Online news editor David Grimm shares stories on evidence for the earth being hit by supernovae, record-breaking xenotransplantation, and winning friends and influencing people with human sacrifice.
 
Staff news writer Jocelyn Kaiser joins host Sarah Crespi to discuss how small membrane-bound packets called “exosomes” might pave the way for cancer cells to move into new territory in the body.  
 
[Image: Val Altounian/Science]