"Even if some future technological breakthrough makes space travel cheaper, the fact that Mars's gravity is only one-third as strong as Earth's is probably fatal to the entire concept of colonizing the planet. All humans, all the apes from which we are descended, all the monkeys from which those apes were descended, and so on back to the first lobefin fish that emerged from the ocean hundreds of millions of years ago -- every one of them lived every moment of its life in Earth's gravitational field. Given what we've seen of the physical damage caused to the human body by a few months at zero gravity on the Space Station, it's hard to imagine that an entire lifetime spent at one-third Earth-normal gravity wouldn't do serious harm. Various schemes have been proposed for modifying Mars's atmosphere and temperature, but we will never be able to change its gravity." -- Infidel 753, from his essay "One Home," on one of several reasons why humans colonizing Mars would be a nonstarter (though using robots like NASA's Perseverance works well). A worthwhile read, bringing some reality into the discussions of colonizing other planets.
(Photo: Mars' Dingo Gap in Gale Crater, taken by Curiosity rover, February 2014; NASA/JPL- Caltech)
