Galaxies live in great clusters, like swarms of bees.
The astronomers have been hunting for stray stars in two clusters, Virgo and Fornax. But although people looked for these 'lost sheep' before, they didn't find them. We and another group have between us found more than 160 of these objects. There may be as many stars living out in the 'wilderness' of intergalactic space as live in the 'cities' - the galaxies. Having all these extra stars is a problem.