Many of these factors seem, with high probability, like genuine constraints (e.g. a second generation star). But I wonder whether others might be examples of anthropic generalizing from one example (e.g. availability of a specific ratio of elements). Presumably alien life would adapt to whatever conditions actually exist in their world.
Your post got me thinking on a completely different tangent: How much of the filter might be at a high tech level for most species but we managed to escape it based on what resources we actually lacked?
The most obvious example is the amount of U-235. If humans had arose 2 billion years ago there would be about six times as much U-235 on the planet (since U-235 has a half-like of around 700 million years), making it much easier to develop nuclear weapons. That could have a substantial negative impact on a species chance of not wiping themselves out.
I’m not sure how much this would matter in that fission weapons are a lot easier already to produce than fusion weapons. Moreover, this would also make it easier to use nuclear power for productive purposes. Even a Fermi style pile would be much, much easier to construct (Fermi’s original pile did not use enriched uranium). So the ability to use nuclear power in this way would help for simple electricity generation a lot as well as nuclear rockets (which would directly help beating the Great Filter). So overall this seems like a wash without a lot more data.
Is there some other isotope that could have a similar impact? Possibly something that now is very rare so we aren’t paying much attention to it? The other obvious candidates don’t seem to work. For example, tritium has a very short half life but natural processes produce more of it so that shouldn’t matter. Similarly, plutonium 239 has much too short a half-life so that any species that arose even after the first billion years wouldn’t see any substantial amounts of it. Maybe Plutonium-244? It is primordial, has a half-life around 80 million years, so would be around in larger quantities on a young planet. But I don’t know of any obvious fission chain for it, and the quantities produced would be very little, since it is not easily produced in supernovae.
Most accessible nuclear power on our planet isn’t stored as U-235 anyway. We can get a lot more by converting uranium into plutonium, which is heavily restricted because of how much easier it is to make weapons out of, or out of thorium, which is safer and more abundant but requires a different procedure to extract energy which has never been developed for commercial applications.
Many of these factors seem, with high probability, like genuine constraints (e.g. a second generation star). But I wonder whether others might be examples of anthropic generalizing from one example (e.g. availability of a specific ratio of elements). Presumably alien life would adapt to whatever conditions actually exist in their world.
Your post got me thinking on a completely different tangent: How much of the filter might be at a high tech level for most species but we managed to escape it based on what resources we actually lacked?
The most obvious example is the amount of U-235. If humans had arose 2 billion years ago there would be about six times as much U-235 on the planet (since U-235 has a half-like of around 700 million years), making it much easier to develop nuclear weapons. That could have a substantial negative impact on a species chance of not wiping themselves out.
I’m not sure how much this would matter in that fission weapons are a lot easier already to produce than fusion weapons. Moreover, this would also make it easier to use nuclear power for productive purposes. Even a Fermi style pile would be much, much easier to construct (Fermi’s original pile did not use enriched uranium). So the ability to use nuclear power in this way would help for simple electricity generation a lot as well as nuclear rockets (which would directly help beating the Great Filter). So overall this seems like a wash without a lot more data.
Is there some other isotope that could have a similar impact? Possibly something that now is very rare so we aren’t paying much attention to it? The other obvious candidates don’t seem to work. For example, tritium has a very short half life but natural processes produce more of it so that shouldn’t matter. Similarly, plutonium 239 has much too short a half-life so that any species that arose even after the first billion years wouldn’t see any substantial amounts of it. Maybe Plutonium-244? It is primordial, has a half-life around 80 million years, so would be around in larger quantities on a young planet. But I don’t know of any obvious fission chain for it, and the quantities produced would be very little, since it is not easily produced in supernovae.
Most accessible nuclear power on our planet isn’t stored as U-235 anyway. We can get a lot more by converting uranium into plutonium, which is heavily restricted because of how much easier it is to make weapons out of, or out of thorium, which is safer and more abundant but requires a different procedure to extract energy which has never been developed for commercial applications.