Gravitationally lensed galaxy cluster showing distribution of cold hydrogen gas ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO), STScI, K. Whitaker et al. The bright orange/red dot in the magnified section traces cold dust observed at radio wavelengths using ALMA. This cold dust helps scientists to understand, by inference, the amount of cold hydrogen gas—required for the formation of stars—present in the galaxies in the cluster.