ec@o

A warning sign for black holes, event horizons, naked singularities and other spacetime engineering hazards. Of course, purists will point out that orbits around black holes are just as stable as around any other mass – they don’t suck things in without some friction mechanism – and that many other nasty metrics are not even symmetric. But some physical realism ought to be sacrificed for visual saliency. A black spiral signals an obvious, dynamical danger.

WARNING SIGNS