WORMHOLES – tunnels through space-time that connect black holes – may be a consequence of the bizarre quantum property called entanglement. The redefinition would resolve a pressing paradox that you might be burned instead of crushed, should you fall into a black hole.
Knowing which hazard sign to erect outside a black hole isn't exactly an everyday problem. For theoretical physicists, though, it reveals an inconsistency between quantum mechanics and general relativity. Solving this conundrum might lead to the sought-after quantum theory of gravity.
Relativity says if you fall into a black hole, you would die via "spaghettification" – a gradual stretching by ever-more intense gravitational forces. But last year, when Joseph Polchinski at the University of California in Santa Barbara and colleagues explored the quantum implications of black holes, they hit a problem. Black holes emit photons via something called Hawking radiation, and these are "entangled" with the interior of the black hole and also with each other. This breaks a quantum rule that particles can't be entangled with two things at once.
To preserve quantum monogamy, Polchinski suggested last year that the black hole-photon entanglement breaks down. That causes a wall of energy at the black hole's event horizon that wrecks relativity because anyone falling in would burn up rather turn to spaghetti. Welcome to the black hole firewall paradox.
Possible solutions abound but now two physics heavyweights, Juan Maldacena of the Institute for Advance Study in Princeton, and Leonard Susskind of Stanford University, California, have come up with the most audacious one yet: a new kind of wormhole
that means the entanglement needn't be broken in the first place.