"Well, you don’t know that humans can’t survive indefinitely at 1/3 gee. I know that because no one knows that, so let’s not speculate on what the threshold gra

"Well, you don’t know that humans can’t survive indefinitely at 1/3 gee. I know that because no one knows that, so let’s not speculate on what the threshold gravity would be before we need to “become a different species” would be." Yes, you are correct. However, I think you'll agree that all evidence points in the direction that 1/3 earth gravity would be highly detrimental, somewhere along the scale that zero-gee appears to be...