Two decades of healthy growth, followed by four to eight decades of slow-motion physical and mental collapse—that’s life, for most of us, despite the efforts of various deluded cranks and tech billionaires. Time spares nothing, and seems particularly to have it out for our faces, paying just as much attention to skin-level deformations (worry-lines, wrinkles, tumorous outgrowths) as it does to the large-scale hollowings and saggings which, over time, change the actual shape of our faces.

To varying degrees we’re all marked by time, or will be soon. We can’t reverse this process, but we can try to understand it. To that end, for this week’s Giz Asks we reached out to a number of aging experts and plastic surgeons to figure out why our faces change shape as we age.