This is what we hear about AUM:
The past, the present and the future are AUM,
And That beyond these three is also AUM
AUM is the most popular and universally recognised Hindu symbol and also the most popular word in Hindu chants and prayers. It is the Divine Word and the originating sound of the universe. It was through meditation that the seers and sages of Vedic times arrived at the idea of a universal sound, eternally resounding in the universe, which they saw as the very origin of the created world.
There is a depth of philosophical meaning in AUM and reciting it correctly has a profound effect on the mind and body.
One of the reasons why we can understand AUM to be the universal sound is because it covers the entire spectrum of sound that human speech is capable of. The first sound of AUM is ‘A’ (as in around), which originates from the lowest point of the throat. The remainder of the word requires the involvement of every region of our speech-apparatus up to the closing of the lips, where the word terminates with ‘M’.
Because AUM starts very low in the diaphragm and travels upward, it has an ascending (uplifting) effect on the one who chants it. Energy is transferred in an upward motion all the way up to the highest centres of consciousness in the head, enhancing the upward movement from our lower centres of consciousness (chakras) to the higher ones, which is an important part of spiritual practice.
The three sounds that make up AUM correspond to the entire cycle of the universe. ‘A’ corresponds to the creation, ‘U’ to the preservation and ‘M’ to the destruction and dissolution of the universe. Therefore the three stages of AUM, ‘A’, ‘U’ and ‘M’ are connected with Brahma, Vishnu and Shiva respectively. The silence that occurs between two repetitions of AUM represents that which is beyond the universe and inexpressible in human speech. This is why the scriptures say: ‘The past, the present and the future are AUM and That beyond these three is also AUM’.
These are just some of the meanings of AUM. There is much more that is simply beyond the scope of this article. Ultimately, it is said that the entire content of the Vedas is enshrined within AUM. AUM symbolises everything – the means and the goal of life, the universe and the Truth behind it, the material and the Sacred, all forms as well as the Formless. Deeper meanings of AUM are sure to reveal themselves to those who chant it and meditate upon its meaning.