An electromagnetic pulse, or EMP, is a blast of electrical energy, typically of very short duration. Those of low relative energy are experienced as “pops” that you might hear in audio equipment. They can be man-made or of natural origin, and can travel over wires or through the air. The most common EMP of any magnitude that we observe on a regular basis would be lightning.
Amateur radio operators, or hams, have contended with that latter form of EMP ever since they first put wire antennas in the sky. Hit by lightning, those antennas transmit that power to radio gear, blowing thousands of dollars of equipment to kingdom-come in a split second. In spite of your surge protector, if lightning hits your power lines, any computers connected to the house current will probably be history. As will all of your audio and video gear, and the microchips in your refrigerator and microwave. Not to mention anything else with delicate electronic components that is unfortunate enough to get between that pulse and the ground.
Hopefully, you didn’t get lost during that short tutorial, but it should help you understand the potentially disastrous risks we face as we look at EMPs and their effects on page two.