Taking y­our temperature when sick can be tricky business. A standard mercury thermometer can prove difficult to read, and a rectal one is just plain uncomfortable. In 1991, infrared thermometers that you place into your ears took the work out of it, simplifying and speeding up the process.

Diatek, which developed the first of these kinds of thermometers, saw a need to reduce the amount of time nurses spend taking temperatures. With around one billion temperature readings taken in hospitals in the United States each year and a shortage of nurses, the company set out to shave off the precious minutes otherwise required to watch mercury rise [source: NASA Science and Technical Information]. Instead, Diatek took advantage of NASA's previous advancements in measuring the temperature of stars with infrared technology.

Together with NASA's Jet Propulsion Lab, the company invented an infrared sensor that serves as the thermometer. Aural thermometers with these infrared sensors take your temperature by measuring the amount of energy your eardrum gives off into the ear canal [source: NASA Science and Technical Information]. Since the eardrum is inside our bodies, it acts as an accurate sensor for the energy, or heat, inside of our bodies that increases when we get sick. Hospital models can perform a temperature reading in less than two seconds [source: NASA Science and Technical Information].