What would happen to humans if we set foot on Kepler-442b, where the surface gravity is predicted to be about 30% percent stronger than that of earth?

If humans colonized the planet, would it then begin to alter our descendants' bodies significantly over time?

  • $\begingroup$ One non-medical effect would be that it would be much, much harder to leave the planet. $\endgroup$
    – GdD
    Sep 18, 2017 at 10:21
  • $\begingroup$ This would be a good question for worldbuilding.stackexchange.com. There is a lot of sensible educated guesswork that can be done about this question that would be appropriate on that site but not really here. $\endgroup$ Feb 25, 2023 at 19:20

1 Answer 1


We don't have test results for exceeding gravity by little, for exceedingly long periods. Longest tests were of order of a week (see this substantial answer with links and data), at 1.5g acceleration (which, for all practical purposes simulates increased gravity) - that means a typical expedition, like the Lunar expeditions could operate in these conditions just fine, but a colony could encounter unforeseen health problems.

There may be techniques that could mitigate some of the problems of prolonged exposure - e.g. remaining immersed in water causes external pressure to mitigate a large part of the stress on cardiovascular system. Although high-G worlds are definitely low-priority when planning a manned landing; tyranny of the Rocket Equation makes launch/return from these exceptionally expensive.

  • $\begingroup$ As far as I remember, experiments with mice and rats living in artificial gravity for several generations were done about 50 years ago. $\endgroup$
    – Uwe
    Sep 18, 2017 at 11:08
  • 1
    $\begingroup$ @Uwe: Due to the sqare-cube law, experiments on mice scale poorly to human sizes and weights. A mouse can jump up to 45cm up (a good 4-5 times its length), run up a (rough) vertical surface with nearly no slow-down, and fall a couple meters unharmed. The experiments were performed with accelerations around 3g while prolonged human exposure to 1.5g was already causing problems. $\endgroup$
    – SF.
    Sep 18, 2017 at 12:24

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