Some people just off the top of their dome assume, "There must be other civilizations out there." But these scientists are saying that there's a real possibility the Earth is so unique that we're the only advanced civilization in the whole thing.
gizmodo.com
The researchers argue that the presence of large oceans, plus Earth’s shift from single-lid tectonics (a stable surface layer) to modern plate tectonics about 1 billion years ago, were critical to the rapid development of complex life. This geological activity not only created the initial conditions necessary for life to emerge but also led to diverse environments with varying climates and ecosystems, which promoted the evolution of advanced life forms capable of developing technology and complex societies.
According to the new study, plate tectonics are crucial for developing complex life and advanced civilizations. Earth’s plate movements create diverse habitats, recycle nutrients, and regulate climate—all vital for life. It’s important for plate tectonics to last for 500 million years, Gerya explained, because biological evolution of complex multicellular life is extremely slow. “On Earth, it took more than 500 million years to develop humans from the first animals, which appeared around 800 million years ago,” he said.
Technology develops from everyday needs, such as making tools, farming, creating clothing, and making weapons, the authors argue, adding that fire and electricity are “essential” for the development of intelligent civilizations. Complex civilizations, they write, are unlikely to emerge in strictly ocean-based environments.
According to Stern and Gerya, it’s likely quite rare for planets to have both continents and oceans along with long-term plate tectonics, and this possibility needs to be factored into the Drake Equation.
By including these new factors and estimates, the researchers estimate that the chance of a planet having both continents and oceans and long-term plate tectonics is very small—less than 0.2%. To put that into perspective, it’s like finding just two suitable planets out of every 1,000.
Plugging this value into the Drake Equation produces a rather discouraging result, at least as far as the presence of advanced aliens is concerned. The modified Drake Equation suggests that advanced civilizations are extremely rare, with the chance of planets having the right conditions being between 0.0034% and 0.17%. This means there could be anywhere from as few as 0.006 to as many as 100,000 active, communicative civilizations in our galaxy, with the actual number likely being on the lower end, considering the limited time these civilizations might communicate due to potential societal collapse or extinction.
“On the other hand, the chances of finding planets potentially suitable for civilizations—yet without any civilizations or with already extinct civilizations—are notably higher,” Gerya explained. “This could be done by remote sensing of exoplanets.”
Gerya explained that, while the upper bound value of 100,000 seems large, it’s the low number that’s more important. Because the low estimate is really close to zero, it means there’s a good chance there might not be any other civilizations in our galaxy. This would help explain why we haven’t detected any signals from other civilizations yet.
In the past, the Drake Equation gave a much higher low-end estimate, suggesting that it was almost certain we weren’t alone and that there should be at least 200 civilizations trying to communicate with us. Since we haven’t found any, this old estimate seems wrong, Gerya said. The new, much lower estimate (close to zero) makes it more understandable why we haven’t heard from anyone else: There might simply be no one else out there to hear from—a rather spooky possibility.
The closest galaxy to us is 2,500,000 light years away. So if we really are the only ones in this galaxy, and the nearest advanced life could only come from another galaxy, it would take them AT LEAST 2.5 million years to reach us traveling one-way at the highest possible speed. And that doesn't account for the fact that it's theoretically impossible for anyone to travel that fast, or the fact that in reality they'd spend millions of years exploring and/or settling in every other planet and system along the way and likely would never even come close to reaching us.
We really might be completely alone and never get another visitor for however long our civilization lasts.
Updated Formula on Alien Intelligence Suggests We Really Are Alone in the Galaxy
An adjustment to the famous Drake Equation could radically refine estimates of intelligent civilizations in our galaxy.
gizmodo.com
The researchers argue that the presence of large oceans, plus Earth’s shift from single-lid tectonics (a stable surface layer) to modern plate tectonics about 1 billion years ago, were critical to the rapid development of complex life. This geological activity not only created the initial conditions necessary for life to emerge but also led to diverse environments with varying climates and ecosystems, which promoted the evolution of advanced life forms capable of developing technology and complex societies.
According to the new study, plate tectonics are crucial for developing complex life and advanced civilizations. Earth’s plate movements create diverse habitats, recycle nutrients, and regulate climate—all vital for life. It’s important for plate tectonics to last for 500 million years, Gerya explained, because biological evolution of complex multicellular life is extremely slow. “On Earth, it took more than 500 million years to develop humans from the first animals, which appeared around 800 million years ago,” he said.
Technology develops from everyday needs, such as making tools, farming, creating clothing, and making weapons, the authors argue, adding that fire and electricity are “essential” for the development of intelligent civilizations. Complex civilizations, they write, are unlikely to emerge in strictly ocean-based environments.
According to Stern and Gerya, it’s likely quite rare for planets to have both continents and oceans along with long-term plate tectonics, and this possibility needs to be factored into the Drake Equation.
Plugging in the numbers
To figure out how likely it is for a planet to have both continents and oceans, Stern and Gerya looked at how much water is needed on the planet’s surface. They found that an Earth-size planet needs to have between 0.007% and 0.027% of its mass in water for both continents and oceans to exist. Stern and Gerya then compared this to the overall possible range of water that planets can have, which is between 0% and 3.8% or even between 0% and 55%, depending on how they formed. For plate tectonics, the scientists used data showing that only about 33% of planets have the right chemicals to form sufficiently dense tectonic plates needed for plate tectonics. Of those, only about half are big enough and have enough gravity to support plate tectonics.By including these new factors and estimates, the researchers estimate that the chance of a planet having both continents and oceans and long-term plate tectonics is very small—less than 0.2%. To put that into perspective, it’s like finding just two suitable planets out of every 1,000.
Plugging this value into the Drake Equation produces a rather discouraging result, at least as far as the presence of advanced aliens is concerned. The modified Drake Equation suggests that advanced civilizations are extremely rare, with the chance of planets having the right conditions being between 0.0034% and 0.17%. This means there could be anywhere from as few as 0.006 to as many as 100,000 active, communicative civilizations in our galaxy, with the actual number likely being on the lower end, considering the limited time these civilizations might communicate due to potential societal collapse or extinction.
“On the other hand, the chances of finding planets potentially suitable for civilizations—yet without any civilizations or with already extinct civilizations—are notably higher,” Gerya explained. “This could be done by remote sensing of exoplanets.”
Gerya explained that, while the upper bound value of 100,000 seems large, it’s the low number that’s more important. Because the low estimate is really close to zero, it means there’s a good chance there might not be any other civilizations in our galaxy. This would help explain why we haven’t detected any signals from other civilizations yet.
In the past, the Drake Equation gave a much higher low-end estimate, suggesting that it was almost certain we weren’t alone and that there should be at least 200 civilizations trying to communicate with us. Since we haven’t found any, this old estimate seems wrong, Gerya said. The new, much lower estimate (close to zero) makes it more understandable why we haven’t heard from anyone else: There might simply be no one else out there to hear from—a rather spooky possibility.
The closest galaxy to us is 2,500,000 light years away. So if we really are the only ones in this galaxy, and the nearest advanced life could only come from another galaxy, it would take them AT LEAST 2.5 million years to reach us traveling one-way at the highest possible speed. And that doesn't account for the fact that it's theoretically impossible for anyone to travel that fast, or the fact that in reality they'd spend millions of years exploring and/or settling in every other planet and system along the way and likely would never even come close to reaching us.
We really might be completely alone and never get another visitor for however long our civilization lasts.
and they know it
