In most of the world’s religions, three lokas (world) are mentioned viz. Heaven, Hell and Earth. But in Hinduism, there are fourteen lokas. These fourteen lokas together are called as Brahmanda. Seven lokas are above earth and seven lokas below earth. All this together extends over millions of Yojanas (one Yojana equal to 13 Kilometer approx.). The various lokas or regions are situated one over another. Earth is the center of the Brahmanda. The God has created countless Brahmandas (Cosmic shells) floating in His creative will like particles in a beam of light. The fourteen worlds are enumerated in Srimad-Bhagavatam, Second Canto, fifth Chapter. The lokas also find mention in Vishnu Purana, chapters 3 & 6.
Earth is unique as salvation can be attained on it. Salvation is the state free from the cycle of birth and death and a state of absolute and eternal bliss.
Above the earth are seven worlds of increasing spiritual splendor. Covering that is a belt of darkness surrounding the upper part of Anda-lataha. The lokas above earth are as follows:
1. Bhur-loka – It is the earth.
2. Bhuvarloka – It is located between earth and sun and abode of munis and siddhas. It is identified with Earth's atmosphere and the space which is in the immediate neighborhood of Earth.
3. Svar or Swarga loka - It is located between sun and polar star and abode of Indra and other demi-gods. Some Puranic references equate Suvarloka to the Solar System. As per these the Suvar loka is consisted of nine sub divisions or sectors:
a) Druva Mandala (Polar star Region),
b) Sani Mandala (Saturn Planet Region),
c) Brihaspati Mandala (Jupiter Planet Region),
d) Angaraka Mandala (Mars Planet Region),
e) Sukra Mandala (Venus Planet Region),
f) Budha Mandala (Mercury Planet Region),
g) Nakshatra Mandala (star fields visible at night),
h) Chandra Mandala (Moon Region),
i) Surya Mandala (Solar Region).
4. Mahar or Marar loka or Gandharba loka, the region of celestial spirits – The abode of Bhrigus and other enlightened saints. It is deserted at the end of kalpa but not destroyed. It can be equated to the region (Stellar Neighborhood) of stars.
5. Janaloka – The abode of Brahma’s children. These live as long as Brahma whose lifespan is one
kalpa. It can be equated to the Milky Way galaxy.
6. Tapoloka – The abode of vairagis (ascetics) who are un-consumable by fire. It can be equated with the inter-galactic structures like the Local Group of Galaxies.
7. Satyaloka – The abode of Brahma where he resides along with immortals. It can be equated to the Universe itself containing several Worlds of Galaxies.
8. Vishnu loka – The abode of Vishnu (sometimes called Brahma or Rudra loka) and those who are free from re-birth.
There are seven nether (Posterior) lokas below the earth. These can be layers inside the earth. Covering that is pitch darkness surrounded by Anda-kataha (the shell of the egg-like cosmos). These lokas are as follows:
1. Atala - Atala is ruled by Bala – a son of Maya – who possesses mystical powers. It can be equated with upper crust.
2. Vitala - Vitala is ruled by the god Hara-Bhava – a form of Shiva, who dwells with attendants including ghosts and goblins as the master of gold mines. It can be equated with lower crust of earth.
3. Sutala - Sutala is the kingdom of the pious demon king Bali. It can be equated with Asthenosphere of earth
4. Talatala - Talatala is the realm of the demon-architect Maya, who is well-versed in sorcery. Shiva, as Tripurantaka, destroyed the three cities of Maya but was later pleased with Maya and gave him this realm and promised to protect him. It can be equated with upper mantle of the earth.
5. Mahatala - Mahatala is the abode of many-hooded Nagas (serpents) – the sons of Kadru, headed by the Krodhavasha (Irascible) band of Kuhaka, Taksshaka, Kaliya and Sushena. They live here with their families in peace but always fear Garuda, the eagle-man. It can be equated with mantle of the earth.
6. Rasatala - Rasatala is the home of the demons – Danavas and Daityas, who are mighty but cruel. They are the eternal foes of Devas (the gods). They live in holes like serpents. It can be equated with outer core of earth.
7. Patala - The lowest realm is called Patala or Nagaloka, the region of the Nagas, ruled by Vasuki. Here live several Nagas with many hoods. Each of their hoods is decorated by a jewel, whose light illuminates this realm. It can be equated with inner core of earth.
1. These fourteen worlds (lokas) also represented within human body. The seven upper worlds viz. Satya-loka, Tapo-loka, Jana-loka, Mahar-loka, Svar-loka, Bhuvar-loka and Bhu-loka, are represented in human body by energy centers of Sahasrara chakra, Ajna chakra, Vishuddha chakra, Anahata chakra, Manipura chakra, Swadhisthana chakra, Muladhara chakra respectively. The seven lower worlds Atala-loka, Vitala-loka, Sutala-loka, Talatala-loka, Mahatala-loka, Rasatala-loka and Patala-loka are represented in legs from thighs to toes.
2. The seven upper worlds are also invoked by Gyatri mantra. The Gyatri Mantra, found in Rig veda, and authored by the sage Vishwamitra, is as under:
ॐ भूर्भुव स्व: | तत्सवितुर्वरेण्यम् | भर्गो देवस्य धीमहि | धियो यो न: प्रचोदयात्
The mantra makes an appeal to the almighty through various lokas as under:
a) Om represents the whole of reality and beyond.
b) The first line of this verse is about the Bhur, Bhuva and Swar Lokas (the Earth, its atmosphere and the Solar System).
c) The next lines are about the other lokas.
It is an appeal to the almighty – The almighty (ॐ), the spiritual energy (भूः), the destroyer of the sufferings (भुवः), the embodiment of happiness (स्वः), the luminous like sun (तत्), the creator of the world (सवितुः), the most exalted (वरेण्यम्), the destroyer of sins (भर्गोः), the divine (देवस्य); the reciter meditate (धीमहि) him to enlighten the intellect (धियोः यो न:) and inspire for good deeds (प्रचोदयात्).
Note: Please see my article giving complete explanation of Gyatri mantra on 21.07.2018 namely “Gyatri Mantra– the seed of Bliss.