“A question that various cosmologists have pondered is whether black holes can take on different shapes. The thinking, until recently, has been that they cannot--in four dimensional spacetime other shapes such as black rings collapse into conventional black holes. But the discovery in the last 20 years that the universe is not only expanding but accelerating away from us changes all that. If the rings can be created on the scale of the cosmological constant, which causes this accelerated expansion, then various groups have calculated that perhaps this accelerated expansion can balance the gravitational collapse, making black rings stable.” - Andre