Ya'all, it's the most wonderful time of the year: Fat Bear Week! Brown bears in Katmai National Park and Preserve are putting on the pounds before they hibernate. During this time, their metabolism, heart and breathing rate slow way down and they recycle their waste internally. Today, we look at the cool (and peculiar) biological processes taking place during hibernation. Plus, we talk through some other science headlines we're obsessing over, including the light pollution from satellites and how gravity affects antimatter.Read a science headline you want to know more about? Email us at shortwave@npr.org.