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All these planets are necessarily tidally-locked to their star. That represents an extremely poor environment to try to evolve life in. The only temperate plac

All these planets are necessarily tidally-locked to their star. That represents an extremely poor environment to try to evolve life in. The only temperate place would be a ring at the terminator with the sun permanently just above the horizon. With a very massive moon -- or a double planet, like Pluto/Charon, it might be possible to avoid tidal lock.

xwdv 4y ago
Life on such a world wouldn’t be so bad. It’s basically an inverted ring world. Belief systems would arise to discourage inhabitants from going too far off the ring, either into the burning desert eternally punished by the sun or the icy tundra shrouded in eternal darkness.
- jl6 4y ago
  That burning desert could be a nice location to site their solar power plants, and perhaps the icy tundra could cool their data centers.
  - thechao 4y ago
    An advanced version of this civilization might think of the Earth as uninhabitable: how would you power anything without a builtin planet-scale, locally operable gradient?
    - gota 4y ago
      Can you imagine _war_ in this world? At first armies can march in one direction of the ring or the other, with every natural defense point being sort of a Thermopilae situation Then, technology progresses and certain machines may allow smaller groups to traverse outward for limited periods of time. Analogous to our submarines? Would then flight make the world "flat" and globalized? They can't lay cables across the scorching dor icy deserts, so worldwide comm must either follow the ring or be satellite-based
      - m4rtink 4y ago
        Well, we have a real world example here on Earth in Libya/Nort Africa going on since at least the Roman times. Ocean to the north and desert to the south and only a thin strip in between where to live and wage war in.
- kfarr 4y ago
  Then they develop a 5km long linear city in the Goldilocks zone called The Line
- TEP_Kim_Il_Sung 4y ago
  Sounds like a recipe for planet-spanning super storms.
- wruza 4y ago
  Not so bad if you don’t mind the winds, of course, and all the geological implications.
nine_k 4y ago
One of he planets receives 0.67, and the other, 0.257 of the Sun's light flux. The sun-facing surface, with the star directly above, may be the most habitable part, while the other side is likely colder than Antarctica. With an ocean of liquid water evaporating on the sunlit side and condensing away from it, but flowing back through the ocean (and even rivers), the sunlit area may (theoretically) have relatively a temperate climate, as opposed to being a star-scorched dry desert. This system is less than 5 parsecs / 16 LY from Sun, which likely makes it one of the systems more amenable to detailed research, as bigger telescopes become available.
- fnordpiglet 4y ago
  Wouldn’t the cold side accumulate solid water until the sunlit side is totally dry?
  - pmontra 4y ago
    More probably up to an equilibrium. Everything getting to the cold side will freeze and stay there but it must get there first. My naive model: atmosphere on the warm side goes up, moves with hot humid air toward the cold side, goes down and back to the warm one with cold dry air. Less naive model: we have three large convection cells here on Earth between the pole and the equator. Maybe they have several cells there too. That could slow down the transfer. Furthermore dry is never 100% dry and when there is little water left the transfer will slow down. How much water will be left and for how long, I can't say. There could be the equilibrium I'm thinking about or not. Other variables: volcanoes melt stuff locally, glaciers flow to lower ground, continents move. Edit: I found this paper about weather on tidally locked planets https://www.pnas.org/doi/10.1073/pnas.1315215111 https://www.pnas.org/doi/10.1073/pnas.1315215111
    - moloch-hai 4y ago
      They assume oceans. But without a magnetic field, the only hydrogen is what is locked up in ice or other solids.
  - moloch-hai 4y ago
bilsbie 4y ago
With air and water currents moving that heat the habitable zone could extend somewhat farther in both directions.

xwdv 4y ago

Life on such a world wouldn’t be so bad. It’s basically an inverted ring world. Belief systems would arise to discourage inhabitants from going too far off the ring, either into the burning desert eternally punished by the sun or the icy tundra shrouded in eternal darkness.

jl6 4y ago
That burning desert could be a nice location to site their solar power plants, and perhaps the icy tundra could cool their data centers.
- thechao 4y ago
  An advanced version of this civilization might think of the Earth as uninhabitable: how would you power anything without a builtin planet-scale, locally operable gradient?
  - gota 4y ago
    Can you imagine _war_ in this world? At first armies can march in one direction of the ring or the other, with every natural defense point being sort of a Thermopilae situation Then, technology progresses and certain machines may allow smaller groups to traverse outward for limited periods of time. Analogous to our submarines? Would then flight make the world "flat" and globalized? They can't lay cables across the scorching dor icy deserts, so worldwide comm must either follow the ring or be satellite-based
    - m4rtink 4y ago
      Well, we have a real world example here on Earth in Libya/Nort Africa going on since at least the Roman times. Ocean to the north and desert to the south and only a thin strip in between where to live and wage war in.
kfarr 4y ago
Then they develop a 5km long linear city in the Goldilocks zone called The Line
TEP_Kim_Il_Sung 4y ago
Sounds like a recipe for planet-spanning super storms.
wruza 4y ago
Not so bad if you don’t mind the winds, of course, and all the geological implications.

nine_k 4y ago

One of he planets receives 0.67, and the other, 0.257 of the Sun's light flux. The sun-facing surface, with the star directly above, may be the most habitable part, while the other side is likely colder than Antarctica. With an ocean of liquid water evaporating on the sunlit side and condensing away from it, but flowing back through the ocean (and even rivers), the sunlit area may (theoretically) have relatively a temperate climate, as opposed to being a star-scorched dry desert. This system is less than 5 parsecs / 16 LY from Sun, which likely makes it one of the systems more amenable to detailed research, as bigger telescopes become available.

fnordpiglet 4y ago
Wouldn’t the cold side accumulate solid water until the sunlit side is totally dry?
- pmontra 4y ago
  More probably up to an equilibrium. Everything getting to the cold side will freeze and stay there but it must get there first. My naive model: atmosphere on the warm side goes up, moves with hot humid air toward the cold side, goes down and back to the warm one with cold dry air. Less naive model: we have three large convection cells here on Earth between the pole and the equator. Maybe they have several cells there too. That could slow down the transfer. Furthermore dry is never 100% dry and when there is little water left the transfer will slow down. How much water will be left and for how long, I can't say. There could be the equilibrium I'm thinking about or not. Other variables: volcanoes melt stuff locally, glaciers flow to lower ground, continents move. Edit: I found this paper about weather on tidally locked planets https://www.pnas.org/doi/10.1073/pnas.1315215111 https://www.pnas.org/doi/10.1073/pnas.1315215111
  - moloch-hai 4y ago
    They assume oceans. But without a magnetic field, the only hydrogen is what is locked up in ice or other solids.
- moloch-hai 4y ago

bilsbie 4y ago

With air and water currents moving that heat the habitable zone could extend somewhat farther in both directions.