Four globular clusters in Fornax — annotated

This NASA/ESA Hubble Space Telescope image shows four globular clusters in the dwarf galaxy Fornax.

New observations of the clusters — large balls of stars that orbit the centres of galaxies — show they are very similar to those found in our galaxy, the Milky Way. The finding is at odds with leading theories on how these clusters form — in these theories, globular clusters should be nestled among large quantities of old stars — and so the mystery of how these objects came to exist deepens.

As shown in this annotated image, left to right: Fornax 1, Fornax 2, Fornax 3 and Fornax 5. Their positions within the galaxy are shown in image G.