Astronomer Royal Professor Martin Reese is confident that there is no point in fearing an imminent alien invasion
According to the famous British scientist Stephen Hawking, the reason for the alien invasion, most likely, will be the desire to seize the natural resources of the Earth.
“The result may be a situation similar to the one when the Europeans arrived in America. It didn't end well for Native Americans,”says Professor Stephen Hawking.
Dr. Anders Sandberg of the University of Oxford argues that the threat could come from an out-of-control artificial intelligence that will turn the Earth into a heap of rubble. What life can actually be in the Universe and what can you expect from meeting it?
The host of the "Fifth Floor" Alexander Baranov discusses this topic with an astrobiologist, senior researcher at the Physico-Technical Institute. A. F. Ioffe Anatoly Pavlov and biophysicist, lecturer at the University of York Dmitry Pushkin.
Alexander Baranov: Good evening, April 21st, Thursday, 2016. Visiting the Fifth Floor today from Russia is an astrobiologist, senior researcher at the Physico-Technical Institute named after A. F. Ioffe Anatoly Pavlov and biophysicist from England, lecturer at the University of York Dmitry Pushkin. British scientists, who regularly delight us with discoveries, have advised to immediately stop sending signals to other galaxies and sit quietly. What, in principle, can you expect from aliens? Biological life consists of a limited number of elements and is subject to general laws. What framework can rational life in principle not go beyond?
Anatoly Pavlov Scientists can hardly help with this, because science is based on facts and their interpretation, and there are no real facts of contacts with alien intelligence, or even observation of phenomena that could be unambiguously associated with intelligent beings.
AB: Purely theoretically, we have certain facts about which I said. Can you make any predictions based on this?
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A. P.: The problem is that today astrobiologists do not have an unambiguous concept of what life is. We know the signs - that it should be self-reproducing, adapting to the environment, but there is no clear understanding. Say, does cybercivilization apply to life? The life we know is based on carbon chemistry, energy sources (we have a synthesis associated with the sun, bacteria that use chemical energy sources) and a universal solvent that all living organisms use - water. These are rather narrow conditions. We have discussed the so-called "habitable zones" around stars in our galaxy many times. But we are looking, by analogy with us, surface life, in a narrow layer on the surface of the planet. It should also not be forgotten that the first 3 billion years of our planet's existence, life existed at the cellular level. At this level, intelligent life is impossible.
AB: It is unlikely that bacteria and algae will fly to us. Cambridge biologist Simon Maurice argues that the theory of evolution should work wherever there is biological life, and therefore intelligent beings should be very similar to humans - the presence of limbs, certain feelings, the presence of logic, emotions and even ethics. Do you agree?
Dmitry Pushkin. I work in a laboratory where we study unreasonable life. This is a directional choice because this order seems logical to first understand the general processes. How bacteria interact and respond to the world around them, for example. A huge leap from them to intelligent life. Aliens probably have a moral, but if Darwin's laws guarantee it will be like ours, I'm not sure.
AB: The laws of survival should be similar, then morality may be similar. There is also a theory that we simply cannot face a civilization that is many orders of magnitude more advanced. One of the reasons is that life in the universe may have appeared recently. Astrophysicist James Ennis wrote that in the early stages of the development of the universe, there were powerful emissions of gamma radiation, and they could prevent the emergence of intelligent life and biological life in principle. Maybe they even got in the way.
DP: I can only joke about this. This is mostly at the level of science fiction.
AP: I came to astrobiology from astrophysics and I know that there are simple physical limitations. For life, we need a fairly large number of trace elements, which were synthesized in the process of stellar evolution at rather late stages. Then they were thrown out of the stars, for example, in a supernova explosion, or spread by a strong stellar wind, then in the clouds this medium collapsed into the next generation of stars and planetary systems. This process is not fast, and life like ours arises in the later stages of the evolution of the galaxy. But what does “relatively recently” mean? Our technical civilization is generally only a couple of hundred years old. This is a negligible period of time on a galactic scale. And if civilization arose a million years ago, imagine what it could be. These questions are being discussed, but there is no scientific theory yet.
AB: But I really want to discuss. There is another theory about why the universe is silent - there are no signals from advanced civilizations. The theory says that the biological form of life has a time limit for its development, and after a fairly short period of time it should die out. Therefore, she does not have time to evolve enough to make intergalactic flights, or at least correspond with other Morse code. Or is this also pseudoscientific pseudo-theories?
AP: I have already mentioned that for a long time there was no development towards intelligent life.
AB: But now everything has gone quickly, and there is still a billion years of such technical progress - and can we expect something?
AP: It should be understood that there were dozens of global catastrophes in subsequent history. For example, the one that caused the extinction of the dinosaurs. The catastrophes led to a very significant renewal of the biosphere. With the disappearance of dinosaurs, mammals evolved, filled niches, and eventually brought them to us. Why the human mind then arose is also an unresolved question. Why it has become more useful to change the environment, rather than adapt to it, as before, is not clear. But then it began to accelerate, and now the world has completely changed, compared to what it was a few thousand years ago.
AB: Since there is no explanation for this, then it may turn out to be a random phenomenon. And on another planet, life can endlessly adapt to the environment and not change it in any way?
AP: The very existence of multicellular organisms is an unusual fact. It requires a fairly strong energy source. We only exist because we have 20% oxygen in the atmosphere, which is unusual. It is associated with the work of plants, photosynthesis. This phenomenon has arisen for a reason. The famous Cambrian explosion, when evolution from unicellular organisms to huge multicellular organisms took place in 15-20 million years, is associated with some global catastrophes during this period. How typical is this for other planets? The likelihood of such a development cannot be clearly assessed. There are no guarantees. The presence of liquid water on the surface, stars, heavy elements also does not guarantee anything.
DP: I agree. All this can be viewed either with optimism, that something good will come out of this life, or with pessimism. Optimistically, the very fact that life is emerging is a fact of a cosmic scale. We talked about the time scales of our galaxy, for example, but you can look at the time scale of our planet. The planet is about 4 billion years old, and life appeared here already about 3 billion years ago, that is, life on the planet existed most of the time. It does not have to develop into a highly organized form, but the Universe is large, there are many different possibilities, so it seems that somewhere a highly organized life should develop. This paradox was first formulated, it seems, by the physicist Fermi: if these factors are added together, it turns out that there should be quite a lot of life in the universe, then why don't we see them?
AB: Even from the point of view of the theory of large numbers, there should be an infinite number of civilizations.
DP: When I got acquainted with these theories, I saw the Drake equation (the theory of the 50s-60s): what is the number of civilizations with which we can come into contact. This is not a very strict theory, but simply taking into account various factors from the point of view of the theory of probability. This includes the average rate of formation of stars, multiplied by the probability of finding a planet near the star, by the probability of finding a planet that can support life, and so on. I am a physicist by my first education, and I immediately felt that something was wrong there. The first factor is about speed, and the left side of the equation is about number. The speed depends on the time, but the number does not. Among the terms of this equation there must be a factor proportional to time. It is the last in Drake's formula and is denoted by the letter L. This is the lifetime of a civilization. So it is possible that L is not that big. This is how the Fermi paradox can be resolved. The development of civilization can be dangerous.
AB: And this is Freeman Drake, who promoted the theory of the shell around the Earth?
DP: You mean Dyson.
AB: Yes, this is also an interesting theory. Freeman Dyson promoted the idea that when a civilization is really seriously developed, it can create a shell around a star system that will keep all the energy inside, and it will be utilized as efficiently as possible, so in some parts of the universe we do not see stars. It seems to me that this is from the realm of fantasy.
AP: Yes, but there is some logic in this. It seems that Nikolai Kardashev, a physicist, who once introduced a classification of civilizations by the level of their development, dividing them into 3 main types according to the main parameter - the amount of energy they use. Civilization 1 uses an amount of energy comparable to the energy resources of the planet on which it lives. Civilization 2 uses the energy resources of the solar system. And a level 3 civilization harnesses the power of the galaxy. Civilization 2 must capture energy, hence the need for a sphere. And in these black places there will be no holes, but a different kind of radiation.
AB: On the Kardashev scale, do we need to wait for type II or III aliens? Should I be quiet just in case?
A. P.: Why should hypercivilization take over the Earth? They might as well use the Moon or some other similar object. We are not very interesting for very advanced civilizations.
AB: They are interested in us as much as the bacteria that Dmitry studies in his laboratory. Should we be afraid?
DP: You should never be afraid at all. Better to try to find out as much as possible, this is the best tactic.