RAM SETHU

Adam's BridgeCoordinates: 9.1210° N 79.5217° E Ramasethu Bridge (Adam's Bridge) (Tamil: atam palam) ( Sanskrit: rama setu, Tamil:iramar palam) meaning "Rama's Bridge", is a chain of limestone shoals, between the islands of Mannar, near northwestern Sri Lanka, and Rameswaram, off the southeastern coast of India. Geological evidence indicates that this bridge acted as former land connection between India and Srilanka.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 3 ft to 30 ft (1 m to 10 m) deep in places, which hinders navigation.
Name Marco Polo travel map shows that he has travelled around Adam's bridge area. His travel book calls this area as SETABUND-RAMESWARA.
The name Rama's Bridge or Rama Setu (Sanskrit; setu: bridge) for the shoal of islands derives from the Sanskrit epic Ramayana (dated from 500 BCE to 100 BCE), in which a bridge from Rameswaram was built by allies of Rama that he used to reach Lanka and rescue his abducted wife Sita from the Asura king, Ravana.The sea separating India and Sri Lanka is called Sethusamudram "Sea of the Bridge". Maps prepared by Netherland cartographer during 1747 which is available in Tanjore Saraswathi mahal library shows this area as RAMANCOIL(can be translated as Ramar Temple). Another map of Mogul India prepared by J.Rennel in 1788 retrieved from same library gives indications that this area would have been called as Rama Temple or Ramar Bridge. Many other maps which is available in University of Chicago websites and other sources call this area with various names like Koti, Sethubandha, Sethubandha Rameswaram etc.Earliest map which calls this area as Adam's bridge is prepared by British cartographer in 1804. Valmiki Ramayan calls mythological built by Lord Rama as setu bandhanam in verse 2-22-76.
Various travel guides,books, dictionary prepared during 18th and 19th century including travel guide written by Marco Polo calls this area as Setabund Rameswara or Ramar Bridge.
The name Adam's Bridge is due to an Islamic legend, according to which Adam used the bridge to reach Adam's Peak in Sri Lanka, where he stood repentant on one foot for 1,000 years, leaving a large hollow mark resembling a foot print. Both the peak and the bridge are named after this legend. The name first appears in the 11th century, mentioned by Alberuni; Ibn Khordadbeh in his Book of Roads and Kingdoms (ca. 850 AD) calls it Set Bandhai or "Bridge of the Sea".
Geology and ecology
Adam's Bridge consists of a series of parallel ledges of sandstone and conglomeration, that is hard at the surface and grows coarse and soft as it descends to sandy banks. In the 19th century, there were two prevalent theories explaining the structure. One considered it to be formed by a process of accretion and rising of the land, while the other surmised that it was formed by the breaking away of Sri Lanka from the Indian subcontinent friable calcerous ridges are broken into large rectangular blocks, which perhaps gave rise to the belief that the causeway is an artificial construction.During periods of lowered sea level over the last 100,000 years, Adam's bridge has provided an intermittent land connection between India and Sri Lanka, which according to famous ornithologists Sidney Dillon Ripley and Bruce Beehler supports the vicariance model for speciation in some birds of the Indian sub-continent.
Early surveys and dredging efforts
Adam's Bridge seen from above the Mannar island, Sri Lanka.Due to shallow waters, Adam's Bridge presents a formidable hindrance to navigation through the Palk strait. Though trade across the India-Sri Lanka divide has been active since at least the first millennium BCE, it has been limited to small boats and dinghies. Larger ocean going vessels from the West have had to navigate around Sri Lanka to reach India' eastern coast.Eminent British geographer Major James Rennell, who surveyed the region as a young officer in the late eighteenth century, suggested that a "navigable passage could be maintained by dredging the strait of Ramisseram [sic]". However little notice was given to his proposal, perhaps because it came from "so young and unknown an officer", and the idea was only revived 60 years later.In 1822, Sir Arthur Cotton (then an Ensign), was entrusted the responsibility to survey the Pamban channel, which separates the Indian mainland from the island of Rameswaram and forms the first link of Adam's Bridge. Geological evidence indicates that this was at one point bridged by a land connection, and some temple records suggest that the connection was broken by violent storms in 1480. Cotton suggested that the channel be dredged to enable passage of ships, but nothing was done till 1828, when some rocks were blasted and removed under the direction of Major Sim.A more detailed marine survey of Adam's Bridge was undertaken in 1837 by Lieutenants F. T. Powell, Ethersey, Grieve and Christopher along with draughtsman Felix Jones, and operations to dredge the channel were recommenced the next year.However these, and subsequent efforts in the 19th century, did not succeed in keeping the passage navigable for any vessels except those with a light draft.
Latest Dating NASA satellite photo of Adam's Bridge—oblique, Sri Lanka to the left It has been suggested that this section be split into a new article entitled Sethusamudram Shipping Canal Project.
Vaishnava News Network and some other U.S.-based news services suggested that it had discovered the remains of the bridge built by Rama and his Vanara army, that is referred to in the Ramayana, and that it was not a natural formation, basing their claim on 2002 NASA satellite footage.Some archaeologists and geologists have presented differing estimates. Thus, a team from Centre for Remote Sensing (CRS) of Bharathidasan University, Tiruchi led by Professor S.M. Ramasamy in 2003 claimed that the, "Rama's bridge could only be 3,500 years old" and, "as the carbon dating of the beaches roughly matches the dates of Ramayana, its link to the epic needs to be explored”.Such claims were rejected as untenable by experts. NASA distanced itself from the claims saying that what had been captured was nothing more than a 30 km long, naturally-occurring chain of sandbanks called Adam's bridge. It also clarified that, "The images reproduced on the websites may well be ours, but their interpretation is certainly not ours. Remote sensing images or photographs from orbit cannot provide direct information about the origin or age of a chain of islands, and certainly cannot determine whether humans were involved in producing any of the patterns seen”Prof. N. Ramanujam, Head, Post Graduate Department of Geology and Research Centre, V.O. Chidambaram College, astrophysicist Jayant Narlikar and a group of professors of Madurai Kamaraj University stated that Adam's bridge is a natural geographical feature which formed some 17 million years ago.