Note the last sentence, which mentions that 40 joules per square centimeter was required. That’s a lot of energy. To put it into context, let’s consider sunlight, which is roughly 1,000 watts per square meter. Doing the math, that translates to 0.1 watt/cm2, which means that in one second, a square centimeter on the earth’s surface gets about 0.1 Joule of energy from sunlight (1 watt = 1 Joule/second). The microwave weapon described above is providing 400 times more energy.

Put in more familiar terms, astrophysicist Dr. Ethan Siegel explained to me in an email, “If you are talking about 40 J/cm2 over the entire human body, that’s about as much energy as a fully loaded Harley Davidson going 100 mph.” Yikes.

Okay, this is all interesting in theory, but do microwave weapons actually exist? Yes. The U.S. military uses a weapon called an active denial system that employs millimeter waves (which are a type of microwave, contrary to what the military website says) to heat up the surface of a person’s skin. It’s unpleasant, which makes the target leave. The military also developed a weapon that can do precisely what the American diplomats experienced in Cuba and elsewhere: It can cause brain damage and can cause people to “hear” sounds that aren’t really there.