austrian Nobel Prize’.

Which of the two exceptional recent events has made you happier?

Without a doubt, receiving the Ignaz L. Lieben Prize awarded by the Austrian Academy of Sciences made me extremely happy, with no “buts”. While the launch of the satellite also made me happy, there are many “buts”, such as whether everything will work, can operate the satellite as expected and if we can really meet all the goals we have set. There is still a lot of work to do; we are just at the beginning.

What are the goals?

We first want to verify the detector actually operates correctly. The instrument is designed to detect and monitor gamma-ray bursts, which occur during collisions between neutron stars or during the gravitational collapse of very massive, rapidly rotating stars.

Why are gamma-ray bursts important for astrophysicists?

They are scientifically interesting for several reasons. For example, they can help clarify the origin of the elements. We know that after the ‘Big Bang’ there was only hydrogen and helium in the universe. Thanks to a unique observation in 2017, when both gravitational waves and a gamma-ray burst from a neutron star collision were detected and located at the same time, it was found that neutron star collisions produce elements heavier than iron, such as gold or platinum. Observing these phenomena can be very helpful in clarifying the evolution of the universe.

Has there been such an observation since then?

No. Currently, there is no device that would be able to monitor the entire sky and, at the same time, locate the source of the flash. Furthermore, any such observations would need to be continuous and routine. Thus, the idea gradually arose to use detection devices placed on a system of nanosatellites for monitoring gamma-ray bursts. We would like to send a whole fleet of nanosatellites into space so that the measurements cover the entire sky. By linking the data obtained, we would be able to locate where the gamma-ray burst came from and make further measurements and observations.

How did the idea to use nanosatellites come about?

After the crash of the Japanese X-ray astronomical satellite Hitomi, on which I worked for several years, András Pál from the Hungarian Astronomical Institute and I began to think about how the so-called nanosatellites could be used. Their construction is not so demanding and they can be built quite cheaply. We came up with the idea of watching gamma-ray bursts. However, I’m not an expert on gamma-ray bursts, and nanosatellites are not what I focus on. It just seemed like too good an idea not to try. We then invited experts dedicated to these subjects onto the team.

So, what do you do?

My topic is X-ray spectroscopy and I focus on high energy astrophysics, in which we study those sites in the universe that are the hottest and have the most energy. This mainly refers to intergalactic gas in galaxy clusters. Only about ten percent of the normal mass of the universe is in stars and planets, the rest being this gas, which heats up to emit X-rays when it hits the gravitational field of galaxy clusters. It is this radiation that we focus on when examining the properties of intergalactic gas. We also examine the behaviour of black holes in the centres of galaxies, which also interact with the gas and play an important role in the evolution of galaxies.

The Austrian Academy of Sciences praised you for your contribution to X-ray spectroscopy. What does this prize mean to you?

I am not a prize collector, but I must admit that I am really proud of this award. At first, when they told me, I felt I still had to earn it.

But you already deserve such prizes for your research into intergalactic gas and black holes. What does this entail?

The intergalactic gas that surrounds the most massive galaxies cools and should form stars. However, there are supermassive black holes that create a huge amount of energy when absorbing the surrounding matter, which is then released either in the form of light, in the case of so-called quasars, or in the form of jets, which then heat the surrounding gas again. In fact, black holes prevent the cooling of intergalactic gas and thereby promote star formation in the largest galaxies in the universe. This is one of the research directions that we are focusing on now.

Where do you see this research going?

We would like to focus on galaxies such as our Milky Way, in order to verify whether what we have discovered in the most massive objects in the universe, which are clusters of galaxies, also affects the evolution of individual galaxies. In other words, how hot atmospheres and black holes affect the evolution of galaxies like ours. This is a completely unexplored area. Another topic is the so-called ‘fibres’ of the cosmic web, which connect clusters of galaxies. They are difficult to detect because they are very dim.

So how do you do it?

When I was twenty-five, I had this idea that we should aim a telescope between two clusters of galaxies so that we wouldn’t look at the ‘fibre’ we expected to connect them vertically but longitudinally, which should allow us to observe everything better. It seemed to work out and we were given observation time, during which we discovered a ‘cobweb’ and hot gas exactly where the simulations had predicted. This was a really great discovery. Later on we discovered a fibre of dark matter, which, while we don’t know what it is made of, we can map because it acts by gravity on surrounding matter and light rays, which it then curves.

Will the Ignaz L. Lieben Award you received help your research in any way?

High energy astrophysics and X-ray astronomy are highly developed in the United States and Western Europe, but less so in Central Europe. Being awarded this prize could change that.

How did you find your way into astrophysics?

As a kid, I was fascinated by the universe. Even in my native Rožňava, while observing the stars in the sky, I imagined them spreading to infinity. At that time, there was minimal light pollution and we could see the Milky Way from our housing estate. Later, in a Carl Sagan Cosmos documentary, I first heard that stars are grouped into galaxies and that galaxies are not evenly distributed but form a kind of cobwebby structure. By the sixth grade of elementary school, I told myself that this was what I wanted to do.

Has your interest not changed for a moment since sixth grade?

At Pavel Jozef Šafárik University in Košice, I focused on asteroids and comets. I wanted to study things much closer to home and stay in our solar system. However, when I applied for a Doctorate with the University of Utrecht and the Dutch Institute for Space Research, I was offered the opportunity to pursue the space web, the very subject that has fascinated me so much since I was a child.

You spent twelve years abroad, eight of them at Stanford University. How did you end up in Brno?

I went abroad saying that I would like to return to my home region and start developing a new research direction, which I am now doing quite well. I had a great opportunity. Brno is an astronomical centre, and when I was at high school I devoured everything they did at the Brno Observatory. So, I like the city, and what’s more it’s close to Rožňava where I have my family, so it all fits nicely.

Do you think that astrophysics in general awaits development?

We have a very interesting decade ahead of us, with humans returning to the moon. Cosmonautics and all space research will experience a big boom. I hope that, as a result, young people will become more interested in engineering and science, because it will become ‘sexier’.

Will expectations of human settlement off the planet increase with the growing interest in the universe?

Humanity is returning to the Moon for knowledge. This was agreed by all the space agencies, which have decided to cooperate on a return to the Moon by 2028. Efforts are also being made for humans to fly to Mars; again, purely for the sake of knowledge - not to set up a second alternative to Earth there. I'm really sceptical about that though, and for two reasons. If there was any life on Mars, and I don’t know that there is, it wouldn’t be ethical to go there and contaminate it with our presence. It could destroy it and, at the same time, it could be dangerous for us. In addition, Mars is not a planet that would be extra pleasant to live in. I think we should focus on protecting our own planet Earth. We mustn’t destroy our own planet; that must be our priority, not to establish a city on Mars.

Thank you for the interview.
Tereza Fojtová

Translated by Kevin F. Roche