I’ve noted an odd lag in our cultural understanding of the probability of advanced alien civilizations in our galaxy and the universe at large, and the bearing of recent scientific discoveries upon this pivotal subject.
Most people still seem to be operating under the limited and now very dated knowledge of the 1970s, rather than the modern status of the scientific data in the keys areas of; the prevalence of warm and potentially inhabitable Earth-like worlds, the distribution of water and amino acids throughout the stars, exoplanetary composition, and the relative age of other star systems like our own. In recent years all of the rapidly advancing scientific findings in these areas have been converging on an entirely new estimation of the prevalence of life and advanced alien civilizations in the universe. So I wrote the following summary earlier today and I thought that some folks here might enjoy reading it, and perhaps we can discuss these and other findings which have reshaped the nature of the debate regarding the extraterrestrial hypothesis:
Our culture seems to be lagging behind the scientific data, when it comes to the subject of warm and potentially living Earth-like worlds in the universe - apparently culture has some kind of cognitive inertia. Because the idea of extraterrestrial life, or even intelligent extraterrestrial life with interstellar spaceflight capability, used to seem improbable to many people before we had the results of the Kepler Mission, and before we knew about the ubiquity of water and amino acids throughout the universe, and before we understood the dynamical evolution of planetary systems and before we knew the age of the solar system relative to other star systems. Now all of that has changed. Today, we know that there are over 40 billion warm Earth-like worlds in our galaxy alone, and over 40 billion trillion warm Earth-like worlds in the observable universe alone (which is in turn only a speck of the entire universe), moving through stellar systems chock full of water and the building blocks of life (and we now know that life appeared on the Earth pretty much as soon as the Earth cooled down enough to support carbon-based life).
So now the odds are extremely favorable toward a model of the universe that's teeming with life, and we have no reason left to presume that it's at all rare. The only remaining question is the prevalence of intelligent life, and even on that question we have no logical reason to presume that the evolution of intelligent life is extremely rare. Seventy years ago it wasn't totally unreasonable to wonder if there were any other intelligent civilizations out there in the universe. But today, the most reasonable scenario appears to describe our galaxy as a system lushly populated with organic life, and probably thousands or more planets inhabited by technological civilizations, most of which are probably many millions or even billions of years ahead of us, because most of the inhabitable planetary systems in our galaxy are much older than ours:
"We found that most potentially habitable star systems are much older than the Sun and located farther from the galactic centre. By comparing the ages of these systems we estimated that ~77% of potentially habitable star systems are on average ~3.13 billion years older than the Sun. This suggests that any intelligent life in the Galaxy is likely to be incredibly more advanced than we are assuming that they have evolved under similar timescales than we have."
"The Age Distribution of Potential Intelligent Life in the Milky Way," Daniel Legassick, 2015
In light of these newly discovered facts, it would be a far greater mystery if our planet weren't being visited by alien civilizations from time to time. Fermi was perfectly correct to ask the question "Where is everybody?" He should've looked up, because the answer appears to be: "all around us."
Most people still seem to be operating under the limited and now very dated knowledge of the 1970s, rather than the modern status of the scientific data in the keys areas of; the prevalence of warm and potentially inhabitable Earth-like worlds, the distribution of water and amino acids throughout the stars, exoplanetary composition, and the relative age of other star systems like our own. In recent years all of the rapidly advancing scientific findings in these areas have been converging on an entirely new estimation of the prevalence of life and advanced alien civilizations in the universe. So I wrote the following summary earlier today and I thought that some folks here might enjoy reading it, and perhaps we can discuss these and other findings which have reshaped the nature of the debate regarding the extraterrestrial hypothesis:
Our culture seems to be lagging behind the scientific data, when it comes to the subject of warm and potentially living Earth-like worlds in the universe - apparently culture has some kind of cognitive inertia. Because the idea of extraterrestrial life, or even intelligent extraterrestrial life with interstellar spaceflight capability, used to seem improbable to many people before we had the results of the Kepler Mission, and before we knew about the ubiquity of water and amino acids throughout the universe, and before we understood the dynamical evolution of planetary systems and before we knew the age of the solar system relative to other star systems. Now all of that has changed. Today, we know that there are over 40 billion warm Earth-like worlds in our galaxy alone, and over 40 billion trillion warm Earth-like worlds in the observable universe alone (which is in turn only a speck of the entire universe), moving through stellar systems chock full of water and the building blocks of life (and we now know that life appeared on the Earth pretty much as soon as the Earth cooled down enough to support carbon-based life).
So now the odds are extremely favorable toward a model of the universe that's teeming with life, and we have no reason left to presume that it's at all rare. The only remaining question is the prevalence of intelligent life, and even on that question we have no logical reason to presume that the evolution of intelligent life is extremely rare. Seventy years ago it wasn't totally unreasonable to wonder if there were any other intelligent civilizations out there in the universe. But today, the most reasonable scenario appears to describe our galaxy as a system lushly populated with organic life, and probably thousands or more planets inhabited by technological civilizations, most of which are probably many millions or even billions of years ahead of us, because most of the inhabitable planetary systems in our galaxy are much older than ours:
"We found that most potentially habitable star systems are much older than the Sun and located farther from the galactic centre. By comparing the ages of these systems we estimated that ~77% of potentially habitable star systems are on average ~3.13 billion years older than the Sun. This suggests that any intelligent life in the Galaxy is likely to be incredibly more advanced than we are assuming that they have evolved under similar timescales than we have."
"The Age Distribution of Potential Intelligent Life in the Milky Way," Daniel Legassick, 2015
In light of these newly discovered facts, it would be a far greater mystery if our planet weren't being visited by alien civilizations from time to time. Fermi was perfectly correct to ask the question "Where is everybody?" He should've looked up, because the answer appears to be: "all around us."
Last edited: