Most alien civilizations scattered across our Milky Way galaxy probably self-destructed. This is the conclusion of a recent study that mapped the rise and fall of extraterrestrial civilizations over billions of years since our galaxy formed.
This finding can be seen as the latest update to the famous “Drake equation,” which estimates how many alien civilizations might exist in the Milky Way.
Created by astronomer Frank Drake in 1961, this famous equation uses seven variables to estimate the number of civilizations in the galaxy we might communicate with. These include the average rate of star formation per year, the chance that a civilization develops detectable technology, and how long such civilizations emit signals into space.
However, a new study by physicists at the California Institute of Technology offers a more realistic approach than the Drake equation. It predicts where and when life is likely to occur in the Milky Way and identifies a crucial factor: the tendency of alien civilizations to self-destruct.
“Since the Hubble Space Telescope and Kepler Space Telescope, we have gained extensive knowledge about gas and star density in the Milky Way, star formation rates, exoplanet formation, and the frequency of deadly supernova explosions,” said Jonathan H. Jiang, an astrophysicist at NASA’s Jet Propulsion Laboratory and co-author of the study.
The researchers considered factors influencing civilization development, such as the prevalence of sun-like stars with Earth-like planets, the frequency of lethal supernova radiation, and the probability and time needed for civilizations to evolve under suitable conditions.
Using these factors, scientists modeled the Milky Way’s evolution over time and space. They found the highest chance for life to appear is about 13,000 light-years from the galactic center, roughly 8 billion years after the galaxy formed.
For comparison, Earth is about 25,000 light-years from the galactic center, and human civilization emerged around 13.5 billion years after the Milky Way formed, although simple life appeared shortly after Earth formed.
In other words, we might be a “frontier civilization” in terms of galactic geography. Our civilization is also a late bloomer compared to others that may have existed long before us.
Of course, if life is still emerging across the galaxy, many civilizations may exist that we haven’t detected yet. These civilizations likely cluster around 13,000 light-years from the galactic center, where sun-like stars are most common.
According to the researchers, most civilizations still around today are probably quite young. It usually takes a very long time for a civilization to arise, grow, and then self-destruct for some reason. This means civilizations that formed during the “golden age” over 5 billion years ago likely destroyed themselves long ago.
This self-destruction factor is a key variable in the California Institute of Technology model, based on the question: why do civilizations in the galaxy tend to self-destruct?
The study suggests that if factors like nuclear war or climate change are included, most civilizations that existed before us probably didn’t survive to the present.
Source: Live Science
