This artist’s impression shows the magnetar in the very rich and young star cluster Westerlund 1. European astronomers have for the first time demonstrated that this magnetar — an unusual type of neutron star with an extremely strong magnetic field — probably was formed as part of a binary star system. The discovery of the magnetar’s former companion elsewhere in the cluster helps solve the mystery of how a star that started off so massive could become a magnetar, rather than collapse into a black hole. – ESO/L. Calçada

Related channels: NEUTRON STARS, STARSBLACK HOLES, ASTROPHYSICSCOSMOLOGY, SPACE-TIME, THE UNIVERSE