4 ms·

It shows no such thing. The Fermi paradox is fun but it explodes into such a massive tree of possibilities that are all untestable that it’s just that… fun. It

by api 3y ago

It shows no such thing. The Fermi paradox is fun but it explodes into such a massive tree of possibilities that are all untestable that it’s just that… fun. It could be that as we explore the universe we find a ton of microbes but few or no other nearby complex lifeforms with any form of intelligence. This would imply that Earth is a special environment for fostering stable complexity, in which case the great filter is still behind us. BTW there are reasons to think Earth might be special: it’s got this nice magnetic field, a huge moon that reduces bombardment, a thick radiation shielding atmosphere, volcanic activity enough to replenish that atmosphere and the landscape, a reasonably stable climate, is not tide locked to its star (as many planets likely are), and orbits a friendly star that doesn’t throw tantrums and blast us with gamma rays. (The sun appears to be a cute fuzzy waggy little puppy as stars go.) We just don’t really know.

DrFalkyn 3y ago
I believe a survey of planetary systems showed that the gas giants were more common closer to the stars (hot Jupiters), and they tended to eject the rocky inner planets. Our solar system might be exceptional because of Saturn preventing Jupiter from migrating inward. Also the collision of Earth with the other body that eventually formed the Moon, as violent and destructive as it was when it happened, may been a big reason why the Earth is tectonically active (which also is the reason for the magnetic field, which helps keep our atmosphere intact) and the presence of the Moon also gives us tidal forces which may have been necessary for abiogenesis, The collision of such a large object at the right time of planetary evolution may have been a low probability event. OTOH, alternatives have bene proposed. The moons of the "hot Jupiters" could get similar benefits as the Moon and the remnants of the collision gives Earth In particular, it is known that the moons of Jupiter experience substantial tidal forces.

by api 3y ago

DrFalkyn 3y ago

I believe a survey of planetary systems showed that the gas giants were more common closer to the stars (hot Jupiters), and they tended to eject the rocky inner planets. Our solar system might be exceptional because of Saturn preventing Jupiter from migrating inward. Also the collision of Earth with the other body that eventually formed the Moon, as violent and destructive as it was when it happened, may been a big reason why the Earth is tectonically active (which also is the reason for the magnetic field, which helps keep our atmosphere intact) and the presence of the Moon also gives us tidal forces which may have been necessary for abiogenesis, The collision of such a large object at the right time of planetary evolution may have been a low probability event. OTOH, alternatives have bene proposed. The moons of the "hot Jupiters" could get similar benefits as the Moon and the remnants of the collision gives Earth In particular, it is known that the moons of Jupiter experience substantial tidal forces.