If you say that you believe in the existence of aliens, it is unlikely that your friends will be greatly shocked by this. In a universe of 2 trillion galaxies, one must be highly narcissistic to believe that man is the only intelligent being. One 2015 U. S. poll found that about 54 percent of Americans believe in the existence of extraterrestrial intelligence.
Perhaps their optimism stems from the influence of science fiction. After all, if there are no aliens, what about the Starship Enterprise mission from the Star Trek series or the opening of jobs for Vulcans (a fictional alien race from the same series). And yet, fiction aside, many scientists today agree that space undoubtedly contains a great many interspersed with life, and intelligent life.
However, can we say something about life in the universe? Can we venture to guess how far away the nearest intelligent aliens are from us? This question has occupied scientists for decades. In 1961, astronomer Frank Drake developed a simple equation to estimate the number of "technically active" civilizations in our galaxy. This simple mathematical formula is considered the second most famous in science after Einstein's equation E = MC2.
If you look at this formula, it's easy to see that it takes into account a number of factors, including the likelihood of habitable planets around stars, the likelihood of life emerging, and the likelihood that simple life forms evolve in such a way that intelligent beings will eventually appear. But even without trying to make calculations based on the Drake equation, we can use similar reasoning to estimate the number of extraterrestrial civilizations and the distance separating us from the nearest Klingons (a fictional alien civilization of humanoid warriors from the science fiction universe of "Star Trek").
We start with recent studies that have shown that one in six stars has a habitable planet. Not one in a million, but every sixth. So, let's take this number as a basis and continue. We must make a few assumptions. In particular, to decide which part of the planets, similar in size to the Earth, has ever become home to technically advanced inhabitants.
Life on our planet originated rather quickly: a random chemical reaction in 1.5 million trillion cubic meters of ocean water gave birth to a reproducing molecule within just a few hundred million years. Hence it follows that not so much is needed for the origin of life. Then, it can reasonably be assumed that at least half of all habitable planets sooner or later gave rise to some form of life.
With intelligence it is somewhat more complicated. The dinosaurs were well constructed, but not very successful in school. And yet, let's assume that one of the 100 planets on which life exists will eventually be marked by the emergence of intelligent beings. And, according to Frank Drake, suppose also that any aliens will be able to hold out on their planet for 10 thousand years, until they destroy themselves (nuclear war, man-made ecological disaster, or something else like that) or meet their sad end for some other reason.
Performing simple arithmetic calculations, we will find that in each of the 100 million star systems there is a technically advanced civilization. This is not much different from the likelihood of hitting the Powerball jackpot next week.
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So, how close are the nearest aliens to us, sending signals of their existence? If we pay good money for a superluminal hyperspace drive and visit our neighbors, how far will we have to fly from Earth? Well, the average distance between stars in our part of the Galaxy is 4.2 light years (the distance to the star Proxima Centauri). That is, in each cube of space, the edge of which is 4.2 light years, there is, on average, one star. Now let's imagine a large cube with an edge about 2,000 light years. It will contain about 100 million star systems and somewhere among them - one developed civilization.
Based on these rough and not particularly careful calculations, it can be assumed that the nearest "aliens" are located at a distance of one to two thousand light years. In other words, no closer than the three bright stars in Orion's belt. Of course, neighbors can be much farther, or closer. But this order-of-magnitude estimate tells us that they clearly do not live in the neighborhood. They do not hear our news reports and it is unlikely that they have any motive for visiting us. They just don't know anything about our existence.
By the way, most likely, we will not be able to visit them either. The fastest rockets today would take roughly 20 million years to get there, and by that time even the most daring astronauts are likely to be terribly tired of government food and other inconveniences of flight.
Yes, alien civilizations most likely exist, and in our galaxy alone there can be up to 10 thousand of them, not to mention millions of other galaxies. Perhaps they are quite far from us. But still, they can be found. That is why people persistently continue to comb the sky in search of radio signals that were broadcast by our brothers in mind from time immemorial.
Igor Abramov