New research might eventually result in lie detectors that require no physical contact with the subject.
The Human skin contains millions of sweat glands, that are connected to pores at the surface by tiny ducts. These ducts were originally thought of as straight tubes, but detailed images produced in recent years have revealed that they are actually helical.
Our skin may contain millions of tiny "antennas" in the form of microscopic sweat ducts, say researchers in Israel. In experiments, they found evidence that signals produced by bouncing electromagnetic waves off the tiny tubes might reveal a person's physical and emotional state from a distance.
"When you look at this through the eyes of an electrical engineer, it is very familiar," says Aharon Agranat of the Hebrew University of Jerusalem. "It immediately ignited the thinking that perhaps they also behave as helical antenna."
The ducts would need to conduct a current. And since the ducts are filled with sweat, they do indeed conduct when hit with an electromagnetic wave, although not at the very high frequencies needed.
Experiments performed by the Israeli researchers suggest that they do somehow work as antennas.
Yuri Feldman, who initiated the research, says current may be conducted within the ducts at high frequencies through a mechanism known as "proton hopping," with protons jumping rapidly – in the order of hundreds of femtoseconds – through hydrogen bonds near the surface of cells lining each duct.
Treating the skin as an array of helical antennas could open up a new way of measuring physiological changes from a distance, the researchers say.
This is because perspiration should change the conductivity of each sweat duct. And, since perspiration is linked to other physiological parameters, such as blood pressure and pulse rate, measuring this change would reveal a person's health and mental state.