For almost 50 years, astronomers have puzzled over the youthful appearance of stars known as blue stragglers... They shine brightly, they are older than they appear, and they have, disconcertingly, gained mass at a late stage of life... Now, Mathieu and Wisconsin colleague Aaron Geller, writing Dec. 24 in the journal Nature, show that blue stragglers, in most if not all cases, steal that mass from companion stars and that they sometimes do so by crashing into their neighbors, a scenario once thought far-fetched by astronomers. In the new Nature report, Geller and Mathieu show that the mass-gathering ways of...