ALEX CHADWICK, host:
This is DAY TO DAY. I'm Alex Chadwick.
Federal authorities are still looking into exactly what happened Wednesday when a passenger on a plane in Miami was shot and killed by federal air marshals. According to an official account, the man was pretending to carry a bomb off the plane. The marshals ordered him to get on the ground and then opened fire when he reached into his backpack. That got the Explainer team at the online magazine Slate wondering, if the man really had been toting a bomb, could the bullets have set it off. Here's Slate's Andy Bowers.
ANDY BOWERS reporting:
It depends on the explosives. Some bomb materials are highly sensitive to impact. If you shoot a gun at a stick of dynamite, for example, there's a good chance you'll set it off. Others are less susceptible to gunfire. The military tries to make its explosives as durable as it can since you don't want soldiers blowing up from the impact of a single bullet. A block of C4 plastic explosives can withstand a rifle shot without exploding. You can even set one on fire without too much worry.
That doesn't mean a bomb made out of C4 or another less-sensitive explosive, like TNT, is impervious to gunshots. Such a bomb would have a detonator, which is far more vulnerable. The detonator serves as a mini bomb that produces enough energy to blow up the main explosive. If a bullet were to strike the detonator, it could easily set off the more volatile explosives stored inside. You'd have to be an unbelievable shot to pull that off, though. In general, detonators are only about the diameter of a pencil and only a few inches long.
If the man in Miami had been carrying a bomb, the chances of an air marshal accidentally shooting the detonator would be very small. If the bullet had hit TNT, it might have passed right through. It's also possible that a stray bullet could disable the bomb. A bullet that happened to strike a bomb's batteries could jar them loose and cut off power to the detonator.
Although some terrorists use stolen military-grade explosives, many rely on improvised bombs that tend to be far more sensitive. The shoe bomber, Richard Reid, was trying to blow himself up with a very unstable mixture called triacetone triperoxide. He had trouble lighting the fuse. A gunshot might have done the trick.
CHADWICK: Andy Bowers is a Slate senior editor. That Explainer was compiled by Daniel Engber. Transcript provided by NPR, Copyright NPR.
