Why Gayatri Mantra is a Mahaa Mantra-1

Why Gayatri Mantra is a Mahaa Mantra-1
By Sushma Gupta              see also   Gayatri Mantra-2     Why Gayatri Mantra is a Mahaa Mantra-2
Gayatri Mantra is said to be the Mahaa Mantra. Has anybody thought about it that why is it so? Let us see --  At first sight it seems a prayer for knowledge, but let us analyze it -
It has five parts--
(1) Aum - It starts with Aum - the primordial sound of the Universe. There ls a declaration, that the Tri-Moorti (Brahmaa, Vishnu, and Mahesh) are in Gayatri, and Gayatri is within this primordial sound Aum. How? Its answer is in the Praanaayaam Mantra of Sandhyaa Vandan, which is called the "Extended Gayatri".
Aum Bhoor Aum Buvah Aum Swah Aum Mahah Aum Janah Aum Tapah Aum Satyam
Aum Tat Savitar Varenyam Bhargo Devasya Dheemahi Dhiyo Yonah Prachodayaat
Aum Aapo Jyoti Rasomritam Brahm Bhoor Bhuvas Swar Aum
Aum is the whole containing seven Vyaahriti
Aum is the essence of the Mantra "Tat Savitar Varenyam Bhargo Devasya Dheemahi Dhiyo Yonah Prachodayaat"
Aum is water, the Divine Ras, the nectar, the Brahm Himself
Aum is Bhoor Bhuvah Swah
In short Aum contains everything, Aum is the seed of Creation.
(2) Bhoor Bhvah Swah - These three words are also called Vyaahriti. Bhoor Lok is gross Earth; Swah Lok is the very Heaven; and Bhuvah Lok is the space between them, also called Antariksh. Our Upanishad say that these worlds are in fact the gross, subtle and causal worlds - or Sthool, Sookshm and Kaaran Sansaar. The Taitteerya Upanishad gives a very detailed explanation of the Vyaahriti. Another discovery is this that these represent the very gross, subtle and causal bodies that a person has.
(3) Tat Savitar Varenyam - The adorable Lord Sun, this is in the praise of the Sun God - praise is the essence of Rig Ved.
(4) Bhargo Devasya Dheemahi - We meditate on the Lord's effulgence - meditate is the essence of the Yajur Ved.
(5) Dhiyo Yonah Prachodayaat - Who enlightens our intellects - this is the prayer part and this part is the essence of Saam Ved.
That is why Gayatri Mantra is a Mahaa Mant