Experts at the University of Rochester and the University of Washington, have tweaked the infamous Drake Equation, one with Dr. Frank Drake, and the University of Rochester's own new theory of possible extraterrestrial civilisation.
According to a new paper, to be published in Astrobiology, also shows for the first time just what “pessimism” or “optimism” mean when it comes to estimating the likelihood of advanced extraterrestrial life.
The questions posed in the equation are simple “We’ve known for a long time approximately how many stars exist. We didn’t know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilisations might last before becoming extinct. The question of whether advanced civilisations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation,” says Adam Frank, Professor of Physics and Astronomy at the University of Rochester and co-author of the paper.
“The fact that humans have had rudimentary technology for roughly ten thousand years doesn’t really tell us if other societies would last that long or perhaps much longer,” Dr. Frank explained.
But Dr. Woodruff Sullivan of the Astronomy Department and Astrobiology Program at the University of Washington, also co-author of the paper, found they could eliminate that term altogether by simply expanding the question.
“Rather than asking how many civilisations may exist now, we ask ‘Are we the only technological species that has ever arisen?" said Dr. Sullivan. “This shifted focus eliminates the uncertainty of the civilisation lifetime question and allows us to address what we call the ‘cosmic archaeological question’—how often in the history of the universe has life evolved to an advanced state?”
They set out what they call the “Archaeological-form” of the Drake equation, which defines A as the “number of technological species that have ever formed over the history of the observable Universe.”
They then calculate the odds of advanced life developing, then against it occurring in order for humanity to be the only advanced civilisation in the entire history of the observable universe. Then calculated the line between a Universe where humanity has been the sole experiment in civilisation and one where others have come before us.
“Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet,” says Dr. Frank. But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilisation the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilisation has likely happened before.”
Using this approach, the researchers calculate how unlikely advanced life must be if there has never been another example among the universe’s ten billion trillion stars, or even among our own Milky Way galaxy’s hundred billion
But the most astonishing find is that one in 10 billion trillion civilisations may have existed
“To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way. Before our result you’d be considered a pessimist if you imagined the probability of evolving a civilisation on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!” says Dr. Frank.
“The universe is more than 13 billion years old,” replies Dr. Sullivan. “That means that even if there have been a thousand civilisations in our own galaxy, if they live only as long as we have been around roughly ten thousand years—then all of them are likely already extinct. And others won’t evolve until we are long gone. For us to have much chance of success in finding another "contemporary" active technological civilisation, on average they must last much longer than our present lifetime.”
It seems as humanity faces its crisis of sustainability and climate change we can wonder if other civilisation-building species on other planets have gone through a similar bottleneck and made it to the other side?
Source: https://www.rochester.edu/news/are-we-alone-in-the-universe/
According to a new paper, to be published in Astrobiology, also shows for the first time just what “pessimism” or “optimism” mean when it comes to estimating the likelihood of advanced extraterrestrial life.
The questions posed in the equation are simple “We’ve known for a long time approximately how many stars exist. We didn’t know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilisations might last before becoming extinct. The question of whether advanced civilisations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation,” says Adam Frank, Professor of Physics and Astronomy at the University of Rochester and co-author of the paper.
“The fact that humans have had rudimentary technology for roughly ten thousand years doesn’t really tell us if other societies would last that long or perhaps much longer,” Dr. Frank explained.
But Dr. Woodruff Sullivan of the Astronomy Department and Astrobiology Program at the University of Washington, also co-author of the paper, found they could eliminate that term altogether by simply expanding the question.
“Rather than asking how many civilisations may exist now, we ask ‘Are we the only technological species that has ever arisen?" said Dr. Sullivan. “This shifted focus eliminates the uncertainty of the civilisation lifetime question and allows us to address what we call the ‘cosmic archaeological question’—how often in the history of the universe has life evolved to an advanced state?”
They set out what they call the “Archaeological-form” of the Drake equation, which defines A as the “number of technological species that have ever formed over the history of the observable Universe.”
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| The top the original Drake equation the bottom the new "Archaeological-form," Drake equation |
They then calculate the odds of advanced life developing, then against it occurring in order for humanity to be the only advanced civilisation in the entire history of the observable universe. Then calculated the line between a Universe where humanity has been the sole experiment in civilisation and one where others have come before us.
“Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet,” says Dr. Frank. But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilisation the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilisation has likely happened before.”
Using this approach, the researchers calculate how unlikely advanced life must be if there has never been another example among the universe’s ten billion trillion stars, or even among our own Milky Way galaxy’s hundred billion
But the most astonishing find is that one in 10 billion trillion civilisations may have existed
“To me, this implies that other intelligent, technology producing species very likely have evolved before us. Think of it this way. Before our result you’d be considered a pessimist if you imagined the probability of evolving a civilisation on a habitable planet were, say, one in a trillion. But even that guess, one chance in a trillion, implies that what has happened here on Earth with humanity has in fact happened about a 10 billion other times over cosmic history!” says Dr. Frank.
“The universe is more than 13 billion years old,” replies Dr. Sullivan. “That means that even if there have been a thousand civilisations in our own galaxy, if they live only as long as we have been around roughly ten thousand years—then all of them are likely already extinct. And others won’t evolve until we are long gone. For us to have much chance of success in finding another "contemporary" active technological civilisation, on average they must last much longer than our present lifetime.”
It seems as humanity faces its crisis of sustainability and climate change we can wonder if other civilisation-building species on other planets have gone through a similar bottleneck and made it to the other side?
Source: https://www.rochester.edu/news/are-we-alone-in-the-universe/
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