The smashup that rejuvenates

For elderly stars, the fountain of youth may be only a collision away.

Close-up of the core of the Milky Way globular cluster NGC 6397 reveals several blue straggler stars, each labeled with the prefix BSS. Peter Edmonds/NASA

Evidence for the rejuvenating power of collisions comes from studying bright, young-looking stars residing in globular clusters, the oldest stellar groupings in the Milky Way.