A new study from Hawking also says that black holes may not possess "firewalls," destructive belts of radiation that some researchers have proposed would incinerate anything that passes through them but others scientists deem an impossibility.
(Editor's note: Watch for our feature "The Truth About Black Holes" in the March issue of National Geographic magazine, out February 15.)
The conventional view of black holes posits that their gravitational pull is so powerful that nothing can escape from them—not even light, which is why they're called black holes. The boundary past which there is supposedly no return is known as the event horizon.
In this conception, all information about anything that ventures past a black hole's event horizon is destroyed. On the other hand, quantum physics, the best description so far of how the universe behaves on a subatomic level, suggests that information cannot ever be destroyed, leading to a fundamental conflict in theory.
No Event Horizons
Now Hawking is suggesting a resolution to the paradox: Black holes do not possess event horizons after all, so they do not destroy information.
"The absence of event horizons means that there are no black holes, in the sense of regimes from which light can't escape," Hawking wrote in a paper he posted online on January 22. The paper was based on a talk he gave last August at a workshop at the Kavli Institute for Theoretical Physics in Santa Barbara, California.
Instead, Hawking proposes that black holes possess "apparent horizons" that only temporarily entrap matter and energy that can eventually reemerge as radiation. This outgoing radiation possesses all the original information about what fell into the black hole, although in radically different form. Since the outgoing information is scrambled,