To Measure a Black Hole’s Ultimate Spin, We Have to Go to Space

Despite their depiction as massive monsters that simply suck in everything, including light, astronomers know black holes actually spin. And they spin really, really quickly at that. Determining just how quickly is key to understanding how they impact their immediate vicinity, but also the galaxies that surround them. A new paper by Tegan Thomas of the University of Virginia and her colleagues, available in pre-print on arXiv, has some good news and bad news on that front. The bad news is we cur