A new version of the famous Drake equation, which calculates the number of alien civilizations in the Galaxy, indicates that the probability of the existence and contact of advanced aliens in our space district is vanishingly small, scientists write in an article published in the journal Astrobiology.
In the 60s of the last century, the American astronomer Francis Drake developed a formula that allows you to calculate the potential number of existing alien civilizations, based on the parameters we know - the rate of formation of new stars, their current number in the galaxy, the number of planets, including Earth's "twins", as well as a number of parameters concerning the aliens themselves.
“The answer to the question of whether advanced alien civilizations exist has always depended on three big uncertainties in the Drake equation. For example, we knew how many stars there were, but we did not have data on the number of planets and how many of them could support life. In addition, we do not know how often life arises, how often it becomes intelligent and how long it lasts before extinction, - said Adam Frank (Adam Frank) from the University of Rochester (USA).
Frank and his colleague Woodruff Sullivan (Woodruff Sullivan) tried to refine the Drake equation using data on the number of exoplanets, "Earth twins" and their habitability, collected by the Kepler telescope over the past five years in orbit. This, scientists say, allows you to get rid of the first uncertainty.
The second and third uncertainties - the likelihood of the evolution of intelligent life and the time of existence of civilizations - can be eliminated by resorting to scientific "pessimism", or, in other words, by acting on the contrary.
As Sullivan and Frank say, we can calculate not these probabilities, but the opposite thing - the chances that we are the only developed civilization in the Galaxy or in the Universe, and the probability that only on Earth could life evolve from the level of bacteria to intelligent people.
Using Drake's refined formula, scientists have calculated the probability that humanity is lonely in the universe. The chances of this happening are astronomically small - it can only happen if the chance of intelligent life developing on an arbitrary planet is one in 10 billion trillion. Therefore, according to Frank, it is likely that intelligent life in the Universe and in our Galaxy appeared before us.
On the other hand, the complete Drake equation gives less optimistic estimates - as the calculations of the authors of the article show, those civilizations that have already appeared in the Milky Way and in neighboring galaxies for the entire lifetime of the Universe, 13 billion years, have already disappeared if the typical periods of their existence comparable to the lifetime of mankind. Nevertheless, we can now say with confidence that the remains of such civilizations, in principle, can be found in the future.
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“There is a fundamental question - did life arise anywhere else? Now we can give an empirical answer to it for the first time, and, surprisingly, it is extremely likely that we and our era are not the only place in the history of the Universe when intelligent life arose,”concludes Frank.