What It's Like to Die in a Black HoleS

In terms of "coolest ways to die," it's hard to beat "sucked into a black hole." The question's just: what would that entail, exactly? No one has first-hand experience. Would you spend weeks floating past its event horizon, before eventually being ripped apart? Or would you—as string theorist Joseph Polchinski recently proposed—soar into a "seething maelstrom of particles... hit a wall of fire and be burned to a crisp in an instant"?

As it turns out, the answer to that question could change the way we understand the physical universe.

In this month's Nature, Zeeya Merali writes about the coolest current debate in physics. Until recently, most physicists agreed that black hole death involved being ripped apart (and then crushed)—a process they called, charmingly, "spaghettification." But calculations by string theorist Joseph Polchinski seem to indicate that you'd actually get burned alive in a wall of fire at the black hole's event horizon.

Here's how Merali describes the two methods on an accompanying podcast:

Spaghettification

"You cross the event horizon[...] the theoretical surface around the black hole around which light can't escape[...] You kind of just drift past. Slowly, you start to get closer and closer to the core of the black hole. The force of gravity by that point is so strong that it starts to pull on your feet much, much more strongly than it does your head. So you get stretched out, and physicist have a word for this, which, you'll probably understand when I say it: it's called 'spaghettification.' You get ripped apart, and the bits of you that remain get crushed into the center of the black hole."

Wall of Fire

"It's just as unpleasant but it is faster. These calculations carried out by this group in California basically said that when you cross the event horizon, you catch fire. It's do with something called Hawking Radiation. [Black holes] don't just sit there doing nothing [...] they also have a temperature and they can give off radiation. This latest analysis has been looking more closely into the process of how that radiation is given off, and through a complicated set of calculations, they found that these particles that are coming off the event horizon can create an enormous amount of energy that would cause you to... well, would set you on fire."

So: obviously this is an important debate for stoned college kids. But why is it important to physicists? As it turns out, the "Wall of Fire" model precludes Einsteinian relativity—but "fixing" it breaks our current understanding of quantum physics. Physicists are still debating the models: "To completely understand the firewall paradox, we may need to flesh out that dictionary," Harvard's Juan Maldacena told Merali, "but we won't need to throw it out." Another way of resolving all of this: toss someone in a black hole and see what happens.

[Nature, NASA illustration via AP]