Discover – September 2019

(Greg DeLong) #1

70
DISCOVERMAGAZINE.COM


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rotating maelstroms, they discovered some curious


features.


These included, according to Curiel, wormholes


that could lead you out of the black hole and into


another universe, as well as “closed timelike curves”


— looping paths in space-time that would eventu-


ally take a traveler back to the time and place she


began. It sounded like science fantasy, but Einstein’s


and Kerr’s equations suggested that these were real


possibilities.


Not everyone was on board with such fanciful


features lurking within black holes. In fact, most


physicists regarded them as “pathologies of the Kerr


solution,” Chesler says, so unstable as to be effectively


meaningless. “Like a pencil standing on its tip, if


you disturb a black hole in the slightest way, those


features will disappear.”


That, at least, was the presumption when he and


his colleagues decided to carry out the first detailed


numerical simulations of Kerr black hole interiors,


building on the work of others in the field. With any


luck, they’d figure out exactly what goes on inside.


GETTING TO WORK


They had their work cut out for them. “Although


Einstein’s equations have been around for more than


100 years, they are horrendously difficult to solve,”


Chesler says. Curiel calls them “probably the most


mathematically complex equations in physics.”


OUT THERE


Wormhole


Future


Present


Curved


space-time


CLOSED TIMELIKE CURVE


As the rules of


physics break down


within black holes,


unusual conditions


could result in


time travel.

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