Let's use a Mars-like as an example of a planet that interstellar travelers may settle on. Assume that the spacecraft will provide Earth gravity and atmosphere.
Comparing this new planet to Earth, it has .5g (1/2 the gravity) and has .5bars of atmosphere, or 1/2 the pressure of Earth. Everything else is the same. Water, light, heat, techtonics, length of day and gases in the atmosphere.
In building this world, my travelers build a settlement, and begin having children.
My questions may be basic, but in this first generation that is born on this planet:
1) Will they grow taller? And by how much? 2) Will their lungs develop the capacity to breath unaided? 3) Will their muscles and bones develop naturally for the new world conditions, or will genetics get in the way? If so, how and what?
My last question is we know humans in zero gravity or even on Mars will lose bone and muscle, heart weakens. We suspect if humans born on Earth were to find such a planet, they will need to be aided in breathing like mountain climbers.
Is it realistic to believe that human muscle/bone loss will stop when it reaches what it needs to function at .5g and .5bars of atmosphere, or will our genetic code continue the signal of bone/muscle loss?
It may be a lot to think about, but the scenario I am looking at is what life will be like for the first generation born on a new world that is different from Earth.
And if anyone has ideas on whether the second generation will have it easier, I'd like to hear about that too.