A tidally locked planet does not rotate in relation to its sun. One side is always day, one, always night. This is caused by tidal forces pulling all planets towards this same equilibrium, so it’s completely stable once it does occur…a tidally locked planet at an earthlike distance from the sun would be scorching heat on one side, freezing ice on the other.

What about at different distances? Is there a band of orbital distance where the night side of a tidally locked planet is warm enough for liquid water? Or one far away enough that the day side can have oceans?

  • Björn Tantau@swg-empire.de
    16·
    9 months ago

    Who knows, maybe life is possible on the ring of twilight where it’s not too hot and not too cold. The planet where the Twi’leks in Star Wars are from is that way. Always sounded plausible to me.

    • Exocrinous@lemm.eeOPEnglish
      11·
      9 months ago

      Been doing some googling. Most stars are dwarf stars, and the habitable band of a red dwarf is so close the tidal forces are way stronger. It might turn out that most habitable planets are tidally locked.

      There’s a book called The City In The Middle Of The Night that takes place on a tidally locked planet. It has politics, science fiction, and lesbians.

  • montar@lemmy.ml
    6·
    9 months ago

    Temperatures would be okay in the twilight zone, not sure about water, but winds would blow you out of your shoes.

    • Exocrinous@lemm.eeOPEnglish
      2·
      9 months ago

      What about a planet so distant from its star that the day side gets as much light as earth at twilight? 2AU from a sol size star, there should be a quarter as much light during the day. What about there?

      • I Cast Fist@programming.dev
        1·
        9 months ago

        One thing that might also play a huge factor is the planet tilt compared to its host star, like Uranus’ spin. Or would that have a different name? Pole locked?

  • PatMustard@feddit.ukEnglish
    2·
    9 months ago

    Given the crazy temperature differences you get on Mercury I don’t imagine the dark side of a tidally-locked planet would ever be habitable, though maybe a proper atmosphere would change that. There would be a habitable ring around the planet that’s partly-lit; seems like the kind of thing explored in sci-fi a lot (though the only story I can think of is The Last Day by QI/NSTAAF’s Andy Hunter Murray).