Seeing a bright light, floating above your body, being guided by an angel. All of these are common elements of reported near-death experiences, but what’s really going on? Ian Sample meets Sam Parnia, an intensive care doctor and associate professor at NYU Grossman school of medicine in New York City who has spent his career exploring the boundary between life and death. He tells Ian how he believes these experiences can be explained and what medicine can learn from them. Help support our independent journalism at theguardian.com/sciencepod