Do the stones used in building of Ram Setu really float on water?

There are 3 issues/questions in the Question .

1. Whether theWho built Ram Setu? Do the stones really float on water?re are floating rocks?
2. Was Rama Setu or Adam's bridge built by floating rocks?
3. Another hidden question here - Has the Rama Setu or Adam's bridgeanything to do with Ramayana or the bridge constructed by Sri Rama?

I) Are there floating rocks?

Yes, there are. Pumice.

Pumice (pronunciation: /ˈpʌmᵻs/), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored.Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser.

Pumice - Wikipedia

II) Was Rama Setu or Adam's bridge built by floating rocks?

Scientists have been claiming that the stones ofRama Setu are actually coral formation.

III) hidden question here - Has the Rama Setu or Adam's bridge anything to do with Ramayana or the bridge constructed by Sri Rama?

Many people are thinking and confidently stating that Ravana's Lanka is in fact present day Sri Lanka, situated in the South-eastern region of India.

However, the narration given by Sage Valmiki in Sundara Kanda gives a different picture about the location of Ravana's Lanka.

1) After flying 100 Yojanas over the ocean towards Southern direction, and reaching Lanka, Sri Hanuma observes the scenic beauty of flora of the Lanka. Sage Valmiki describes elaborately in Sundara Kanda.

संततान् विविधैर्वऋकैः सर्वर्तुफलपुष्पितैः |
उद्यानानि च रम्याणि ददर्श कपिकुञ्जरः || (Sundara Kanda 2nd Sarga 13th Sloka)

"Hanuma saw various glorious pleasure-groves filled by various trees that give fruits and flowers in all seasons and beautiful gardens ."

2) After reaching Asoka Garden, Sri Hanuma observes the beautiful flora in that Garden.

 नन्दनम् विविध उद्यानम् चित्रम् चैत्ररथम् यथा || ५-१५-११
अतिवृत्तम् इव अचिन्त्यम् दिव्यम् रम्यम् श्रिया वृतम् |
द्वितीयम् इव च आकाशम् पुष्प ज्योतिर् गण आयुतम् || ५-१५-१२
पुष्प रत्न शतैः चित्रम् पन्चमम् सागरम् यथा |
सर्व ऋतु पुष्पैर् निचितम् पादपैर् मधु गन्धिभिः || ५-१५-१३
नाना निनादैः उद्यानम् रम्यम् मृग गणैर् द्विजैः |
अनेक गन्ध प्रवहम् पुण्य गन्धम् मनो रमम् || (Sundara Kanda 15th Sarga 11 -14th Slokas)

"Like the garden of Nandana, a celestial garden, wonderful like Caitraratham, a garden of Kubera, surpassing all, unfathomable, an excellent one, a beautiful one consisting of glory together with flowers like clusters of stars, like a second sky wonderful with flowers, like hundreds of diamonds, like a second oceanwith flowers of all seasons, spread with trees having the smell of honey, beautiful with groups of animals of various sounds, diffused with many smells with an auspicious soul pleasing smell."


It is necessary to study the following phrase used by Sage Valmiki :

सर्वर्तुफलपुष्पितैः - Trees that give fruits and flowers in all seasons

Modern researches revealed that the equatorial zone on the Earth has the special climatic feature of allowing the trees to bear flowers and fruits in all seasons.
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The various causes now enumerated are sufficient to enable us to understand how thegreat characteristic features of the climate of the equatorial zone are brought about; how it is that so high a temperature is maintained during the absence of the sun at night, and why so little effect is produced by the sun's varying altitude during its passage from the northern to the southern tropic.

As a result of this condition of the earth and atmosphere, there is no check to vegetation, and little if any demarcation of the seasons. Plants are all evergreen; flowers and fruits, although more abundant at certain seasons, are never altogether absent;while many annual food-plants as well as some fruit-trees produce two crops a year. In other cases, more than one complete year is required to mature the large and massive fruits, so that it is not uncommon for fruit to be ripe at the same time that the tree is covered with flowers, in preparation for the succeeding crop.

(Source: The Climate and Physical Aspects of the Equatorial Zone, by Alfred Russel Wallace)

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3) Sri Hanuma flew 100 Yojanas over the ocean.

1 Yojana = 13 Kms (approx.)

Hence, Sri Hanuma flew 1,300 Kms. over the ocean.

We have to calculate the aerial distance from Southern tip of India to Northern tip of Lanka only, as Sri Hanuma flew 100 Yojanas over the ocean to reach Ravana's Lanka.

The Latitude and Longitude of Sri Lanka at Jaffna, the Northern tip of Sri Lanka, is 09°45'N and 80°02'E.

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4) Current day Srilanka was connected to India by land route.

This is backed by the evidences given on the wikipedia site.

"The bridge is 30 miles (48 km) long and separates the Gulf of Mannar(southwest) from the Palk Strait (northeast).

Some of the sandbanks are dry and the sea in the area is very shallow, being only 1 to 10 metres (3 to 30 ft) deep in places, which hinders navigation.

It was reportedly passable on foot up to the 15th century until storms deepened the channel: temple records seem to say that Adam’s Bridge was completely above sea level until it broke in a cyclone in 1480."

Source : Adam's Bridge

wikipedia.org

This confirms that srilanka and india were connected by land route .The current adam's bridge doesn't confirm the dimensions given in Ramayana.

Hence, Sri Lanka cannot be Ravana's Lanka.

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5) Further, according to the Ocean God, who assured Sri Rama, that the bridge being constructed would allow the passage to Him and the vanara-s assisting Him.

विधास्ये येन गन्तासि विषहिष्ये ह्यहम् तथा |
न ग्राहा विधमिष्यन्ति यावत्सेना तरिष्यति || २-२२-२८
हरीणाम् तरणे राम करिष्यामि यथास्थलम् |

"O, Rama! I shall make it possible to see that you are able to cross over. I will arrange a place for the monkeys to cross me and bear with it. As far as the army crosses me, the crocodiles will not be aggressive to them."

अयम् सौम्य नलो नाम तनुजो विश्व कर्मणः |
पित्रा दत्त वरः श्रीमान् प्रतिमो विश्व कर्मणः || २-२२-४४

"O, excellent man! This one, named Nala, a glorious person, is the son of Vishvakarma; who was given a boon by his father and is equal to Visvakarma."

एष सेतुम् महाउत्साहः करोतु मयि वानरः |
तम् अहम् धारयिष्यामि तथा हि एष यथा पिता || २-२२-४५

"Let this greatly energetic monkey build a bridge across me. I can hold that bridge. He is just the same as his father."

So the bridge got constructed by Sri Rama would be in place, as long as He and his army passes over it, ie., it will remain intact for their to and fro journeys. There after it will collapse.

Sri Rama performed the return journey by Pushpaka Vimana and hence the bridge would have been collapsed immediately thereafter.