Most extraterrestrial civilizations that once scattered throughout our Milky Way galaxy have likely self-destructed. This is the result of a study recently published, after researchers mapped the emergence and disappearance of extraterrestrial civilizations over billions of years since our galaxy formed.
Accordingly, this result can be seen as the latest update to the “Drake Equation,” which is used to estimate the number of extraterrestrial civilizations in the Milky Way.
Created by astronomer Frank Drake in 1961, this famous equation is based on seven variables to calculate the number of civilizations in the galaxy that humans might contact, such as the average rate of star formation per year in the galaxy; the probability of a civilization developing technology to the extent that their signals could be detected in space; and the duration over which such a civilization emits signals into space, etc.
However, the research just conducted by physicists at the California Institute of Technology is much more practical than the Drake Equation. This study indicates where and when life is likely to occur in the Milky Way. At the same time, it also helps identify the most crucial factor: the tendency of extraterrestrial civilizations to self-destruct.
“Since the Hubble Space Telescope and the Kepler Space Telescope, we have gained a lot of knowledge about gas and star density in the Milky Way, the rate of star formation, and the rate of exoplanet formation… or the occurrence rate of supernova explosions,” said Jonathan H. Jiang, an astrophysicist at NASA’s Jet Propulsion Laboratory and co-author of the study.
The researchers examined a range of factors believed to influence the development of a civilization, such as the prevalence of sun-like stars with Earth-like planets; the frequency of supernova explosions emitting lethal radiation; the probability and time required for civilizations to develop if conditions are favorable.
Based on these factors, scientists modeled the evolution of the Milky Way over time and space. As a result, they found that the probability of life appearing peaks at about 13,000 light-years from the galactic center, and approximately 8 billion years after the Milky Way formed.
By comparison, Earth is about 25,000 light-years from the galactic center, and human civilization appeared around 13.5 billion years after the Milky Way formed, although simple life forms emerged shortly after the planet formed.
In other words, we might be a “frontier civilization” in terms of galactic geography. Moreover, our civilization is also considered ‘late-born’ compared to other civilizations, which may have formed long before us.
Of course, assuming that life is still continuing to ‘arise’ throughout the galaxy, there are likely many other civilizations out there that we have yet to discover. These civilizations may primarily be concentrated around an area 13,000 light-years from the galactic center due to the prevalence of sun-like stars here.
According to the researchers, most civilizations currently existing in the galaxy are probably still quite ‘young’. Typically, it takes a very long time for a civilization to arise, develop, and eventually perish for some reason. Of course, this also means that civilizations formed during the ‘golden time’ over 5 billion years ago likely self-destructed long ago.
In fact, this is also an important “variable” in the model of the researchers from the California Institute of Technology, based on the question: What causes civilizations in the galaxy to often self-destruct?
Accordingly, if factors such as nuclear war or climate change are applied to the model, it is highly likely that most civilizations that formed before us could not survive to this day.
Source: Live Science