Final answer:
Ferdinand Magellan's voyage in 1519 disproved the belief in a direct westward trade route to Asia, revealing the immensity of South America and the Pacific Ocean. His fleet became the first to circumnavigate the globe, although Magellan died mid-voyage. The voyage also revealed the earth's diameter and the need for an International Date Line.
Step-by-step explanation:
Ferdinand Magellan, a Portuguese veteran of Albuquerque's attack on Malacca, planned to discover a westward trade route to the Spice Islands. When the Portuguese king declined to fund the voyage, Magellan approached the king of Spain, who provided the necessary funds and ships. In 1519, Magellan set sail from Spain with a fleet of five ships and a crew of two hundred seventy. He crossed the Atlantic, sailed around the southern tip of South America, and then crossed the Pacific Ocean.
Magellan's voyage revealed the immensity of South America and the Pacific Ocean, disproving the belief that there was a direct westward route to Asia. Although Magellan died mid-voyage, his fleet became the first to successfully circumnavigate the globe, returning to Spain in 1525. Only one ship and eighteen men survived out of the original fleet.
Scientifically, Magellan's voyage also revealed the exact size of the earth's diameter and established the need for an International Date Line. The mariners found upon their return to Europe that they were one day behind the calendar, as they had lost a day while traveling westward counter to the earth's rotation.