A sceintific explanation was offered by modern experts about the Gayatri Mantra: According to Astro-Physicists and Astronomers, a Sound is produceddue to the fast movement of Earth, Planets, and Galaxy or the Milky Way, called Akshya Ganga, with some 100,000 million Stars. The Galaxy, the Moon and the Earth-all revolving around the Sun-each moving on their own axis at a mind boggling velocity of 20,000 miles per second, produce the Sound and the Sages named the Super Sound  as OM. The Sum of the Gayatri Mantra states: The Earth (*Bhur), the Planets (*Bhuvaha), and the Galaxy (* Swaha) are rotating on their own axis at a great velocity as the Sound OM, which is the Formless Entity. The total Kinetic Energy genrated by these movements balance the over-all energy consumption of Cosmos and this is named the ‘Pranava’ or the Body Energy ie Mass of Galaxies multiplied by two: Mass x Velocity x 2. That Supreme Entity (God) who manifests in the Form of Utmost Radiance (The San or Savitur) is indeed worthy of surrender (Varenyam). One should meditate (Dheemahi) upon the Light (Bhargo) of that Entity (Devasya) and perform the chanting of  OM. May He(Yo) guide in the right Direction (Prachodayat) our (nah) Intellect (dhiyo)!]]

NOTE: The above are the Two  Versions of Sandhya Vandana Vidhi followed by Scientific Expanation of Gayatri Mantra. The  Essence of Dharma Sindu is continued further.

Brahmachari Dharmas: Tatra Sandhyaatrayam agniparicharanam bhaiksham cha nityam, Tatraagni kaaryam praatah Saayamcha/ Tatra palaasha khadiraashwattha shami samidhah shreshthaastadalaabherka vetasaanaam/ Bhavadcchaabda purvikaa bhikhaa Vipraanaam saacha vipra griheshvewa, Aapaadi Shudra griheshu  Aamaannam griheeyaat/ Asya Brahma Yagnopi nithyah, Saa chopaajkaranaat poorvam /(Trikaala Sandhya, Agni Paricharya and Bhiksaatana are regular duties. Agni Karya is required to be done possibly once in the morning and again in the evening or atleast in the evening properly. Samidhas or twigs of the palasha, khad ira, ashwattha, and shami vrikshaas are the best; failing which Arka or Vetasa samidhas are alternatives. Brahmanas should also perform ‘Bhikshaatana’ by clearly uttering the words of ‘Bhavati Bhikshaam dadaatu’ that too among the Brahmana grihas only, although raw rice among other residences too are acceptable. Yagna Karya is a regular duty of a Brahmana after performing Upakarma.) The left-over food of the Guru, or of elder brother or father might be eaten by a Brahmachaari. Day time sleep, application of kaajala on the eyes, paada rakshaas, Chhatra or sleeping on cots are forbidden acts. Taabula Bhakshana, Abhhyanjana snaana or oil baths and eating in glass plates are prohibited to Brahma chaaris, Yatis and widows. Consumption of honey, impure ( Ashoucha) food, Shraadhaanna is also debarred. Mekhala-Danda-Yagnopaveeta- Koupeena-Kati Sutra are to be worn on the body of Brahmachari always and if any of these items are misplaced or torn, they must be replaced forthwith after discarding the earlier ones in running water flows.  Referrring to the aforementioned Yagnopa -veeta Prayaschitthas, the following be also noted: If the Sacred Thread slips down one’s body by mistake, there must be four Ajyaahutis in the Grihaagni or otherwise by reciting the Mantras of Manojjoti and Vraatapatibhischa/  In case the Sandhyaagni Kaaryaas are deficient, then the Japa of Maanastoke Mantra hundred times. If there is a lacking of Bhiksha then the Japa of this Mantra be done eight hundred times twice over  and resort to Punarupanayana. Alternatively, Tam Vodhiya Japenmantram Laksham chaiva Shivaalaye, Brahma chaari Swadharmaeshu nuunamchet purnametitat/ (  The Brahmachaari concerned should perform a lakh Japaas of Tam Vodhiya Mantra in a Shivaalaya) After his Upakarma, he should recite the Mantra, execute Vishnu and other Devas and thentake up Vedaadhyana. This Mantra is also recited at the time of Aksharaarambha and Vidyaarambha also. In fact in the earlier Yugas even Brahmacharinis were required to recite this Mantra after Upakarma and at Vedaarambha : Dwija Streenaam Yugantarey mounji bandho Vdaayhayanmam chaasiit, Kali Yugetu naitadwayam Atah Streenaam Vedoccharaadou Doshah/   (Brahmanis in Kali Yuga are forbidden to have the Samskaraas of Upanayana and Upakarma and as such are barred from Vedoccharana is a sin). Anadhyaaya -Adhyayana Dharmas: In Kali Yuga, the Andhyaaya or those days when Vedaadhyana is forbidden are the  two Pratipaada Tithis of any month, two Ashtamis, two Chaturdashis, Purnima and Darsha Tithis, Uttaraayana and Dkakshinaayana, and all the Sankranti days and the Surya and Chandra Grahanas. Excepting these days, Veda Shastraadikaas are required to be read, recited, analysed and cogitated upon about their meaning and even the  ‘Goodaardha’ or Inner import.The Pradosha time of Chaturthi etc.tithis are supposed to be extremely significant for Anadhyaana. However, Vedanga, Ithihasa, Purana and other Shastras are exempted from the forbidden days of Andhyaya. Also, in the context of observing Nitya Karmas, Japas and Kamya Karmas/ Vratas, Yagna Karyas, Veda Parayanas, and Vedopadeshas, Anadhyaa is not applicable. As regards, Anadhyana Dharmas, it is necessary to touch the feet of Guru at the time of commencing and terminating Veda Pathana. Also before ‘Pranavocchaarana’ and after it, Bhumi sparshana or touching Earth is required to bedone. Vedaadhyayana is permitted in the night’s prathama Yaama as also the last. During the middle Yaamas, one should sleep to attain Brahmatwa. Also, no Brahmana could ever curse or entertain any trace of thought to the parents and Guru at any point of time; this has to be strictly observed by way of ‘ Manasaa-Vaachaa-Karmana’ dictum; indeed the goodness one might reap in the Veda pathana or for that matter any Adhyayana would be negated.’Samaavartana: The word Samavartana basically means taking Snaana after securing the blessing and instruction of Guru; hence the origin of the word Snaataka; this is done after providing compensations to the Guru in the form of Bhumi, Gold, Cow, horse, umbrella, foot wear, minumum three Vastras, foodgrains and vegetables. It is said that each Akshara or Alphabet learnt from Guru needs to be paid for by way of redemption of indebtedness to the Guru. A Snaatak is considered so in three ways: Vidya Snaataka, Vrata Snaataka and Paripurna Snaataka. A  student who learns from his Guru in a Gurukula by twelve years is a Vidya Snataka; he who assumes the Upanayana Diksha, Savitri Vrata Diksha and Vedadhyayana for twelve years is a Vidya-Vrata Dikshobhaya Snaataka; finally a person who not only spends far  more than twelve years with his Guru  for Vedaadhayana, Vratas, Sandyhagni Karayas, Bhikshaatanaadi Brahma charyaacharana, Sarva Srotriyaacharana, and Vivahaadi Grihasta Dharmaanucharana like Ritu kaala Bharyaa gamana, and observance of sarva grihastadharmaas is a Sampurna Snaataka. Samaavartana Kaala Nirnaya: Samvartana  is a post-Upanayana Kaala Karya; this needs to be therefore forbidden on Anadhyaaya-Pradosha Kaala, Mangal Shani Vaaraas, Dakshinaayana- and Pousha-Ashaadhas. Thus apart from  the Riktaatraya, Purnima-Amavasya-Pratipaada Tithis, last three Tithis of Shukla Paksha, the complete KrishnaPaksha, Guru-Shukraastamadaadi kaalaas, Dinaksahya Bhadra Vyatipaata doshas etc, the kaala Nirnaya is to be made on any other Shubha Kaalaas are propitious  for the Samvartana Kaala. To execute the Samaavartanaadhikaara Pradhaana Homa, the Shubha Nakshatras are Pushya, Punarvasu, Mrigaseerha, Revati, Hasta, Anuradha, Uttara, Uttaraashaadha, Uttaraabhadra, Rohini, Shravana, Vishakha, Chitra and Jyeshtha. Then the Sankalpa has to be made by the Brahmachaari as follows: Mama Brahmacharya lopa janita Sambhaavita Sakala Dosha Parihaara dwaaraa Samaavartanaadhikaara praaptyaa Shri Parameshwara preetyartham Aajya homa purvakam Krucchatrayamaacharishye/  After the Sankalpa since Kuucchaatraya Vrata is being initiated, Agni Pratishtha be done and after Chakshusi Aajyena,  Four Ajyaahutis be done mainly to Agni-Vaayu and Surya , besides one Aajya each to Agni-Prithivi and Maha Devata; Vaya-Antarisha and Maha Devata; Aditya-Dyuevata/ Ashwini Kumaras; Chandra-Nakshatra- Dikpalaka and Maha Devata ; and  to the Eight-some of Agnim Dwirvibhaavasum Shata Kratum Vasum Agnim Vaayum Suryam Prajaapatim/  The finale Mantraayukta Ajyaas be executed as per the Procedure and Prayaschitta Prayoga be completed before the Samavartana Sankalpa be made by the Brahmachari Vatu himself addressing the Parents if aliveand perform Naandi Shraadha before the Snataka Vrata. The do’s and don’t’s of the Snataka Vrataas includethe following:  There should be no Snaana without ‘Shastra Vidhi kaarana’; no sleep in nudity excepting Stree sangama kaala; no running and jumping in rains; no mounting of trees; no getting into water wells; no swimming across rivers or water-bodies by hands; no act tending to risk in general and so on. Besides the must-do’s  include Nitya Yagnopaveeta dharana;  Nitya dharana of Jalayuka kamadalu, Chhatra; Shira Vastra; paada  raksha ,  Suvarna Kundala, Dharbha Mushti, Nityaadhyana-parata; Anaacharana of eka bhojana and eka paatra with Bharya; Nitya Bhojana to three or five Vipraas and Atithi Seva overnight.The Brahma chaari would resolve as follows:  Shuklaambara dharassaam Sugandhi Priya darshana –ssyaam, Vibhave sati Jeernavaasaa malavadwaasaascha na shyaam, Raktam Vaasah shareera -peedaavaham vaa vastram  na dharayishye/ (I shall wear clean, white and scented robes with good smell; with the aquisition of some wealth I shal discard uncouth and torn clothes; shall not wear red clothes as they disturb my mental peace); except those of my Guru’s I shall never wear other’s clothes, jevellery and maalas; shall never wear other’s yagnopaveetas and footwear; shall  never see the shadow in water; shall not teach to the unworthy about gyan, dharma, vrata as these indeed are worthy of Upadesha; shall not offer  my Ucchishta Bhojan nor the remainder of homa sesha prasaada  to a low class person even a house maid or male helper; shall never stand in well water and perform ‘Aachamana’ as there might be a blemish while doing so in running water; shall not perform Aachamana by the water brought by another person; shall never try to clean one foot with another foot of my own; shall never move about with a hidden head in the day time; shall never take my food or greet another person with my footwear on; shall never draw or drag a chair or bench with my feet; shall try to perform only that many Vratas which I could perform properly; in case deficiencies are noticed in the conduct of Vratas that I perform, I shall observe Upavasa one day but is the deficiencies occur to my wanton negligence then I shlaa observe Upavasa for three days; and shall provide food for atleast three Brahmanas at each of my own meal).