According to a new study, the galaxy containing Earth’s solar system is littered with former alien civilizations which may have wiped their own existence from the Milky Way.
In a new study led by a team of Caltech scientists and one high school student, the team has used statistical modelling and modern physics to understand the emergence of intelligent life and its death across the expanse of the Milky Way. The paper pinpoints where and when intelligent life is most likely to occur in the galaxy, and most importantly, what affects its existence; the predisposition of intelligent creatures towards self-destruction. The team analysed various factors such as prevalence of Sun-like stars giving refuge to planets like the Earth; frequency of lethal, radiation-filled supernovas; probability of intelligent life and time needed for its evolution; and the likelihood of advanced civilizations to self-destruct, which are presumed to contribute to the development of life.
A model of the Milky Way’s evolution, keeping in mind the aforementioned factors, led the team to conclude that likelihood of life emerged at a distance of around 13,000 light years from the center of the galaxy, and around 8 billion years following the galaxy’s formation. Earth is approximately 25,000 light years from the supermassive black hole at the center of the Milky Way and human civilization emerged 13.5 billion years following the galaxy’s formation. The authors also note that simple life came into being soon after Earth formed. These findings suggest that humans are latecomers to this self-aware galaxy. However if we assume that life emerges relatively often and evolves into intelligent beings, there could be more civilizations, most likely surrounding the 13.51 billion years old band of light.
These civilizations are likely to be young as the probability of intelligent life eradicating itself over longer periods is high. Researchers found that even if the galaxy reached its civilizational peak over 5 billion years ago, civilizations which were around may have self-annihilated. It is not clear how often civilizations kill themselves, however the paper successfully determines how extensive civilizations are.