I'm wondering what adverse effects might be felt by someone from a planet with, say, 80% of Earth's gravity and a denser, but breathable, atmosphere with a higher concentration of oxygen visiting a planet with around 110% of Earth's gravity, and around the same atmospheric conditions as the Earth.

To clarify,

  • What would this person feel? and,
  • How could they counteract those effects?
  • $\begingroup$ He'll feel stomach ache and he overcomes by passing motion. $\endgroup$
    – user6760
    Commented Apr 3, 2015 at 2:35
  • $\begingroup$ Not sure why this planet with less gravity has a denser atmosphere. Normally, the reverse would be true. $\endgroup$
    – Oldcat
    Commented Apr 3, 2015 at 22:28
  • $\begingroup$ @Oldcat I'm not entirely sure myself, but Venus has lower gravity and a much denser atmosphere, so it's possible. $\endgroup$ Commented Apr 3, 2015 at 23:16

2 Answers 2


I live at sea level and whenever I visit a high-altitude location like albuquerque, I spend about a day feeling short of breath and have a mild head-ache. After that, I feel like I've adapted to thinnest of the air, but even the mildest exercise takes my breath away.

I would guess that your thick atmosphere alien would share my dislike of thin air but their situation would be exacerbated by the heavier gravity. Just standing up would be mild exercise, and a slow walk would be a work-out.

A small bottle of oxygen feeding a nazel canula (or the alien equivalent) would go a long way to make the visit more enjoyable.


As the other answer suggests, it would be rather like a person from sea level - San Francisco, let's say - going backpacking above 10,000 ft in the Sierra Nevada. For a person in good physical condition, it's doable, but you might well feel some effects of altitude sickness. You'd probably want to spend at least several days gradually acclimating to the new pressure - which you could easily do by adjusting the pressure and spin rate (= artificial gravity) of your spaceship.


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