This week's top story has little to do with anything on our home planet. Instead, it offers up some cosmic escapism—or, more darkly, a reminder that as grim as things may sometimes seem here on Earth, our situation could be much, much worse.
Black holes are notoriously voracious—so voracious, in fact, that some of them have even been observed tearing apart and devouring entire stars (and, presumably, any accompanying planets—see what I mean about how things could be worse?). The supermassive black hole at the center of the Milky Way, for instance, is thought to gobble up a star every million years or so, whenever one happens to unfortunately wander too close for comfort to the insatiable 4-million-solar-mass monster.
But recently astronomers have spied something extraordinary and entirely unexpected from such grisly feasts. Sometimes, it seems, star-devouring black holes can suffer indigestion, burping out scraps years after their stellar meals were thought to have ended. This material can't be coming from beyond a black hole's event horizon—a point of no return past which even light itself cannot escape. Instead, it must somehow be sourced from a poorly understood reservoir somewhere outside that boundary, like a whirling accretion disk. Such disks are formed when matter falling into a black hole is inevitably shredded by the black hole's gravitational grip, but no one really understands how exactly the ripped-up remnants of a whole star can linger so long in a disk.
Our expert-authored top story from astronomer Yvette Cendes offers some speculative-but-plausible answers, and explains how solving this messy mystery could help unlock new frontiers in our understanding of the most extreme environments in the universe.
Thoughts? Questions? Let me know via e-mail (lbillings@sciam.com), Twitter or Bluesky.
Thanks for reading, and I'll see you next time.
—Lee Billings
