One of the areas that I’ve been involved in the last few years is looking at the effects of gravity on the body. Pixar asked me what humans would look like if they had lived in space for 700 years. My opinion was that I did not think 700 years was enough time for significant evolutionary change to occur in humans, but if we look at the data on astronauts and “bed rest” studies, we know that the skeletal muscle gets smaller — about 1% per week — and bone density declines — about
1-2% per month. They’d have tremendous bone density loss and very little muscle mass. If we extend that out to a lifetime of an individual 75 years of age, that person would just turn into a big blob.
At the very end of the film, where the humans are coming out of the space ship back to Earth, they are learning to walk again, stumbling around. When astronauts return from being in space, they often have a hard time walking because of the physiological changes that have occurred. Pixar took what we know and incorporated it into their film.
Prof. James Hicks teaches in the Ecology & Evolutionary Biology Dept. at UC Irvine.