The Milky Way Could Be Teeming With Dead Civilizations

It is a recurring question in our minds and one that we try to answer: Are there other intelligent life forms in the universe - besides humans - capable of founding a civilization? There are many theories that try to explain the absolute lack of alien signals. For example, a recent study has concluded that intelligent life could have appeared several times in the Milky Way , but the vast majority of these civilizations would have become extinct. That is, most civilizations that once dotted the galaxy would have likely ended up self-destructing.

Are we so unique and special?

Most doubt it . Since there are countless stars in the Milky Way and countless galaxies in the universe, there must be other civilizations out there. It's quite possible that we're not the only ones adrift in the terrifying darkness of outer space.

Dead civilizations?

To reach this conclusion, a team of researchers from the California Institute of Technology, NASA's Jet Propulsion Laboratory, and Santiago High School used astronomy and statistical modeling to try to calculate how much intelligent life might have been. living in our galaxy. They applied Drake's equation of searching for extraterrestrial intelligence, to discover when and where intelligent life was most likely to live before they ended up self-destructing within a specified period of the last 8 billion years. This famous equation was popularized by the legendary science popularizer Carl Sagan during his "Cosmos" series.In the new work, the authors analyzed a number of factors believed to influence the development of intelligent life , such as the prevalence of Sun-like stars that host Earth-like planets; the frequency of deadly supernovae emitting radiation; the probability and time required for intelligent life to evolve if conditions are optimal; and the possible tendency of advanced civilizations to self-destruct.

"While no evidence explicitly suggests that intelligent life will eventually annihilate itself, we cannot a priori exclude the possibility of self-annihilation," the scientists state. "As early as 1961, Hoerner (1961) suggests that progress in science and technology will inevitably lead to complete destruction and biological degeneration, similar to the proposal by Sagan and Shklovskii (1966). This is supported by many previous studies that argue that the self-annihilation of humans is highly possible through various scenarios including, but not limited to, war, climate change and the development of biotechnology. "

The results

The data showed that the probability of life emerging peaked about 13,000 light years from the galactic center and 8 billion years after the formation of the Milky Way, so we could assume that life appears reasonably often. and eventually it becomes intelligent (we are about 25,000 light years from the galactic center, and human civilization emerged on the planet's surface about 13.5 billion years after the formation of the Milky Way).

Keep in mind that our Sun has nothing special either: it is young, medium in size and similar to billions of stars in our galaxy. It is also believed that there are between 100 and 400,000 million planets in the Milky Way and considering that at least intelligent life has appeared on one of them, the Earth, it is reasonable to consider that there should be other types of intelligent life in some another part of the cosmos.

Thus, according to the researchers, most of the civilizations that have appeared before us are probably self-annihilating. Other civilizations that are still active in the galaxy may be very young, due to the propensity of intelligent life to eradicate.

“Since we cannot assume a low probability of annihilation, it is possible that intelligent life in other parts of the galaxy is still too inexperienced to be observed by us. Therefore, our findings may imply that intelligent life may be common in the galaxy but is still young, which supports the optimistic aspect for the practice of SETI (search for extraterrestrial intelligence), ”they conclude.

But how often do civilizations self-destruct? It is the variable with the most uncertainty of the work and, possibly, the most important in determining how widespread these civilizations are.

Reference: A Statistical Estimation of the Occurrence of Extraterrestrial Intelligence in the Milky Way Galaxy Xiang Cai, Jonathan H. Jiang, Kristen A. Fahy, Yuk L. Yung Arxiv 2020 arXiv: 2012.07902 [astro-ph.GA]