New Delhi, Oct. 1 -- During a recent visit to the Maritime Museum in Lisbon, Portugal, I stood before a life-size sculpture of Vasco da Gama. With limited navigation tools, incomplete maps, and only an obscure sense of the uncharted world ahead, I wondered how he might have prepared for his voyages.

More than five centuries ago, when da Gama set sail for India, his ability to foresee danger was limited. Drawing on past explorations, he would have prepared for the risks he could imagine: treacherous storms, giant waves, jagged coastlines, pirates, or dwindling supplies of food and water. These risks were visible and clearly frightening.

Yet one of the greatest dangers of da Gama's first voyage to India was one he did not anticipate. Midw...