Aging is a process that affects not only living beings. Many materials, like plastics and glasses, also age—i.e. they change slowly over time as their particles try to pack better—and there are already computer models to describe this. Biological materials, such as living tissue, can show similar behavior to glasses except that the particles are actual cells or bacteria which have their own propulsion. Researchers at the University of Göttingen have now used computer simulations to explore the aging behavior of these "living" glassy systems. There was a surprise in that the activity of the particles can actually drive aging, which has potential consequences for a number of applications. Their research was published in Physical Review Letters.