Data from the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array, or ALMA, are combined in this stunning look at a cluster of giant young stars known as Westerlund 1. Some of the most massive suns feature comet-like tails that stretch away from the center of the cluster much like a comet’s tail is blown outward by particles in the solar wind. In the case of Westerlund 1, the tails are caused by thick winds blowing away from hundreds of hot, massive stars near the centre of the cluster. The tails cover enormous distances and indicate the dynamic nature of the cluster environment. Astronomers are studying Westerlund 1, home of a large number of massive stars of various types, to learn more about how such suns lose mass, and at what rate.