Want to know what happens after you pass through a black hole? Just look around you. You might land in another universe that is similar to our own, if Stephen Hawking is right. Or in a very different one.
The iconic astrophysicist joked about it this week as he unveiled a proposed solution to a deeply fundamental paradox that has confounded scientists and mathematicians for 40 years.
“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,” he said through his speech synthesizer. “So, although I’m keen on space flight, I’m not going to try that.”
Hawking has Lou Gehrig’s disease, also called ALS, and is confined to a wheelchair, but he has taken a zero-G ride in an airplane and has said he wants to personally travel into space.
Theories collide
“Black holes ain’t as black as they are painted,” Hawking said. They are not the absolute everything-crushers that imprison matter for eternity, as once thought. That’s where his solution comes in.
In our understanding of reality — from infinitesimal subatomic particles to the infinite vastness of space-time — two theories have explained so much, but have also been at odds with each other in key points.
When it comes to black holes, Albert Einstein’s theory of relativity postulates that information about particles passing through them is destroyed. But the equally important quantum theory says that’s impossible — information from the universe can never vanish.
“Since the 1970s, efforts to combine these two theories have led to mathematical nonsense and have become known as the information loss paradox,” said a statement from the conference built around Hawking’s new solution.
Science history
The conference itself was a new page in science history.
Famed cosmologist Laura Mersini-Houghton from the University of North Carolina-Chapel Hill assembled some of the founders of modern physics — many of them Nobel laureates — to hear Hawking and contribute their brain power at KTH Royal Institute of Technology in Stockholm, Sweden.
It was also a gathering of friends. Hawking’s achievements and those of the other scientists have been made possible through the advances of their cumulative work. Hawking presented to an intimate group of about three dozen scientists.
Hologram of matter
In a way, Hawking’s solution to the information loss paradox says that one thing is really happening, but that it gives the appearance that the other thing is happening.
The information is not passing through the black hole, but is being stored on what’s called its “event horizon” in a “super translation.”
Black holes are not objects like balls, but if we picture them that way, we might describe the event horizon as its surface and the super translation a kind of picture painted on the surface by the particles passing through.
“The idea is the super translations are a hologram of the ingoing particles,” Hawking said. “Thus they contain all the information that would otherwise be lost.”
Bottomless pit of gravity
Black holes defy everyday human perception.
When some massive stars die, they collapse in on their own herculean gravity so extremely that they create an area of space-time that is a “bottomless pit that swallows anything approaching too closely,” the organizers say. “Not even light can escape them, since their gravitational pull is so infinitely powerful.”
And the super translation is constant, swift, and forceful as matter pours through the black hole.
As a result, the information ends up “in a chaotic and useless form,” Hawking said. “This resolves the information paradox. For all practical purposes, the information is lost.”
It could appear as if it had been destroyed.
