Interview with Professor Jerzy M. Kreiner - astronomer, director of the Institute of Physics at Krakow Pedagogical University, head of the Astronomical Observatory on Mount Suchora in the Beskydy, author of several astronomy textbooks.
Przegląd: There is more and more news that more asteroids are being discovered near the Earth. Should we be afraid of space?
Jerzy Krainer: I would ask the question differently: should we be afraid of drought or rainfall? Cataclysms are different, and you should be prepared for them. In terms of astronomical threats, they are no stronger than they were when we were less able to recognize them. The last case of a collision with a small asteroid is the fall of a small piece of matter in the Urals, near Chelyabinsk. This event received a lot of media coverage. However, each collision of celestial bodies with the Earth is widely covered by the press, and then theories about new asteroids immediately appear.
“Or the old ones are resurrected, like those that explain the extinction of the dinosaurs
“For astronomers, there is nothing special or unexplored about such events. We know of meteorite craters. In our planetary system, this is a very common thing; just look at the moon. It has no atmosphere, and its entire surface is dotted with craters that have arisen from the impact of asteroids that have fallen over the past four billion years. There is atmospheric erosion on Earth, and such traces are being erased, which is why we do not know the oldest craters. And the recent impacts (that is, those that have occurred over the past hundreds or thousands of years) have already been studied and analyzed by geologists quite well.
Notice the danger
Is the news about the approaching asteroids a result of the fact that we have acquired more advanced instruments that are able to see them? Or did they try to hide this kind of information before?
Promotional video:
- This is the result of improving the equipment with which you can notice the approach of some celestial body to the Earth. For this purpose, special programs and systems of telescopes have been developed, which are only engaged in "combing" the sky in search of something that appeared there, moving against the background of other stars and heading in our direction. Of course, the question remains, how to notice it, more precisely, how to notice it in time. In this aspect, the development of computer technology is of enormous importance.
Imagine a situation that there are a million stars in a photograph that look like points of light. Which of the objects that at first glance resembles a faint star can threaten us? How to find out? This can be done by photographing the same area of the sky at intervals of several hours or days, and then comparing whether any of these points have moved relative to the others. Then you need to make calculations as quickly as possible in order to understand whether the path of this object can intersect with the Earth's orbit.
How early can astronomers warn earthlings about a possible or expected serious collision?
- It is impossible to answer this question directly, although there is a certain pattern. The larger the object threatening us, the easier it is to notice it from a distance. Small blocks, a couple of tens of meters in diameter, we usually notice at the last moment, but - a small object - little damage. For an asteroid several hundred meters in diameter to fall into the center of a large city, one must be very unlucky. Objects that could cause a global catastrophe are identified in a timely manner.
The probability that some really large asteroid will collide with the Earth is incredibly small, because, practically speaking, all these bodies move around the Sun, and we know their orbits. Therefore, in the future of several tens or several hundred years, we do not expect a collision of the Earth with some large cosmic body. So far, we do not know such an object, but this does not mean that something similar can come to us from space. But, as I said, the probability is very small.
How can a collision be prevented?
- It's problematic. The methods depend on the size of the object. The most realistic option is to launch rockets with nuclear charges towards such an asteroid so that the explosion changes the trajectory of the flying body. It will receive a small impulse and bypass the Earth at a safe distance (a couple of thousand kilometers). This is possible because the computer power available now makes it possible to very accurately calculate the trajectory of such an object. Previously, the calculations would have taken many hours, not to mention the fact that their accuracy would not be very high. Modern computers make it possible to quickly determine if there is a real danger.
- There is also an idea to smash such asteroids with missile strikes
- In principle, this concept has already been abandoned due to the risk and high cost of such an operation. It takes incredible energy to shatter an asteroid, and the question remains whether the debris would have fallen to the ground.
New data in textbooks
Did we learn something about space that made it necessary to rewrite textbooks and books on astronomy?
- Books 80-100 years ago are almost entirely outdated. If we take, for example, the textbook “General Astronomy” by Professor Eugeniusz Rybka on the shelf here (first edition - early 50s), we can say that this science has changed incredibly.
In what sense?
- First, the understanding of the structure of the entire universe has changed. Second, to name only a few things, our knowledge of the solar system has undergone significant changes over the past 50 years. Start with the moon. 12 astronauts walked along it, there are a lot of photos. More recently, in the 19th century, science fiction books wrote that the dark side of the moon is covered with dense forests in which mysterious creatures live. We were able to take close-up photos of all the planets in the solar system. On Mars, Venus and one of Saturn's moons, Titan, space probes landed.
- Recently, the search for extraterrestrial civilizations has become a fashionable topic
- This is a very media topic that appeared in the early 90s, when the first planet outside the solar system was discovered. Only 20 years have passed, and during this time several hundred planets have been discovered, circling around other stars. About a thousand more similar discoveries await confirmation.
At any time, we can detect a planet with parameters similar to those on Earth. We already know the planets similar to the Earth, but not all indicators coincide. Perhaps in 50 years or even earlier we will find some form of extraterrestrial life.
Is there international rivalry in space, or can we say that the powers that be of this world have understood that cooperation bears more fruit?
- It was possible to talk about a clear rivalry until about the 70s, this was reflected in the lunar race, which the Americans won. The space competition between the Soviet Union and the United States cost a lot of money, and as a result, both sides realized that more could be achieved by joint efforts. American astronauts have worked on space stations with Russian colleagues many times, and international crews have increasingly become involved in space research.
Of course, the leading position is occupied by American scientific equipment, but in rocket technology, Russia is the leader. As a result, such situations often develop when American devices fly into space on Russian rockets. So the element of political rivalry faded into the background, although it certainly does exist, especially since the European Union and China have joined it.
Do you follow reports or publications about UFOs?
- No, I don't. It would be too presumptuous to say that there are no phenomena that we do not know about. They probably are. If we knew about them, we would not call them "unidentified". If we trace the recorded facts of UFO sightings, discarding those in which signs of falsification, it turns out that the overwhelming number of these objects were, for example, meteorological probes, the result of military tests, or very bright meteors.
However, there is a small percentage of phenomena that we cannot explain. I still doubt that these are little green men who flew in on a rocket and are circling above us, and I am inclined to think that now incomprehensible phenomena in the near future will be gradually explained.
Is astronomy turning into a science looking for other civilizations?
- No no! In the broadest sense, the goal of astronomy is to observe phenomena in space and formulate the laws governing them, and in addition, to come to an understanding of the essence of cosmic matter. The search for extraterrestrial civilizations is only a separate (and by no means the most important) area of astronomical research. Although this topic always arouses wide interest and resonates in the media.
Most of the problems that astronomers are working on, including the questions studied at our department, are completely uninteresting for the overwhelming mass of the population and the press. Who is interested in the non-radial pulsation of a special type of stars? People are not interested in this, because, roughly speaking, it has nothing to do with their salary or vacation. And how exciting it is to think that thinking creatures live somewhere, who have everything better than ours!
Does the interdisciplinary research of astronomers, geneticists, biologists and other scientists lead to the conclusion that life in space does not necessarily have the same form as on Earth?
- Sure. There are special research groups for astrobiologists, and there are more and more of them. The results of their work provide a lot of topics for discussion with philosophers. Most important is the answer to the question: is our civilization lonely in the Universe, or are there many similar civilizations there? There is, of course, no answer to this question: neither astrobiologists nor philosophers put forward arguments for or against.
If we accept that our civilization is not the only one, what does this change for philosophers?
- I don't know if it changes anything. This statement is still very far away: we realize that the emergence of life on Earth, and especially civilization, was extremely unlikely from the very beginning of the existence of the Universe. You can talk for a long time about the series of conditions that contributed to the origin of life. For example, for 4.5 billion years, our planet had to revolve around the Sun in a more or less circular orbit. If the orbit was an oblate ellipse, that is, if the Earth either approached the Sun, then moved away from it, everything on it would first burn out and then froze out.
Many scientists believe that the emergence of life in the universe is a completely exceptional phenomenon. Do they provide any evidence? No. Others say this: there was a thunderstorm yesterday, and it was not the last, which means that natural phenomena are repeating. Why, then, such a phenomenon as life, cannot arise elsewhere? But even this is impossible to prove. Temporarily: while technology does not allow us. However, it is quite possible that there is another planet in the Universe that resembles the Earth, on which life appeared.
Newton, Einstein …
If we assume that such a planet exists, and on it there is a civilization that is at a lower stage of development than we do, what should be reported to it, what should we warn against?
- I cannot answer this question, it would be science fiction, conversations over a cup of tea. An astronomer makes observations, discovers something based on the level of contemporary science, tries to find some generalizations, rules. Thinking about “what if” is very entertaining, but this is not the business of astronomers.
And when an astronomer meets something that he does not understand?
- That patiently observes this phenomenon or problem and tries to understand them. For this, hypotheses are created, theories are developed, mathematical models are constructed, and then time checks whether we understood certain things correctly. Someone can offer a more successful theory, someone - to develop a more perfect mathematical model, and so we can come closer to understanding the essence of the mysterious phenomena for us today. However, we will probably never be able to get to the full truth.
Newton discovered the rules that we call Newton's laws today, and they seemed to perfectly describe the phenomena in mechanics. But then Einstein proved that these principles only work approximately, and the complete picture is given by the so-called special theory of relativity.