The ear in a human body is said to be the most sensitive and powerful radar available in this world. Apart from its unique capacities of sensing, filtering and identifying a large variety of sounds in the spectrum of audible frequencies - in its most general state, a healthy ear in the human body can as well sense smaller (low in pitch and loudness) sounds from long distances if the external disturbances are removed. For instance, we can hear the buzzing sound of a bee from about 6ft in an otherwise silent surrounding. Controlled experiments in advanced telecommunication centers (including AT & T Bell Labs, New Jersey, USA) have recorded several such extraordinary sensing capabilities of human ears. These include the successful 'listening' of the physiological tremors by different groups of human subjects under different soundproof experimental conditions. Modern technology is still far away from developing an electronic analogue of the natural device like the human ear. The fine sensor - the tympanum, inside our ears - is made up of an ultra-thin membrane of thickness of about 4 X10-10 inches only. Even in the average normal conditions, i.e., without any practice of Nada Yoga, the sensing power of this unimaginably thin membrane is about ten thousand times more than that of the most powerful sensor developed by the state of art technology till date. Theoretical analysis of the models of the structure and functioning of the human ear indicates that it can discriminate about four hundred thousand different kinds of sounds. There have been noted musicians who could recognize the individual sound of each of the hundred odd instruments being played jointly in an orchestra. The tympanum of our ears focuses the receiving sound waves at a point and sends them through a connecting tube where these waves are transformed into electrical signals. Three tiny bones, forming a triangle, serve the purpose of a piston at this juncture. As the signals reach the snail- shaped lymphous hole at the deeper end of the ear, the sounds 'contained' in them become clearer and are perceived as 'heard'. The membrane of this third part of our natural hearing device is directly connected with the brain. Each of the sonic vibrations received at the tympanum are propagated deep inside the connecting channel by about 3500 tiny particles working as electrical transmitters. The corresponding signals are received by the brain in less than a thousandth fraction of a second. The brain instantaneously sends the signals to the memory cells (layers in the neuronal network) where the associated sound is recognized. This is how the long multi-phased process of 'hearing' takes place in a negligible amount of time, in our biological 'telephone'. The distance within which the sonic vibrations can enter as valid inputs for processing in the ear depends on some neuro-physiological parameters. Hence the number of muscles at the entrance of the tympanum plays an important role here, too. For example, the number of such muscles in a human ear is nine whereas in a ear of a horse this number is seventeen; a horse can listen from proportionately longer distances than us. Our memory has a direct link with the power of perception and recognition of the sounds received by our ears. Napoleon-I had amazingly sharp audio-memory. He could remember the names of each of the soldiers in his army who had not even come in contact with him and used to correctly recognize their voices. Alexander the Great is also said to have been blessed with such extraordinary memory; he was able to recognize the voices heard after a long span of time. He could even locate the place of the source of a voice even if he had heard it from a very long distance.

- courtesy Akhand Jyoti