The Hubble Space Telescope, operating above the blurring effects of Earth’s atmosphere, is famous for its razor-sharp views of stars and galaxies, colourful tapestries of nebulas and clouds of debris thrown off in the death throes of countless suns. But it’s ability to resolve stars that swarm in the cores of globular clusters never fails to amaze.
This view of NGC 6139 shows a dense population of ageing stars that formed more than 10 billion years ago during the Milky Way’s infancy. It is visible in amateur telescopes, but an aperture of 12 inches or more is needed to resolve stars toward the core. Globular clusters orbiting the Milky Way all formed at roughly the same time, but what role they might have played in the galaxy’s evolution remains a matter of debate.