I'm going to talk about something that I've been thinking about for a while, and have written about in some of my sci-fi stories.
Everybody knows that Mars and Venus both have different surface gravities from Earth, because of their lesser masses. Mars has ca. 37% of Earth's gravity, and Venus has ca. 90%. This means that if you reach your full Earth height, say 6 feet, then you're 37% of your potential height on Mars and 90% of your potential height on Venus.
Because the surface gravity value (sgv) for Venus is so similar to that of Earth, it's possible that people born on Venus will be able to return to Earth to live if they so choose, though life would be more than slightly physically uncomfortable for them.
However, those people who are born on Mars would have to stay there, unless they eventually develop suits that could artificially support their bodies. Obviously, muscles that have developed to cater for the much lighter gravity of Mars will be absolutely hopeless for dealing with the more intense gravity of Earth; a person born on Mars will almost three times what they do at home, and they will know about that in the worst way when they visit Old Earth.
The same problem applies to every other planet in the Galaxy--wherever we spread in space over the coming millennia, we will almost certainly never run into the same sgv as Earth on any other planet. The implication is that the Human race ultimately becomes a vast family of different species--not only because we'll be mixing fairly freely with any other races we find out there among the stars, but also because we'll be changing bodily with each new sgv and phsyical environment we encounter.
Everybody knows that Mars and Venus both have different surface gravities from Earth, because of their lesser masses. Mars has ca. 37% of Earth's gravity, and Venus has ca. 90%. This means that if you reach your full Earth height, say 6 feet, then you're 37% of your potential height on Mars and 90% of your potential height on Venus.
Because the surface gravity value (sgv) for Venus is so similar to that of Earth, it's possible that people born on Venus will be able to return to Earth to live if they so choose, though life would be more than slightly physically uncomfortable for them.
However, those people who are born on Mars would have to stay there, unless they eventually develop suits that could artificially support their bodies. Obviously, muscles that have developed to cater for the much lighter gravity of Mars will be absolutely hopeless for dealing with the more intense gravity of Earth; a person born on Mars will almost three times what they do at home, and they will know about that in the worst way when they visit Old Earth.
The same problem applies to every other planet in the Galaxy--wherever we spread in space over the coming millennia, we will almost certainly never run into the same sgv as Earth on any other planet. The implication is that the Human race ultimately becomes a vast family of different species--not only because we'll be mixing fairly freely with any other races we find out there among the stars, but also because we'll be changing bodily with each new sgv and phsyical environment we encounter.