Eminent astrophysicist J V Narlikar, when contacted in Pune, said he had seen reports claiming about the mythical bridge, but there was no evidence to suggest that what had been located had links with the bridge mentioned in the Ramayana.
"There is no archaeological or literary evidence to support this claim," eminent historian R S Sharma told The Times of India in Patna.
"The Ramayana itself is not that old. Nor had human habitation occurred 1.75 million years ago," Sharma, an acknowledged authority on ancient Indian history, said.
The oldest evidence of the Ramayana is around 400 BC and running across five strata, its shloka multiplying from 6,000 to 24,000, it comes up to 1200 AD. "Even if you want to rely on literary evidence, the oldest literary evidence available is only from 1500 BC."
Sharma said that even the location of the bridge and of ancient Lanka had yet to be conclusively established.
Indolink.com, Vaishnava News Network and some other US-based news services have claimed that NASA had "discovered" the remains of the mythical bridge, popular in folklore as Hanuman Setu - because of the role of Hanuman and his monkey brigade in laying it - across Palk Strait linking India with Sri Lanka. This bridge was supposed to have been captured by NASA's spaceborne cameras.
However, NASA has officially debunked this claim, saying the agency could not provide specific information about the origin or the age of the chain of islands, "and certainly cannot determine whether humans were involved in producing any of the patterns seen".
The American agency said what had been captured was no more than a 30-km-long naturally-formed chain of sandbanks called Adam's Bridge.
D N Jha, professor of history at Delhi University, said what had been captured by NASA's cameras was a geological formation. The issue had "more to do with geology than history", since the claim was 1.75 million years old. "To link that with Rama or Ramayana is ridiculous."
"Linking just anything found with Ramayana or Mahabharata may be mythology, but it certainly isn't history," said Jha.