Knocking on Heaven's Door - Lisa Randall [90]
Making particle physics predictions is very different from evaluating risk in the world, and we can only skim the surface of the realities pertinent to risk evaluation and mitigation in a single chapter. Furthermore, the black hole example won’t readily generalize since the risk is essentially nonexistent. Nonetheless, it does help guide us in identifying some of the relevant issues when considering how to evaluate and account for risks. We’ll see that although black holes at the LHC were never a menace, misguided applications of forecasting often are.
RISK IN THE WORLD
When physicists considered predictions for black holes at the LHC, we extrapolated existing scientific theories to as yet unexplored energy scales. We had precise theoretical considerations and clear experimental evidence that allowed us to conclude that nothing disastrous could happen, even if we didn’t yet know what would appear. After careful investigations, all scientists agreed that the risk of danger from black holes was negligible—with no chance that they could be a problem, even over the lifetime of the universe.
This is quite different from how other potential risks are addressed. I’m still a bit mystified how economists and financiers a few years back could fail to anticipate the looming financial crisis—or even after the crisis had been averted possibly set the stage for a new one. Economists and financiers did not share a uniform consensus in their prognoses of smooth sailing, yet no one intervened until the economy teetered on collapse.
In the fall of 2008, I participated in a panel at an interdisciplinary conference. Not for the first or last time, I was asked about the danger of black holes. The vice-chairman of Goldman Sachs International, who was seated to my right, joked to me that the real black hole risk everyone was facing was the economy. And the analogy was remarkably apt.
Black holes trap anything nearby and transform it through strong internal forces. Because black holes are characterized entirely by their mass, charge, and a quantity called angular momentum, they don’t keep track of what went in or how it got there—the information that went in appears to be lost. Black holes release that information only slowly, through subtle correlations in the radiation that leaks out. Furthermore, large black holes decay slowly whereas small ones disappear right away. This means that whereas small black holes don’t last very long, large ones are essentially too big to fail. Any of this ring a bell? Information—plus debts and derivatives—that went into banks became trapped and was transformed into indecipherable, complicated assets. And after that, information—and everything else that went in—was only slowly released.
With too many global phenomena today, we really are doing uncontrolled experiments on a grand scale. Once, on the radio show Coast to Coast, I was asked whether I would proceed with an experiment—no matter how potentially interesting—if it had a chance of endangering the entire world. To the chagrin of the mostly conservative radio audience, my response was that we are already doing such an experiment with carbon emissions. Why aren’t more people worried about that?
As with scientific advances, rarely do abrupt changes happen without any advance indicators. We don’t know that climate will change cataclysmically, but we have already seen indications of melting glaciers and changing weather patterns. The economy might have suddenly failed in 2008, but many financiers knew enough to leave the markets in advance of the collapse. New financial