Prof. Sośnica: – Copernicus changed our perspective on the universe

Why was the man who stopped the Sun and moved the Earth a great scientist? 

– He was an astronomer, an economist – to use modern terms, a doctor, a cartographer, a theologian... A true Renaissance man. His phenomenon lies in the fact that he changed the perspective on the world and the universe. Copernicus, who put the Sun at the centre, forced us to look at the bigger picture and to discover that man isn’t in the centre of the universe, but rather is on the sidelines.

The refutation of Ptolemaic astronomy, according to which the celestial bodies, including the Sun, revolve around the Earth, was not only a scientifically revolutionary concept, but also a kind of critique of the anthropocentric vision promoted by the Church at the time. And he was not afraid.

He was not afraid, but he also published his fundamental works quite late, and some of them were published after his death. So it can be said that in a sense he protected himself from trial or accusations of heresy. From the Catholic Church’s point of view his thesis was indeed revolutionary. Today we are able to look at the universe in a completely different way. Nicolaus Copernicus, however, did not have the tools that we have.

What instruments did he use for his research and analysis?

He didn’t have a telescope because in his time no one had yet constructed such an instrument. He had an astrolabe, a parallactic triangle, i.e. planks positioned in a way that allowed angular observations of celestial bodies. He had simple instruments at his disposal, some of which he constructed himself. He observed, drew and was not able to explain physically why celestial bodies move the way they do, as he didn’t know that gravitational forces were behind their movement. Instead, he was able to describe motion mathematically using the principles of geometry. Nicolaus Copernicus imagined such celestial spheres, i.e. the tracks along which the planets move around the Sun. On top of that, he was an idealist, so he didn’t know that these orbits didn’t  have to be exactly circles, but could be, for example, ellipses.

A total of 250 missions to the Moon are planned over a period of 10 years.

What did Copernicus see in his observations? Was "his" sky different or the same as the one we see today?

He observed what we observe today with the naked eye. And he saw above all the angular changes of the planets, the Moon, the Sun. So he was able to measure the angles at which the celestial bodies are at a given time.

And this was the starting point for the statement that the Earth revolves around the Sun, which is at the centre of our solar system?

If we put the Earth at the centre of the universe, we observe a very strange movement of some of the planets from the point of view of an observer on Earth. Sometimes they move in a given direction, then start to slow down, move in the opposite direction for a while, and end up forming loops. But when Nicolaus Copernicus put the Sun at the centre of the universe, it turned out that all the planets move in beautiful circles, in perfect geometrical figures, and on top of that the Moon moves in a circle around the Earth.

Did Copernicus look for beauty in the universe?

Yes, beautiful geometrical figures and a simple solution. And this solution turned out to be the alignment of everything with respect to the Sun, not the Earth.

What is beautiful about science?

The fact that you can discover new things and you don't really know what or how much is yet to be discovered. Breakthroughs like the Copernican one are also beautiful. I think the next one will be the possibility of human habitation on a celestial body other than the Earth. Until now, living organisms, and therefore man, have lived on a single planet. When we manage to build a permanent base and inhabit other celestial bodies such as the Moon, we will make a technological leap, but also a biological one, because life must be maintained on these space bases. It's not easy, because it's the conditions we have on Earth that are conducive to the development of life. And this life is very fragile. You only have to go high in the mountains above 5,000 metres above sea level to see that. In the Himalayas at this altitude, you don’t see any moss for example, yet the conditions there are not as extreme as on other celestial bodies.

Your team is involved in preparing a lunar mission.

A base on the Moon will be built by NASA together with the Canadian Space Agency and the European Space Agency. Our contribution to this endeavour is the satellite system we have designed, which will allow positioning on the lunar surface and communication. Astronauts living on the Moon will want to be able to access the Internet and talk to their families in real time. Our project is also important for controlling equipment such as lunar rovers and this control from Earth. Positioning is also needed to know where to land, as well as for rocket launches towards Earth and Mars. For the European Space Agency, we designed the components of the system, in particular the structure of the signal that will be transmitted by the artificial lunar satellites. In order to design the orbits of these satellites, we also studied what happens to satellites orbiting the Moon.

Meaning?

Our orbit will be quite unusual. GPS or Galileo satellites usually have circular orbits. Our satellites for the Moon will follow elliptical orbits. As a result, they will fly very quickly over the North Pole, and most of the time they will be over the South Pole, in order to ensure communication and positioning precisely over the South Pole - over which the base will be built. Our orbit was therefore designed for a specific purpose.

Are you afraid?

A little, yes, but in the case of the European Space Agency, we have created not only a master plan for the technological solution that we think is the most optimal, but also a backup plan. The agency can choose whether it wants a solution similar to the one that already exists, which is similar to the one used for GPS and Galileo, that is based on Kepler parameters with corrections, or a new one that achieves slightly higher accuracies but is based on a slightly different mathematical apparatus – Chebyshev polynomials.

The key issue of space mission design concerns risk and cost. There is also the problem of the mass of such a satellite. We could not, for example, use the accurate atomic clocks that are on board Galileo satellites, because the mass of these lunar orbiters has to be 10 times lower than that of Earth-based navigation satellites. Besides, a normal GPS receiver works on Earth when it receives a signal from four satellites. For the Moon we also had to design a solution where the signal would be received from only three satellites. Even in such cases, the system must work and allow us to determine the position. This is a challenge, and we have to minimise the cost of building the system.

The astronauts who will build this base on the Moon will have to be able to do everything?

Maybe not everything, but their competences must complement each other. The mission cannot rely on one person. Astronauts are already being trained and gathering experience at the International Space Station. There are plans to build a Gateway station that will orbit the Moon and be an intermediate element for landing and travel to the Moon and Mars.

Are visions from sci-fi movies becoming real?

I hope they will become real sooner than in a decade. This plan is very well defined. There are manned missions planned to launch for the Moon from 2024 to 2027. The European Space Agency's navigation system, Moonlight, should already be taking off around 2027, so it really is a close prospect. Before that, we will test whether we can receive GPS or Galileo signals at the height of the Moon, so much further from Earth. The tests will be carried out soon, and the landing of a man on the Moon again is planned for as early as 2025. A total of 250 missions to the Moon are planned over a period of 10 years. The race involves not only the United States, Canada and the European Union, but also China, India, Russia, Japan and Australia. The latter intends to support the systems being built by Europe, the USA and Japan. It is getting dense. And the race itself is being treated with great prestige, especially from the Chinese perspective – they want to showcase its technological advancement.

From these space missions we send out, we know more and more about planets still uninhabited by humans. It seems that some form of life may have existed there, since there are traces of water and ice. Which of course raises questions about the course of evolution that led to the development of life on Earth.

We have traces of organic compounds, however, they are a long way away from proteins and DNA. We have not yet found life or evidence of its existence on other celestial bodies. At the moment Earth is the only such body where this life could have developed and where we have direct evidence of it.

Are scientists able to state with confidence that life is only on Earth, or assume that it also exists somewhere, although not necessarily in the same form as, for example, mammals or reptiles.

More and more planets are being discovered that are very similar to Earth. They are in a realm where life could have developed. They are at the right distance from their parent star, which provides the right temperature to keep water in a liquid state. But so far we have no further evidence of biological life on other planets.

Are we alone in the cosmos?

At one time there were campaigns to listen to the universe. We were checking whether there were any radio signals reaching us that could be sent by alien civilisations – so far without success. So it is indeed fair to say that for the moment we are alone. But it is necessary to have some sort of plan B if we destroy our planet. Hence the project to build a moon base not only for man to land there and fly back, but to live there. It is possible that he will later take up residence on other celestial bodies, but first we must test all the possibilities and technologies as close to Earth as possible. This is achievable even though it is extremely difficult.

Why is it difficult? After all, Armstrong landed on the moon. 

And that's why we think it's so easy today. Meanwhile, space technology, extraterrestrial technology is extremely sensitive and fragile, and is still a huge challenge. The first car was only built less than 140 years ago. More than 50 years ago, man landed on the moon. There has been a huge leap in civilisation over the years, but it is still the case that we are able to repair a car on Earth, we can refuel it, and there is no particularly big limit to the weight of a car. However, when it comes to space technology, there is a limit to the amount of fuel we can use - there has to be enough to lift off from the Earth, reach the Moon, decelerate there, land, lift off again and return to Earth this time. Each kilogram of such a spacecraft is worth hundreds of thousands of dollars, and any repair under space conditions is extremely difficult if possible at all. So everything has to be anticipated and planned in advance, and this is an extremely difficult task.

Is Einstein's equation similar in importance to the Copernican breakthrough? Even if we don't understand it at all, many of us feel that it is something special.

And rightly so, because it has given us a different perspective on gravity and the forces that act between celestial bodies. Einstein, with the publication of the general theory of relativity, also changed our perspective of how we look at things – he showed that gravitational forces are not exactly forces as we understood them before, i.e. in the Newtonian way. Instead, the motion of celestial bodies is governed by the curvature of space-time.

That's a bit of philosophical.

Yes, because space-time has four dimensions – three are spatial, one is time. The celestial bodies move the way space-time is curved, and space curves according to how energy and mass are distributed in the universe. Einstein's equation tells us about geometry and motion on the one hand, and the distribution of energy and mass on the other. It was also revolutionary; Einstein, in fact, was surprised by some of the consequences that flowed from his theory.

For example, what?

His theory allowed for the fact that the universe was expanding. He didn't like this and added a special element to his equation, the cosmological constant, which made the universe not expand and stable. But when it was discovered that it was expanding after all, Einstein had to correct his equation and delete the cosmological constant. Today we return to it because it turns out that the universe is expanding, but in an unexpected way. To explain some of the expansion of the universe, dark energy is necessary. Nobody knows what it is, but it is very easy to reduce it to Einstein's equations as he did, that is, using the cosmological constant.

With breakthroughs like this, do you need a flash of genius, the courage to step outside the pattern in which you grew up? Deduction, analysis or illumination?

In the case of Copernicus and Einstein, much was based on theoretical consideration. Today, we have theorists who try to create new theories to explain various phenomena. And we have practitioners who use advanced technology to make these theories verifiable. Ideally, one goes hand in hand with the other, because sometimes, with advanced technology, we are able to observe something that does not fit with current theories. And then theorists have to come on stage to explain what we have observed.

And what, for example, has been verified this way?

The aforementioned cosmological constant and the expansion of the universe – we are able to observe these using various methods. A few years ago gravitational waves were observed, which allowed us to look at the universe from yet another perspective. Up until now, we have viewed the universe using electromagnetic radiation, i.e. radiation in different ranges: visible light, infrared, radio waves, and so on. Now we have started to observe the universe using gravitational waves, but to produce them we need to have very special cases of interactions of very massive celestial bodies, e.g. the merger of two black holes or a black hole and a neutron star. When these interactions are strong enough, the gravitational waves that we are able to observe on Earth are produced.

Knowledge is constantly expanding thanks in large part to technology which ...

... shows that had Copernicus had other tools, it is possible that he would have discovered much more. Technology alone, however, is not enough. You still need people who know how to use it.

Does the modern scientist feel humbled by the world they are exploring on a molecular and cosmic level?

Scientists usually deal with a very narrow field when conducting their research. Now human knowledge is so broad that it is difficult to be a Copernicus. No one is a doctor, lawyer, cartographer, or astronomer at the same time.

And an astrologer. In the time of Copernicus, astrology was treated on a par with astronomy, and horoscopes were put to more than just kings.

This is now a thing of the past, especially since the astrological signs of the zodiac today do not agree with the arrangement of the stars. They were established in ancient times, when the arrangement of the stars was different. If someone thinks they are a Virgo, they are actually an astronomical Leo. All the constellations of the zodiac are shifted by about one cycle from what they were in antiquity. This is due to the precession of the Earth's figure. The Earth's axis, due to the interaction of the Sun and the Moon, moves over a very long period of about 26,000 years. This axis has not always pointed towards the North Star, Polaris. It is now gradually moving away from this star. Moreover, the constellations of the zodiac were 13, not 12. The Serpentine, which was between Scorpio and Sagittarius, was deleted. So let's put astrology aside.

Why did you choose science?

When I was finishing my studies, I felt a lack of knowledge. I was studying computer science and simultaneously doing my PhD. I wanted to learn more. And that's why I then got into scientific research. And believe me, a scientist who doesn't learn all the time is a poor scientist.

interview by Katarzyna Kaczorowska

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