Thorne's 1988 Wormholes Revived Time-Travel Theory as Hawking's 1992 Conjecture Rejected It
Updated
Updated · Yahoo! Voices · Aug 4
Thorne's 1988 Wormholes Revived Time-Travel Theory as Hawking's 1992 Conjecture Rejected It
2 articles · Updated · Yahoo! Voices · Aug 4
Summary
Traversable wormholes proposed by Kip Thorne and colleagues in 1988 reopened serious physics debate over travel to the past, moving the idea beyond Kurt Gödel’s highly artificial 1949 rotating-universe solution.
A 1991 model from Thorne’s group tested the grandfather paradox with a ball emerging from a wormhole and colliding with its future self, finding self-consistent outcomes for every setup they examined.
Those calculations suggested a traveler might influence the past without changing it—echoing Igor Novikov’s self-consistency principle—even though some starting conditions produced multiple, even infinitely many, consistent histories.
Stephen Hawking pushed back in 1992 with his chronology protection conjecture, arguing unknown fundamental laws should block macroscopic backward time travel and closed timelike curves.
Hawking later dramatized that view with a 2009 party for time travelers, sending invitations only afterward; no guests arrived, a stunt he treated as evidence against past-directed time travel.