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This is another thing that feeds into the Fermi paradox. Previous generations of stars and planets might be too low metallicity to give rise to very complex int
by api 9mo ago
This is another thing that feeds into the Fermi paradox. Previous generations of stars and planets might be too low metallicity to give rise to very complex intelligent life. We might be part of the first crop to evolve as the metallicity of the cosmos reaches a threshold.
Life on Earth is mostly C, H, O, and N, but it makes use of many heavier elements to conduct complex chemical synthesis processes. Some are only used in trace amounts but are still necessary. Then there’s technology which could not have developed to this level without most of the periodic table. Low metallicity is likely to put a ceiling on what can evolve.
You’re not getting spacefaring aliens until you have the building blocks. Then it takes billions of years, and on top of that stable nurseries like Earth are probably rare.
So TL;DR my guess is that we are early and rare.
In a few billion years the galaxy might resemble Star Wars with aliens all over the place, albeit without FTL unless we are very wrong about core physics or there’s some huge aspect of reality we haven’t found yet.
- mr_toad 9mo agoI don’t buy this hypothesis, because we’ve had complex life on land for 250 million years. Evolution is not a steady upwards path (especially when you take into account mass extinctions). There’s no reason an intelligent species couldn’t have evolved on Earth any time in the mesozoic. Just a single million year head start would be huge for a civilization. Seems highly unlikely that the resolution to the Fermi paradox is just that we’re the first intelligent species in the galaxy.
- mcherm 9mo agoI agree. My own suspicion for the resolution of the fermi paradox is that there are 4 steps that we have seen occur only once (or zero times) so it is difficult to measure their probability. If some of those probabilities are significantly lower than we think it could resolve the "paradox". Those 4 steps are: (1) Formation of life (2) Formation of multicellular life (3) Formation of "runaway intelligence", where a species evolves enough intelligence to manipulate their environment in ways that supercede evolution. Parrots and dolphins, for instance, are both quite smart, but don't look close to getting a runaway benefit from that which would allow them to invent technology like agriculture and overpower all other species. (4) Technical civilization manages to manipulate their planet or spread beyond one star system in a way that would be detectable from elsewhere in the galaxy. (Hasn't happened yet.)
- api 9mo agoI don’t think these hypotheses are mutually exclusive. Low metallicity in the past might explain how we could be first even though the galaxy is very old. The conditions did not exist until recently, on cosmic time scales. If the probabilities are also low then you’re not going to get many even when conditions are right.