No Black Holes? Here’s What Stephen Hawking Actually Said

Laura Dattaro in Popular Mechanics:

Hawking-mdnA four-page scientific paper about a theoretical physics question has been making the media rounds this week. That should be no surprise, though, given the author—Stephen Hawking—and the claim he appears to make: There are no black holes. But that's far from the end of the story.

The study, published on the open-access research site arXiv, does, in fact, include the words “there are no black holes.” But the sentence continues on: “—in the sense of regimes from which light can't escape to infinity. There are, however, apparent horizons which persist for a period of time.”

The problem of the black hole's event horizon, the boundary beyond which nothing can escape, is one Hawking raised in the 1970s. That's when he discovered, contrary to popular belief of the time, that black holes radiate energy. This means there is no such thing as a black hole from which nothing can escape.

So what is actually new about Hawking's latest paper?

“That's a really good question,” says Don Marolf, a theoretical physicist who studies black holes at the University of California, Santa Barbara. “Most people that I know that read the paper see this as an expression of his opinion on a current debate without necessarily adding new scientific ingredients.”

The debate comes down to a deceivingly simple question that has all kinds of implications for understanding the nature of the universe: If you drop information into a black hole, can you ever get it back?

More here.