Earth could also be an early Oth-like planet, the first to contain the unique combination of features that we would immediately recognize in retrospect.
Do you have any candidates for these features? Because there are two ways of seeing your argument: a) There are some very rare features (like the moon) that are necessary for life. This makes intelligent life very rare. b) There are some features that Earth has that are necessary for life, and Earth is one of the earliest planets with these features.
a) explains the Fermi paradox by rarity of intelligence, while b) explains it by saying the first intelligence will expand and prevent other from developing independently. But b) requires that we guess what these features could be.
Large moons are rare, but very rare? The Pluto/Charon system is even more extreme than the Earth/Moon in that respect, although obviously it formed under different conditions.
Well, one unusual feature of Earth are the hybrid solar eclipses, caused by the sun and moon having the same apparent diameter. Seems like an extraordinary coincidence that Earth should have this feature in the exact epoch when intelligent life evolved.
Suppose I had a hypothesis about something that was present in many Earth-era planets but not astronomically younger planets. How would I falsify such a hypothesis?
I don’t think something with lottery-low odds like the moon would adequately explain the paradox.
I also recognize the possibility that Earth might not ever become a Tegmark I civilization, much less a III.
Suppose I had a hypothesis about something that was present in many Earth-era planets but not astronomically younger planets. How would I falsify such a hypothesis?
Depends on the hypothesis. We have some pretty good picture about the development of the Milky Way. If your theory was about rates of supernovas or a certain proportion of heavy metals, then we could check whether those happened recently. If it was more specifically about Earth-like planets, we could record the hypothesis, and check it in a few years or decades as our picture of Earth-like planets around other stars gets clearer.
“Suppose I had a hypothesis that all Earth-era and earlier planets shared some feature that some later planets don’t.”
Then we can do the reverse approach—crush all the data we do know, and see what changed about the time our Earth came around. We can then take all these candidates, and check whether any seem plausible, then do some further investigation.
While not logically impossible, a test that requires an astronomical amount of time to attempt is not something I can update on.
That said, there is a fairly low prior that the conditions for a galactic civilization to develop in the current era are better than they were last era. There is, however, quite a bit of evidence that there is not currently a galactic civilization.
Yes, that’s one explanation. Though that doesn’t explain why the Earth is a late Earthlike planet, rather than an early one.
Earth could also be an early Oth-like planet, the first to contain the unique combination of features that we would immediately recognize in retrospect.
Do you have any candidates for these features? Because there are two ways of seeing your argument: a) There are some very rare features (like the moon) that are necessary for life. This makes intelligent life very rare. b) There are some features that Earth has that are necessary for life, and Earth is one of the earliest planets with these features.
a) explains the Fermi paradox by rarity of intelligence, while b) explains it by saying the first intelligence will expand and prevent other from developing independently. But b) requires that we guess what these features could be.
Large moons are rare, but very rare? The Pluto/Charon system is even more extreme than the Earth/Moon in that respect, although obviously it formed under different conditions.
Well, one unusual feature of Earth are the hybrid solar eclipses, caused by the sun and moon having the same apparent diameter. Seems like an extraordinary coincidence that Earth should have this feature in the exact epoch when intelligent life evolved.
Good point; lottery-low odds are inadequate to explain the paradox. Literally astronomical odds against a feature of Earth would be required.
“Has been observed to not have a large moon” is not something that we can say about 99% of observed planets.
Suppose I had a hypothesis about something that was present in many Earth-era planets but not astronomically younger planets. How would I falsify such a hypothesis?
I don’t think something with lottery-low odds like the moon would adequately explain the paradox.
I also recognize the possibility that Earth might not ever become a Tegmark I civilization, much less a III.
Depends on the hypothesis. We have some pretty good picture about the development of the Milky Way. If your theory was about rates of supernovas or a certain proportion of heavy metals, then we could check whether those happened recently. If it was more specifically about Earth-like planets, we could record the hypothesis, and check it in a few years or decades as our picture of Earth-like planets around other stars gets clearer.
Silly me.
“Suppose I had a hypothesis that all Earth-era and earlier planets shared some feature that some later planets don’t.”
Given that we don’t know what the requirements are to be a galactic phenomenon, figuring out which one we don’t have is impossible.
Then we can do the reverse approach—crush all the data we do know, and see what changed about the time our Earth came around. We can then take all these candidates, and check whether any seem plausible, then do some further investigation.
While not logically impossible, a test that requires an astronomical amount of time to attempt is not something I can update on.
That said, there is a fairly low prior that the conditions for a galactic civilization to develop in the current era are better than they were last era. There is, however, quite a bit of evidence that there is not currently a galactic civilization.