Last night Stephen Hawking dropped a hint that he’ll reveal something big today. He’ll be expanding on his latest ideas concerning black holes — and the possible passage of information into alternative universes — at the Hawking Radiation conference being held at KTH Royal Institute of Technology.

Stephen Hawking announced August 24, 2015, in Stockholm that he has “now discovered a mechanism by which information is returned out of the black hole.” The legendary physicist said he will expand on his latest idea on August 25 at the Hawking Radiation conference being held at KTH Royal Institute of Technology.

Hawking is in town for a weeklong conference on the information loss paradox, joining 32 of the world’s leading physicists on the campus of KTH Royal Institute of Technology. The Hawking Radiation conference is co-sponsored by Nordita, UNC and the Julian Schwinger Foundation. Nordita is co-hosted by KTH and Stockholm University.

• Read more: Hawking Offers New Solution to Black Hole Mystery: Black Holes Store, and Garble, Information

During a sold-out lecture at Stockholm’s Waterfront auditorium, Hawking said he has been working on supertranslations with Malcolm Perry and Andrew Strominger, and that his findings suggest the possibility that missing information could be stored in alternate universes. (The Cambridge professor also referenced the influence of Richard Feynman, whose work helped lay the foundation for M-theory and string theory.)

That is, that some black holes could be passages to these universes. 

“The message of this lecture is that black holes ain’t as black as they are painted,” he said. “They are not the eternal prisons they were once thought. Things can get out of a black hole both on the outside and possibly come out in another universe.”

“The existence of alternative histories with black holes suggests this might be possible,” Hawking said. “The hole would need to be large and, if it was rotating, it might have a passage to another universe. But you couldn’t come back to our universe. So, although I’m keen on space flight, I’m not going to try that.”

The lecture capped off a remarkable day at KTH. Hawking arrived on campus at 11:20 a.m. and was escorted into the conference by KTH President Peter Gudmundson, while Nobel physics laureate Gerard’t Hooft held forth at the podium.

“It is a great honor to have so many outstanding researchers at KTH and especially Professor Hawking,” Gudmundsson said earlier, during his remarks to the conference participants.