OK, so the title is just a tad over-dramatic. However there is an interesting new software tool being developed for tracking the time and date of phone calls or wiretaps, and it requires no special hidden devices or spyware on the targets phone or home. It is simply a matter of listening to the background hum of electrical appliances.

People generally assume that electricity is constant and unchanging. But it isn't. The electrical current that runs all of your household appliances from the range to your computer to your battery charger actually pulses and varies in intensity depending on how many people are using it and on the effective impedance of the wires and the circuitry - both of which can vary based on hundreds of variables.

And when a recording is made of a phone call or of bugged rooms, the background hum of the appliances is not only recorded as well, but so are these fluctuations. Since the fluctuations are similar over large areas, police or other investigators can record the variations in the electrical system and then use newly developed software to match up the recorded hum with their recordings of the electrical variations, and pinpoint the exact time of the conversation.

This may seem relatively trivial, but the technology has already been used to counter the alibi of at least one murder suspect, and is being studied in relation to several other major criminal cases. By simply listening to a refrigerator or an air conditioner, investigators can precisely measure the time of any recordings.

It is a very interesting use of what until now was considered just an imperfection in the electrical system.