• queermunist she/her
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    4511 days ago

    We managed to escape our gravity well with technology from the 20th century.

    K2-18bians could be at our technological level and still not escape their gravity well. I think a planet twice as big as ours would require rockets as heavy as the pyramids of Giza just to reach orbit, never-mind exiting their planet’s orbit into deeper space.

    • Sulv [he/him, undecided]OP
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      10 days ago

      Yeah if Earth’s gravity is 9.8 m/s2, I think that would mean a planet twice the mass would have a gravity of ~96m/s2. Correct me if I’m wrong physicist hexbears.

      Edit: upon cursory reading it seems much more complicated than this. Basically the force needed to leave the gravitational pull doesn’t necessarily directly correlate to the gravity exerted by the object, size and distance are involved too

      • ZWQbpkzl [none/use name]
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        10 days ago

        Twice the mass is twice force twice the acceleration. Gravitational force is linear to the mass of one of the objects. It would be 19.6m/s2 if the radius was the same but the radius is larger and that’s inverse quadratic. Double the radius, quarter the acceleration. Although I really doubt that planet is only double our mass.

        2.6x the radius of earth, 8.63±1.35 the mass of earth.

    • SkingradGuard [he/him, comrade/them]
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      1310 days ago

      I think a planet twice as big as ours would require rockets as heavy as the pyramids of Giza just to reach orbit, never-mind exiting their planet’s orbit into deeper space.

      Aw hell, this is how we get Stargates