About Those Black Holes...

Well, there goes half of the sci-fi genre. Stephen Hawking, the theoretical physicist most famous for his proof that black holes exist, has now announced that black holes do not, in fact, exist. The announcement is not as drastic as it sounds: it's still true that stars can collapse in on themselves, creating a superdense field out of which it's pretty hard to escape. But that last part is important: the very term "black hole" implies that nothing, not even light, can escape from one.

Hawking, who went on to write A Brief History of Time , sparked an ongoing controversy in 1974 when he applied quantum mechanics to the study of black holes and found that the two don't get along. He found that black holes should at least emit some kind of radiation (now called Hawking radiation) but maintained that when one dies it takes everything with it. Other physicists argued that at least something must be able to escape, but Hawking stood his ground. Now, he's finally admitting that his black-hole theory might have been wrong.

Admittedly, it's a pretty technical difference. We have astronomical proof of black holes, and even Hawking admits that most of them probably function as we always thought. The problem lies in the fact that all black holes are different. Geek.com explains:

Specifically, a truly modern understanding of quantum physics seems to mean that light in fact can escape from a black hole. It’s just extremely difficult to do so. In the parlance of astronomers, Hawking is challenging the idea of the event horizon.

The event horizon refers to the edge, or surface, of a sphere of space centered on a black hole within which light has no chance of escaping back into the rest of space. Past the event horizon, no object or signal has the slightest chance of emerging again. Hawking spent the past decade trying to reconcile the latest findings in quantum mechanics with the physical evidence collected through observatories, and that quest has led him to the conclusion that, in fact, even a black hole can’t stop the signal entirely. “The absence of event horizons means that there are no black holes — in the sense of regimes from which light can’t escape to infinity,” Hawking writes.

Because event horizons may have different shapes and characteristics, we can't truly say that light and information can never escape a black hole. Just that it's really, really hard.