From LIGO https://twitter.com/LIGO on Twitter: We think the larger of our #GW190521 #BlackHoles, at 85 solar masses, is too large to have formed through collapse of a massive star. So how did this "impossible" #BlackHole form? This video, from @ARC_OzGRav, looks at some of the possibilities https://www.youtube.com/watch?v=hpbmi8oPipY&feature=youtu.be https://twitter.com/LIGO/status/1301146608688656387/photo/1 https://chirp.cooleysekula.net/attachment/67282