After 30 years of arguing that black holes never release "information," astrophysicist Stephen Hawking now believes the galactic traps eventually do.

A black hole is an object, usually a collapsed star, that is thought to be so massive that even light cannot escape its gravitational pull.

In the 1970s, Hawking, author of A Brief History of Time, said black holes are not totally "black," but actually emit tiny amounts of matter and energy.

He theorized that once a black hole forms, it never releases information about the matter it has gobbled up.

This "Hawking radiation" created a paradox, because the laws of quantum physics say such information can never be completely destroyed.

Hawking now says some of the information can be determined by what a black hole emits.

"A black hole only appears to form but later opens up and releases information about what fell inside," Hawking told the British Broadcasting Corp.'s Newsnight program. "So we can be sure of the past and predict the future."

He will present the mathematics behinds his revised ideas at the 17th International Conference on General Relativity and Gravitation in Dublin on July 21.

If the revision is correct, then Hawking and theoretical physicist Kip Thorne, of the California Institute of Technology, will lose a bet they made with John Preskill, also of Caltech.

The pair bet "information swallowed by a black hole is forever hidden and can never be revealed."

If Preskill correctly bet against their idea, he wins an encyclopedia.