LHS 1140 b could be an example of this.
It might have a deep ocean that doesn’t allow for hydrothermal vents to cause abiogenesis (that we know of).
Meaning that it could sustain life but not necessarily create it, meaning anything that lives there would have to be a product of Panspermia.
Also, Dark Oxygen created from magnetic ocean nodes is something we don’t understand enough to properly look for yet, so there could be oxygen on planets without plants.
And thus far panspermia is still far from agreed upon so we could assume if that world has/had got indeed no places with heightened abiogenesis rates it would be sterile
If LHS 1140 b were to somehow have life then it would confirm some type of Panspermia
Well unless we were wrong on it having vents of course.
Also, tidally locked planets likely don’t have a very extreme temperature variation if they have an atmosphere. The heat from the bright side would move down to the dark side, so you could have a planet where the sunny side is hot and tropical and a night side that’s barren and warm.
Would this locking impact plate tectonics if they did occur?
It does, but it wouldn’t automatically shut them down.
An inhabited tidally locked planet would be interesting as the majority of life would probably live on the light side, and overtime slowly colonize the night side.
Well that is as long as the light side isn’t mostly just scorched deserts
Even if they stay relatively near the edge, there probably would be more life on the light side than the dark side. At least for a while.
iirc the twilight region of eyeball planets is known as “the terminator”
I could imagine the terminator being where the biospheres of the night side and the day side interact.
I wonder how deep would creatures venture into the dark…
Depending on where complex life begins on the planet, if it’s on the day side (which is probably the case) then they’d slowly be migrating down until the terminator zone.
The main issue would be the eternal-daylight animals having enough food in the dark side, as photosynthesis is impossible.
That would probably depend on whether or not Chemosynthetic Macroscopic life formed in the darkness.
Couldn’t it gradually adapt still if it evolved in the depths of the light side first?
Adapting isn’t the main issue, its what the producers of the night side would be.
Well as poodelicus said they could be chemoautotrophs. Or perhaps radiotrophs but those are too scarce to fund a proper continental-scale biosphere probably
It has also been suggested that some algae can photosynthesize by moonlight, though this is still being studied.
So like if they have chlorosomes (or whatever thing green sulphur bacteria have) and not chloroplasts?