Extraterrestrial life - fantasy or reality?

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

The character of the cult television series The X-Files, FBI Special Agent Fox Mulder, is convinced of the existence of intelligent life outside the Earth and that representatives of extraterrestrial civilizations have visited our planet more than once. Agent Mulder's partner, FBI Special Agent Dana Scully, did not share her colleague's views, questioning his extravagant ideas. The arguments between two FBI agents are a great example of how all information about aliens should be taken - with a great deal of skepticism and purely from a scientific point of view. And if in the universe of "X-Files" aliens really exist and are trying to take over our planet, in reality things may be very different.

Regardless of our beliefs and desires, there is an objective reality: our home - planet Earth, is located in the solar system in the Milky Way galaxy, which cuts through the vastness of the infinite universe. And in the Universe, as we know today, the same laws of physics operate as on Earth. Science has helped answer difficult questions about the world and our place in it, and it is science that is our guiding star in attempts to find an answer to the question of whether we are alone in the universe.

Fear of loneliness

Almost five hundred years have passed since Nicolaus Copernicus launched the scientific revolution, challenging the general idea that the sun revolves around the earth. During this time, a lot has happened. So, thanks to the development of technology, we were able to first consider the celestial bodies closest to us, and then completely go beyond our own planet. We sent robotic vehicles into space, made Mars the only planet in the solar system inhabited by robots, and discovered hundreds of planets around other stars. Just think - there are thousands of distant worlds, most of which are probably uninhabited. But if you and I appeared, it is possible that among the countless number of worlds there will be at least one inhabited by intelligent beings. At least we really want to believe it. However, no matter how we peer into the sky, we still do not know if there is anyone else there. Nevertheless, in attempts to find an answer to the famous question of the Italian physicist Enrico Fermi "where is everyone?" it is necessary to clearly separate reality from fantasy.

Where did life come from in the universe?

Outer space is the main chemical factory that began operations immediately after the Big Bang. The three lightest elements - lithium, helium and hydrogen, as well as the remaining 92 elements found in nature, created stars, including all, without exception, carbon, calcium and phosphorus, which is present in all living organisms on Earth. When stars die, they eject the lion's share of their mass into space and endow the nearest gas clouds with a set of atoms that will enrich the next generation of stars in the future. Thus, all people, planets and moons would not exist if it were not for the remains of the spent stars. It also tells us that rare ingredients are not needed to create life.

In space, the first five places in distribution are occupied by hydrogen, helium, oxygen, carbon and nitrogen. Interacting with each other, these elements made it possible to create the main components of life on Earth. But space is not the most favorable place for molecules that live in massive clouds that envelop the stars. Constant jumps in temperature, supernova explosions and ultraviolet radiation from nearby bright stars can destroy molecules. In order to survive and become part of the particles of cosmic dust and then comets, asteroids, planets and people, the molecules must inhabit relatively calm and sheltered areas. Moreover, for complex molecules to appear, it also takes time.

The most famous complex molecules are glycolaldehyde (hydrocarbon), adenine and glycine. These and similar ingredients are necessary for the emergence of the life we are accustomed to and are found, undoubtedly, not only on Earth. The abundance of chemical elements in the Universe can give rise to life on other planets. Moreover, such planets of the solar system as Jupiter, Saturn and its satellite Titan are extremely rich in chemical elements. In 2005, the Huygens space probe landed on Titan, which gives us the knowledge that the chemical environment on the largest moon, Saturn, is somewhat reminiscent of young Earth. It is for this reason that many astrobiologists consider Titan to be a kind of laboratory for studying the past of our planet. Thus, today, talk about life on other planets has ceased to be the prerogative of madmen. In addition, modern studies of especially hardy organisms - for example, tardigrades - show that life knows no boundaries and no obstacles are afraid of it. To find life outside our planet, scientists must understand not only astrophysics, chemistry and biology, but also geology and planetology, because they are looking for potentially habitable planets everywhere.

How the discovery of exoplanets changed the world

The Nobel Prize in Physics this year was awarded to James Peebles - for theoretical discoveries in the field of cosmology, Michel Mayer and Didier Kelo for the discovery of an exoplanet that orbits a star similar to our Sun. Since 1995 - after the discovery of the famous exoplanet 51 Pegasi b - astronomers have discovered more than a thousand exoplanets in our galaxy. The discovery of 51 Pegasi b revolutionized astronomy and led to exobiology as well as new tools for finding and characterizing observed exoplanets. Needless to say, the more new worlds scientists discover, the greater the public's desire to know if they are inhabited.

For 25 years now, the hype around exoplanets has not subsided. The colossal public interest in distant worlds, of course, was caused by the prospect of discovering intelligent life on them. However, this hype is probably overrated. As astrophysicist and popularizer of science Neil DeGrasse Tyson writes in his book Death in a Black Hole and Other Minor Cosmic Troubles, the newly discovered planets are mainly gas giants like Jupiter and Saturn, which means they do not have a suitable surface for development of life. Again, in our usual sense. And even if the gas giants are inhabited, the likelihood that these living organisms are intelligent is extremely small.

However, most astrophysicists generally agree that life in the universe probably exists elsewhere. It is very simple to substantiate such a position - if our solar system is no exception, then the number of planets in the Universe exceeds the number of all sounds and words ever uttered by representatives of our species. Following this logic, the claim that we are the only intelligent life in the universe sounds rather radical and somewhat improbable. But is everything so clear?

What could life be like outside of Earth?

Let's start with the fact that on our planet alone there are almost millions of species of living beings. If you think about it, it is rather difficult to imagine that jellyfish, algae, beetles, sponges, snakes, condors and giant sequoias come from the same planet. The variety of forms and varieties of living organisms on Earth suggests how amazing life in other worlds can be. We assume this based on the fact that life came about through the interaction of four chemical elements - hydrogen, helium, oxygen and carbon. Therefore, it is very likely that if we ever find life outside of Earth, it will be composed of a similar mixture of elements. However, if alien life is in any way comparable to life on our planet, intelligence seems to be rare. According to some estimates, over 10 billion species have existed on Earth throughout the history of the Earth. Therefore, we can assume that only 1 out of 10 billion of all extraterrestrial species of living organisms will be as intelligent as Homo Sapiens, no more. And this is not to mention the chances that these intelligent beings have high technology and a desire to establish interstellar communication.

But if such a civilization does exist, is it possible to contact it? Astronomer Carl Sagan devoted his entire life to the study of space. One of Sagan's works is the science fiction novel "Contact", in which the scientist describes the most likely contact with representatives of extraterrestrial civilizations from the point of view of science - it will take place with the help of radio waves. The fact is that radio waves are able to cross the galaxy unhindered, penetrating both interstellar gas and clouds of cosmic dust. However, there is one “but” - earthlings figured out the structure and application of the electromagnetic spectrum quite recently, a little less than a century ago. This somewhat reduces the chances that we will catch an alien signal.

It is much more likely, nevertheless, to find simple, unreasonable traces of life in the Universe. And this is more than real, since Mars, Enceladus and Titan are right under our noses. In the next few years, NASA will send several vehicles to them at once, the main task of which is to search for extraterrestrial life. Some astrophysicists are convinced that in the coming decades we will find life outside the Earth. And it will be a sensation anyway.

How to deal with the conflicting claims of scientists?

Considering all of the above, such loud statements by some scientists and the media as “aliens have already visited our planet” or “aliens have colonized the Milky Way” sound rather speculative. It may even seem that they are no better than the statements of people who were allegedly abducted by aliens right from bed and put terrible experiments on them. Nevertheless, one should not rush to conclusions.

Recently, a study was published in The Astronomical Journal, according to the results of which aliens, with a high degree of probability, were already on our planet. Or they are not eager to communicate with us. According to Business Insider, researchers believe that if, in attempts to solve the Fermi paradox, one does not take into account the movement of stars, one of two things remains: either representatives of other civilizations cannot leave their planet, or we are the only technological civilization in the Milky Way galaxy. For this reason, in their work, the researchers assume that stars and planets revolve around the center of our galaxy at different speeds and in different directions. From time to time, stars and planets are close to each other. For this reason, it is possible that aliens are able to travel to places in the galaxy closest to them. But such travels will take a lot of time, so the authors of the work believe that if the aliens have not yet reached us, they could have visited Earth long before our appearance on it.

It turns out that if 1 out of 10 billion species in our galaxy is intelligent and technologically advanced, then the conclusions of scientists seem quite logical. However, we cannot refute the findings of another study, which was carried out by experts from the Institute for the Future of Humanity at the University of Oxford. According to the results obtained, the likelihood that we are the only intelligent life in the observable universe is quite high. Even if we assume that the average number of civilizations in the galaxy can reach hundreds, the probability that we are alone in the galaxy is 30%. Given the conditions necessary for intelligent life to develop, Andreas Sandberg, lead author of the study, told Universal-Sci.com, he and his colleagues concluded that there is a fairly high probability that we are alone in the Milky Way.

Be that as it may, our world and our Universe place is so amazing that the very fact that we try to cognize it and that we … succeed is striking. As for life outside the Earth, peering into the endless cosmic void, it is difficult to assume that there is no one in the Universe except us. After all, we're not that special.