An article published in the journal “Nature” reports the results of a study on the so-called intracluster light that permeates galaxy clusters. Hyungjin Joo and M. James Jee of Yonsei University in Seoul, South Korea, used the Hubble Space Telescope to examine ten galaxy clusters and the glow within them. The surprising and therefore interesting discovery was that intracluster light is abundant even in the oldest clusters, a sign that the stars that emit it were ejected from their galaxies a long time ago. This suggests that this happened at the same time as the formation and growth of the clusters.