That finding thrust to the fore an alternative theory to explain the character of globular clusters and their spectral emissions: that M15 and other X-ray-emitting clusters contain a large number of neutron stars.
For nearly a decade, researchers studying globular clusters pinned their hopes on this long-awaited orbiting observatory.
In the images Hubble transmitted to Earth, the red giant's blinding light confounded the results, preventing scientists from determining whether an intense spike of light--the hallmark of a hidden black hole -- truly existed in the globular cluster.
While the full interpretation of Hubble's findings remains speculative, Kulkarni and other astronomers note that this new scenario dovetails with recent groundbased observations suggesting M15 and other globular clusters may possess a surprising abundance of single neutron stars and binaries.
Other teams, including scientists at the Parkes (Australia) Radio Observatory, have found radio pulsars in the globular clusters 47 Tucanae, M28 and M4.
These findings strongly indicate that neutron stars -- both alone and as part of a binary star system -- play a key role in the evolution of globular clusters, say Kulkarni and other researchers.
Although large telescopes are really needed to visually saviour the beauty that fully resolved globular
clusters can give, if you are travelling south on holiday this summer even a pair of 10x50 binoculars will allow you to enjoy some of the splendour of Omega Centauri.