CAMBRIDGE, Mass. — “A black hole has no hair.”

That mysterious, koan-like statement by the theorist and legendary phrasemaker John Archibald Wheeler of Princeton has stood for half a century as one of the brute pillars of modern physics.

It describes the ability of nature, according to classical gravitational equations, to obliterate most of the attributes and properties of anything that falls into a black hole, playing havoc with science’s ability to predict the future and tearing at our understanding of how the universe works.

Now it seems that statement might be wrong.

Recently Stephen Hawking, who has spent his entire career battling a form of Lou Gehrig’s disease, wheeled across the stage in Harvard’s hoary, wood-paneled Sanders Theater to do battle with the black hole. It is one of the most fearsome demons ever conjured by science, and one partly of his own making: a cosmic pit so deep and dense and endless that it was long thought that nothing — not even light, not even a thought — could ever escape.

But Dr. Hawking was there to tell us not to be so afraid.

In a paper to be published this week in Physical Review Letters, Dr. Hawking and his colleagues Andrew Strominger of Harvard and Malcolm Perry of Cambridge University in England say they have found a clue pointing the way out of black holes.